9,722 research outputs found

    Debates—Stochastic subsurface hydrology from theory to practice: why stochastic modeling has not yet permeated into practitioners?

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    This is the peer reviewed version of the following article: [Sanchez-Vila, X., and D. Fernàndez-Garcia (2016), Debates—Stochastic subsurface hydrology from theory to practice: Why stochastic modeling has not yet permeated into practitioners?, Water Resour. Res., 52, 9246–9258, doi:10.1002/2016WR019302], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/2016WR019302/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingWe address modern topics of stochastic hydrogeology from their potential relevance to real modeling efforts at the field scale. While the topics of stochastic hydrogeology and numerical modeling have become routine in hydrogeological studies, nondeterministic models have not yet permeated into practitioners. We point out a number of limitations of stochastic modeling when applied to real applications and comment on the reasons why stochastic models fail to become an attractive alternative for practitioners. We specifically separate issues corresponding to flow, conservative transport, and reactive transport. The different topics addressed are emphasis on process modeling, need for upscaling parameters and governing equations, relevance of properly accounting for detailed geological architecture in hydrogeological modeling, and specific challenges of reactive transport. We end up by concluding that the main responsible for nondeterministic models having not yet permeated in industry can be fully attributed to researchers in stochastic hydrogeology.Peer ReviewedPostprint (author's final draft

    Stochastic estimation of hydraulic transmissivity fields using flow connectivity indicator data

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    This is the peer reviewed version of the following article: [Freixas, G., D. Fernàndez-Garcia, and X. Sanchez-Vila (2017), Stochastic estimation of hydraulic transmissivity fields using flow connectivity indicator data, Water Resour. Res., 53, 602–618, doi:10.1002/2015WR018507], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/2015WR018507/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Most methods for hydraulic test interpretation rely on a number of simplified assumptions regarding the homogeneity and isotropy of the underlying porous media. This way, the actual heterogeneity of any natural parameter, such as transmissivity ( math formula), is transferred to the corresponding estimates in a way heavily dependent on the interpretation method used. An example is a long-term pumping test interpreted by means of the Cooper-Jacob method, which implicitly assumes a homogeneous isotropic confined aquifer. The estimates obtained from this method are not local values, but still have a clear physical meaning; the estimated math formula represents a regional-scale effective value, while the log-ratio of the normalized estimated storage coefficient, indicated by math formula, is an indicator of flow connectivity, representative of the scale given by the distance between the pumping and the observation wells. In this work we propose a methodology to use math formula, together with sampled local measurements of transmissivity at selected points, to map the expected value of local math formula values using a technique based on cokriging. Since the interpolation involves two variables measured at different support scales, a critical point is the estimation of the covariance and crosscovariance matrices. The method is applied to a synthetic field displaying statistical anisotropy, showing that the inclusion of connectivity indicators in the estimation method provide maps that effectively display preferential flow pathways, with direct consequences in solute transport.Peer ReviewedPostprint (published version

    Jacaranda House - Natural Park of Cabo de Gata-NĂ­jar, AlmerĂ­a. Spain

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    [EN] The article exposes the creative, design and phenomenological process of the project design and construction of the Jacaranda House (2016-2018), a single-family exempt house located in the Natural Park of Cabo de Gata-Níjar, in Almería. Jacaranda House is built with an exposed concrete structure and formwork using the traditional system of wooden boards. In addition, the walls are built with rustic brick in some of its exterior faces. Jacaranda House work aims to presents itself as if it was an inhabited structure, an infrastructure arranged on the desert landscape of Cabo de Gata. The formal abstraction of this landscape coexists with the organicism with which the terracing of the plot and the garden is resolved. The following article is developed with the help of the plans, drawings and diagrams, as well as the final photographs and images of the construction process. A brief theoretical and historical reflection on the use of exposed concrete in domestic architecture will be linked to the description of the construction job.[ES] El artículo expone el proceso creativo, proyectual y de concepción fenomenológica del proyecto y construcción de la Casa Jacaranda (2016-2018), una vivienda unifamiliar exenta situada en el Parque Natural de Cabo de Gata-Níjar, en Almería. Se trata de una casa construida de hormigón visto encofrado mediante el sistema tradicional de tablas de madera, además de ladrillo rústico de tejar que se usa en alguno de sus paños exteriores. La obra pretende presentarse como si se tratara de una estructura habitada, como una infraestructura dispuesta sobre el paisaje desértico. Mediante los planos, fotografías finales, fotografías del proceso constructivo, dibujos y esquemas se desarrollará un artículo donde la descripción de la obra se engarzará con una reflexión teórica e histórica sobre el uso del hormigón visto en la arquitectura doméstica.García-Sánchez, J. (2020). Casa Jacaranda - Parque natural de Cabo de Gata-Níjar, Almería. España. En IX Congreso Internacional Arquitectura Blanca. Editorial Universitat Politècnica de València. https://doi.org/10.4995/CIAB9.2020.10657OC

