377 research outputs found

    Emigrating from the state school to a public one. A case study on an inclusive school.

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    Con el presente Trabajo de Fin de Grado pretendemos iniciarnos en la investigación educativa. Después de observar que muchas de las familias del centro en el qu e nos encontrábamos de prácticas se desplazaban desde muy lejos, incluso desde otras provincias, nos interesamos por conocer, comprender y analiz ar qué motivaba esta decisión. Elegimos l a investigación etnográfica con estudio de caso, pues consideramos que era la más coherente con nuestro propósito al permiti rnos adentrarnos en lo particular y único de una realidad concreta. Nuestra condición de alumnos que repetían periodo de prácticas por segundo año consecutivo nos colocaba en una posición inmejorable pa ra realizar este tipo de investigación. El estudio se ha realiza do en torno a un pequeño Colegio Público de Educación Infantil y Primaria, para el cual utilizamos una serie de instrumentos y técnicas tales como: entrevistas, cuestionarios, análisis de docu mento y observación participante. De los datos recogidos se deduce que las familias vienen al centro buscando un modelo de escuela alternativo, algunas de ellas en respuesta a la violencia ejercida hacia sus hijos y sus hijas en la escuela de origen. En la elección se valora especialmente elementos cognitivos como qué y cómo se enseña; así como otros de del ámbito de lo afectivo como puedan ser las relaciones que se generan y los valores que se viven, especialmente la participación, la cooperación y el resp eto al medio ambiente

    Comparación de los hábitos de consumo de carne de conejo entre consumidores jóvenes y compradores tradicionales de Sevilla

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    Se estudiaron los hábitos de consumo de carne de conejo de 499 estudiantes universitarios y de 399 compradores en mercados tradicionales de Sevilla (España). Los estudiantes universitarios afirmaron haber probado (67,9%) y consumir actualmente (38,6%) la carne de conejo en menor proporción que los compradores tradicionales (prueban: 84,5%; consumen: 46,6%). Ambos grupos afirman que les gusta esta carne en la misma proporción (78%).Las mujeres, sobre todo jóvenes, afirmaron haber probado y que les gusta en menor proporción esta carne que en el caso de los hombres. Se reveló además un mayor hábito de consumo y preferencia por la carne de conejo de monte en comparación con la del de granja, siendo la carne de conejo de monte preferida a la del de granja por un 88,2% de los consumidores sin distinción de grupo. Se dedujo una disminución del consumo de la carne de conejo entre los jóvenes en comparación con los compradores en mercados tradicionales

    MinkUNeXt: Point Cloud-based Large-scale Place Recognition using 3D Sparse Convolutions

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    This paper presents MinkUNeXt, an effective and efficient architecture for place-recognition from point clouds entirely based on the new 3D MinkNeXt Block, a residual block composed of 3D sparse convolutions that follows the philosophy established by recent Transformers but purely using simple 3D convolutions. Feature extraction is performed at different scales by a U-Net encoder-decoder network and the feature aggregation of those features into a single descriptor is carried out by a Generalized Mean Pooling (GeM). The proposed architecture demonstrates that it is possible to surpass the current state-of-the-art by only relying on conventional 3D sparse convolutions without making use of more complex and sophisticated proposals such as Transformers, Attention-Layers or Deformable Convolutions. A thorough assessment of the proposal has been carried out using the Oxford RobotCar and the In-house datasets. As a result, MinkUNeXt proves to outperform other methods in the state-of-the-art.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

    Permeabilidad de membranas

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    Fil: Payá, Miguel A.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

    Solving NP-Hard Challenges in Logistics and Transportation under General Uncertainty Scenarios Using Fuzzy Simheuristics

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    [EN] n the field of logistics and transportation (L&T), this paper reviews the utilization of simheuristic algorithms to address NP-hard optimization problems under stochastic uncertainty. Then, the paper explores an extension of the simheuristics concept by introducing a fuzzy layer to tackle complex optimization problems involving both stochastic and fuzzy uncertainties. The hybrid approach combines simulation, metaheuristics, and fuzzy logic, offering a feasible methodology to solve large-scale NP-hard problems under general uncertainty scenarios. These scenarios are commonly encountered in L&T optimization challenges, such as the vehicle routing problem or the team orienteering problem, among many others. The proposed methodology allows for modeling various problem components¿including travel times, service times, customers¿ demands, or the duration of electric batteries¿as deterministic, stochastic, or fuzzy items. A cross-problem analysis of several computational experiments is conducted to validate the effectiveness of the fuzzy simheuristic methodology. Being a flexible methodology that allows us to tackle NP-hard challenges under general uncertainty scenarios, fuzzy simheuristics can also be applied in fields other than L&T.This work has been partially funded by the Spanish Ministry of Science and Innovation (PID2022-138860NB-I00, RED2022-134703-T, PDC2022-133957-I00) and by the Generalitat Valenciana (PROMETEO/2021/065).Juan, AA.; Rabe, M.; Ammouriova, M.; Panadero, J.; Peidro Payá, D.; Riera, D. (2023). Solving NP-Hard Challenges in Logistics and Transportation under General Uncertainty Scenarios Using Fuzzy Simheuristics. Algorithms. 16(12). https://doi.org/10.3390/a16120570161

    UNA NUEVA SUBESPECIE EN EL GÉNERO THYMUS L.

