57 research outputs found

    Propuestas de trabajo innovadoras y colaborativas e-learning 2.0 como demanda de la sociedad del conocimiento

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    La evolución del tradicional concepto de e-learning está presente, en gran medida, gracias a la introducción de herramientas web 2.0 en los procesos de enseñanza-aprendizaje en la Universidad. Una evolución (e-learning 2.0) que advierte de la promoción de un alumno o alumna comprometido con su aprendizaje, que construye significativamente, que potencia el trabajo en red y que subraya capacidad ante los procesos innovadores mediante el cambio de actitud necesario. El proyecto Redes Interuniversitarias no es más que la verificación y proyección de dichos principios en el intento de la mejora de la calidad

    The climactic conditions limit fruit production and quality in gulupa (Passiflora edulis Sims f. edulis) under integrated fertilization

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    The gulupa (Passiflora edulis Sims f. edulis) is one of the main fruit trees that are part of Colombia's export supply. The objective of this research was to determine the effect of chemical fertilizers alone (control) or together with integrated fertilization (humic acids or vermicompost; two separate treatments), on the yield and quality of gulupa fruit during two consecutive production cycles in the Colombian Amazon foothills. The climatic conditions were monitored and the phenological state of the plant was related to the average temperature, relative humidity, precipitation, solar radiation, and vapor pressure deficit. The integrated fertilization with vermicompost offered better values in productive parameters (fresh weight, number of fruits and equatorial diameter) irrespective of the cycle considered, but the fruit quality attributes were similar irrespective of the fertilization treatment tested. The fluctuations of the climatic variables of precipitation, relative humidity and solar radiation in both cycles (the second rainiest and affected by the ENSO phenomenon) reduced the quality of the fruit (whole fruit firmness by 19%, dry matter and pulp total titratable acidity by 24%, total soluble solids by 8%, individual sugars by 49%, organic acids by 63% and antioxidant capacity by 67%) as well as the productive parameters during the second cycle. These results demonstrate the high degree of influence exerted by the climate on productive and fruit quality attributes that are decisive in the production and marketing of the fruit.This research was supported by the Colombian Ministry of Science through the Bicentennial Doctoral Excellence Scholarship Program to F.M. Authors thank the technical staff of the Universidad Surcolombiana and the Universidad Nacional de Colombia who contributed to the development of this research. This work belongs to the doctoral thesis of F.M. supervised by Dr. M.S.H.G. and Dr. N.G.G. and is part of the collaboration agreement between the Sinchi Institute and the UPCT

    Predictive models based on RSM and ANN for roughness and wettability achieved by laser texturing of S275 carbon steel alloy

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    Laser texturing is increasingly gaining attention in the field of metal alloys due to its ability to improve surface properties, particularly in steel alloys. However, the input parameters of the technology must be carefully controlled to achieve the desired surface roughness. Roughness is critical to the activation of the surface before further bonding operations, and it is often assessed using several parameters such as Ra, Rt, Rz, and Rv. This surface activation affects the properties of the metal alloy in terms of wettability, which has been evaluated by the deposition of ethylene glycol droplets through a contact angle. This allowed a direct relationship to be established between the final roughness, the wettability of the surface and the texturing parameters of the alloy. This raises the interest of being able to predict the behaviour in terms of roughness and wettability for future applications in improving the behaviour of metallic alloys. In this research, a comparative analysis between Response Surface Models (RSM) and predictive models based on Artificial Neural Networks (ANN) has been conducted. The model based on neural networks was able to predict all the output variables with a fit greater than 90%., improving that obtained by RSM. The model obtained by ANN allows a greater adaptability to the variation of results obtained, reaching deviations close to 0.2 µm. The influence of input parameters, in particular power and scanning speed, on the achieved roughness and surface wettability has been figured out by contact angle measurements. This increases its surface activation in terms of wettability. Superhydrophilic surfaces were achieved by setting the power to 20 W and scanning speed to ten mm/s. In contrast, a power of 5 W and a scanning speed of 100 mm/s reduced the roughness values

    On the Laplacian spectra of token graphs

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    We study the Laplacian spectrum of token graphs, also called symmetric powers of graphs. The k-token graph Fk(G) of a graph G is the graph whose vertices are the k-subsets of vertices from G, two of which being adjacent whenever their symmetric difference is a pair of adjacent vertices in G. In this paper, we give a relationship between the Laplacian spectra of any two token graphs of a given graph. In particular, we show that, for any integers h and k such that 1 ≤ h ≤ k ≤ n 2 , the Laplacian spectrum of Fh(G) is contained in the Laplacian spectrum of Fk(G). We also show that the doubled odd graphs and doubled Johnson graphs can be obtained as token graphs of the complete graph Kn and the star Sn = K1,n−1, respectively. Besides, we obtain a relationship between the spectra of the k-token graph of G and the k-token graph of its complement G. This generalizes to tokens graphs a wellknown property stating that the Laplacian eigenvalues of G are closely related to the Laplacian eigenvalues of G. Finally, the doubled odd graphs and doubled Johnson graphs provide two infinite families, together with some others, in which the algebraic connectivities of the original graph and its token graph coincide. Moreover, we conjecture that this is the case for any graph G and its token graph.This research of C. Dalfó and M.A. Fiol has been partially supported by AGAUR from the Catalan Government under project 017SGR1087 and by MICINN from the Spanish Government under project PGC2018-095471-B-I00. The research of C. Dalfó has also been supported by MICINN from the Spanish Government under project MTM2017-83271-R. The research of C. Huemer was supported by MICINN from the Spanish Government under project PID2019-104129GB-I00/AEI/10.13039/501100011033 and AGAUR from the Catalan Government under project 017SGR1336. F.J. Zaragoza Martínez acknowledges the support of the National Council of Science and Technology (Conacyt) and its National System of Researchers (SNI). This research has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 73492

    Mesh size and effort changes in multispecies fisheries in ICES Divisions Vlllc and IXa.