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    A new subspecie Thymus hyemalis Lange subsp. saxicola De la Torre et Payá nova is described from subrupicolous meridional-murcian thyme-brushwoods.Se describe una nueva subespecie de Thymus hyemalis Lange (Thymus hyemalis Lange subsp. saxicola De la Torre et Payá nova) con características ecológicas subrupícolas, que aparece en los afloramientos de calizas del subsector Murciano-Meridional

    Solving the time capacitated arc routing problem under fuzzy and stochastic travel and service times

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    [EN] Stochastic, as well as fuzzy uncertainty, can be found in most real-world systems. Considering both types of uncertainties simultaneously makes optimization problems incredibly challenging. In this paper we propose a fuzzy simheuristic to solve the Time Capacitated Arc Routing Problem (TCARP) when the nature of the travel time can either be deterministic, stochastic or fuzzy. The main goal is to find a solution (vehicle routes) that minimizes the total time spent in servicing the required arcs. However, due to uncertainty, other characteristics of the solution are also considered. In particular, we illustrate how reliability concepts can enrich the probabilistic information given to decision-makers. In order to solve the aforementioned optimization problem, we extend the concept of simheuristic framework so it can also include fuzzy elements. Hence, both stochastic and fuzzy uncertainty are simultaneously incorporated into the CARP. In order to test our approach, classical CARP instances have been adapted and extended so that customers' demands become either stochastic or fuzzy. The experimental results show the effectiveness of the proposed approach when compared with more traditional ones. In particular, our fuzzy simheuristic is capable of generating new best-known solutions for the stochastic versions of some instances belonging to the tegl, tcarp, val, and rural benchmarks.Spanish Ministry of Science, Grant/Award Number: PID2019-111100RB-C21/AEI/10.13039/501100011033; Barcelona Council and the "la Caixa" Foundation under the framework of the Barcelona Science Plan 2020-2023, Grant/Award Number: 21S09355-001; Generalitat Valenciana,Grant/Award Number: PROMETEO/2021/065Martín, XA.; Panadero, J.; Peidro Payá, D.; Pérez Bernabeu, E.; Juan-Pérez, ÁA. (2023). Solving the time capacitated arc routing problem under fuzzy and stochastic travel and service times. Networks. 82(4):318-335. https://doi.org/10.1002/net.2215931833582

    Outstanding aspects on the use of spent FCC catalyst in binders

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    4 pages, 3 fiures, 7 tables.-- En: 1st Spanish National Conference on Advances in Materials Recycling and Eco – Energy Madrid, 12-13 November 2009.-- Editors: F. A. López, F. Puertas, F. J. Alguacil and A. Guerrero.FCC is a waste material from petrochemical plants which has interesting properties for preparing binders. FCC is lightly grey in color, and white FCC-portland cements with L*≥85 can be prepared. FCC reactivity is enhanced by grinding and it is attributed to pozzolanic reaction towards lime. Stratlingite is the main hydrated product from pozzolanic reaction, and CSH and CAH are also formed. Reactivity of FCC is high, and low curing temperature does not affect this contribution to strength in hardened mixtures. Additionally, high strength concrete can be easily prepared, and compressive strength greater 100MPa can be reached. Mixtures with low w/b ratio showed good behaviour in carbonation tests.Authors thank to Ministerio de Ciencia y Tecnología of Spain and FEDER the financial support of MAT 2001-2694 and BIA 2004-0052 projects.Peer reviewe

    Use of residual diatomaceous earth as a silica source in geopolymer production

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    The use of binders as an alternative to Portland cement has gained importance in recent years. Among them, geopolymeric binders, developed by the reaction between an aluminosilicate precursor and a high alkalinity solution, have become one of the most promising alternatives. The activating solution generally comprises waterglass and sodium hydroxide. Since waterglass is the most expensive material and has a high environmental impact, using alternative silica sources will lead to more sustainable binders. Previous studies have successfully used rice husk ash (RHA) as a silica source. This research aims to assess the possibility of using diatomaceous earth (or diatomite) as an alternative silica source, like the previous studies with RHA. Diatomite is a sedimentary rock with a high amorphous silica content formed by fossilized diatom remains. In this work, the geopolymer was obtained using a fluid cracking catalyst residue as the precursor and six different activating solution types prepared with commercial products, residual diatomite (from beer and wine industries) and RHA. The results open a new possible route for the reuse and recovery of diatomaceous earth residue, although the compressive strength results of the mortars were slightly lower than those for mortars prepared with RHA or commercial reagents
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