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    Different simulations varying trawl mesh size and effort changes for several fishing units in ICES Divisions VIllc and IXa were carried out. Landings included in the analysis represent most of the catches in the southern area defined as the management unit for hake, megrim; monkfish, horse mackerel, blue whiting and mackerel. Three Nephrops stock s in Divisions Vlllc and IXa are also included. These species are mainly exploited by Spanish and Portuguese fleets, using various fishing gears to exploit different fractions of the populations, and for this reason nine fishing units were used in the analysis

    Cambios de malla y esfuerzo en las pesquerías multiespecíficas en aguas atlánticas de la península Ibérica

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    Se han realizado diferentes ensayos de cambios de malla y esfuerzo para varias unidades pesqueras de las divisiones VIIIc y IXa del CIEM (Consejo Internacional pqra la Exploración del Mar). Los desembarcos incluidos en este análisis representan la mayoría de las capturas de las especies de merluza, gallos, rapes, jurel, lirio y caballa en la zona sur, definida como unidad de gestión. Están también incluidos tres stocks de cigala de estas divisiones. Dichas especies son las principales especies explotadas por las flotas española y portuguesa, que usan diferentes tipos de artes para explotar diferentes fracciones de las poblaciones. Por esta razón en el presente análisis se utilizaron nueve unidades pesqueras.Different simulations varying trawl mesh size and effort changes for several fishing units in ICES Divisions VIIIc and IXa were carried out. Landings included in the analysis represent most of the catches in the southern area defined as the management unit for hake, megrim, monkfish, horse mackerel, blue whiting and mackerel. Three Nephrops stocks in Divisions VIIIc and IXa are also included. These species are mainly exploited by Spanish and Portuguese fleets, using various fishing gears to exploit different fractions of the populations; for this reason, nine fishing units were used in the analysis.Versión del editor0,000

    Revista de Vertebrados de la Estación Biológica de Doñana

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    Contribución al estudio de la bermejuela Rutilus arcasi, Steindachner, 1866 de la cuenca del Júcar (Osteichthyes: Cyprinidae)II. Edad y crecimientoSobre la taxonomía de Barbus comiza Steindachner, 1865 (Ostariophysi: Cyprinidae)Fenología de una comunidad de anfibios asociada a cursos fluviales temporales.Nueva especie para la ciencia de Anolis (Lacertilia: Iguanidae) de Cuba pertenecient eal complejo argillaceusSegregación ecológica en una comunidad de ofidios.El Aguila Imperial (Aquila adalberti): dispersión de los jóvenes, estructura de edades y mortalidaSobre diferencias individuales en la alimentación de Tyto albaInfluencia de las condiciones ambientales sobre la organización de la comunidad de aves invernantes en un bosque subalpino mediterráneoVariaciones en la agregación y distribución de la cabra montés (Capra pyrenaica Schinz,1838) detectadas con un muestreo de excrementosAlimentación del conejo (Oryctolagus cuniculus L. 1758) en Doñana. SO, EspañaSobre la distribución de Barbus meridionales Risso, 1826 (Ostariophysi: Cyprinidae) en la Península IbéricaSobre la distribución de Barbus meridionales Risso, 1826 (Ostariophysi: Cyprinidae) en la Península IbéricaNueva cita de Barbus microcephalus Almaça (Pisces, Cyprinidae) en España.Revisión taxonómica y distribución de Cobitis maroccana Pellegrin, 1929 (Osteichthyes, Cobitidae)Datos sobre una población de Lacerta viviparaSobre la presencia de Emys orbicularis en la provincia de León.Algunas observaciones sobre la captura de quirópteros por Falco subbuteo y Falco tinunculusNyctalus leisleri (Kuhk, 1818) (Mammalia: Chiroptera). Una nueva especie para las islas CanariaNuevos datos acerca de la distribución del topillo campesino Microtus arvalis, PALLAS 1778, en la Península IbéricaPeer reviewe

    CMAG: a mission to study and monitor the inner corona magnetic field

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    Measuring magnetic fields in the inner corona, the interface between the solar chromosphere and outer corona, is of paramount importance if we aim to understand the energetic transformations taking place there, and because it is at the origin of processes that lead to coronal heating, solar wind acceleration, and of most of the phenomena relevant to space weather. However, these measurements are more difficult than mere imaging because polarimetry requires differential photometry. The coronal magnetograph mission (CMAG) has been designed to map the vector magnetic field, line-of-sight velocities, and plane-of-the-sky velocities of the inner corona with unprecedented spatial and temporal resolutions from space. This will be achieved through full vector spectropolarimetric observations using a coronal magnetograph as the sole instrument on board a spacecraft, combined with an external occulter installed on another spacecraft. The two spacecraft will maintain a formation flight distance of 430 m for coronagraphic observations, which requires a 2.5 m occulter disk radius. The mission will be preferentially located at the Lagrangian L5 point, offering a significant advantage for solar physics and space weather research. Existing ground-based instruments face limitations such as atmospheric turbulence, solar scattered light, and long integration times when performing coronal magnetic field measurements. CMAG overcomes these limitations by performing spectropolarimetric measurements from space with an external occulter and high-image stability maintained over time. It achieves the necessary sensitivity and offers a spatial resolution of 2.5″ and a temporal resolution of approximately one minute, in its nominal mode, covering the range from 1.02 solar radii to 2.5 radii. CMAG relies on proven European technologies and can be adapted to enhance any other solar mission, offering potential significant advancements in coronal physics and space weather modeling and monitoring
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