    Spaniards First. Notes on Hate Speech towards Migrants on Twitter

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    En un contexto político de gran polarización ideológica como el actual,en el que nacen nuevos partidos populistas, resulta crucial atender a los mensajesde odio difundidos a través de los medios de comunicación, y especialmente, deTwitter, que se ha convertido en fuente primaria de información para millonesde personas. El presente artículo está dedicado a analizar el lenguaje xenófobo yracista a partir de un corpus compuesto por una selección de respuestas en la redde microblogging a la cuenta oficial del partido Vox. Nuestro propósito es doble:por un lado, sondearemos los marcos conceptuales más frecuentes que articulanel lenguaje de la extrema derecha y que calan entre los más jóvenes; por otro,trataremos de buscar la correlación entre esos marcos y los que partidos populistas como Vox retroalimentan a través de Twitter

    Reproductive biology of "Helianthemum apennium" (L.) Mill. and "H. caput-felis" Boiss. (Cistaceae) from Mallorca (Balearic Island, Spain)

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    El estudio de la biología reproductiva de poblaciones naturales de Helianthemum apenninum y H. caput-felis en Mallorca ha demostrado que son básicamente entomófilos, aunque también producen numerosos frutos por auto-polinización. Las flores de H. caput-felis duran cuatro dias, mientras que las de H.apenninum duran uno, como suele ocurrir en otras especies del género. En la población de H. apenninum, la predación por ungulados afecta al 50% de los individuos. Los test de germinación mostraron una temperatura óptima de germinación de 16 ºC para H. apenninum y de 23ºC para H. caput-felis. H. caput-felis muestra una importante variabilidad interanual en su comportamiento germinativo. En las poblaciones naturales de H. caput-felis, se ha observado atelecoria, y en relación con ésta, las semillas germinan dentro de la cápsula

    European island Outermost Regions and climate change adaptation: a new role for regional planning

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    Some European regions are experiencing unprecedented impacts due to climate change. The islands of the Outermost Regions are also being affected by this phenomenon. When these islands have a higher level of functional complexity, climate change increases the difficulty of defining their urban and regional planning tools. A comparative analysis of the characteristics of these islands (comparing land use and demographic density) and a review of the efficacy of planning tools for incorporating climate change adaptation has been developed in order to understand the transformations produced in the regulatory frameworks. Through the case studies of Gran Canaria (Spain) and Reunion Island (France), which show high levels of urban and peri-urban land use pressure, the paper focuses on analysing the degree of mainstreaming adaptation strategies, as key elements for land use planning in a context of climate change. Results show a dysfunction between adaptation needs and the incorporation of the climatic issue in land use management. Insular planning tools do not generally consider climate change adaptation and excessive top-down management is observed in the decision-making process. This paper contributes new case studies to the literature, comparing two non-sovereign European islands, and reviews the regulatory framework on adaptation in insular contexts related to climate change

    Choice of Metrics used in Collaborative Filtering and their Impact on Recommender Systems

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    The capacity of recommender systems to make correct predictions is essentially determined by the quality and suitability of the collaborative filtering that implements them. The common memory-based metrics are Pearson correlation and cosine, however, their use is not always the most appropriate or sufficiently justified. In this paper, we analyze these two metrics together with the less common mean squared difference (MSD) to discover their advantages and drawbacks in very important aspects such as the impact when introducing different values of k-neighborhoods, minimization of the MAE error, capacity to carry out a sufficient number of predictions, percentage of correct and incorrect predictions and behavior when attempting to recommend the n-best items. The paper lists the results and practical conclusions that have been obtained after carrying out a comparative study of the metrics based on 135 experiments on the MovieLens database of 100,000 ratios

    Adaptive Comfort Models Applied to Existing Dwellings in Mediterranean Climate Considering Global Warming

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    Comfort analysis of existing naturally ventilated buildings located in mild climates, such as the ones in the Mediterranean zones, offer room for a reduction in the present and future energy consumption. Regarding Spain, most of the present building stock was built before energy standards were mandatory, let alone considerations about global warming or adaptive comfort. In this context, this research aims at assessing adaptive thermal comfort of inhabitants of extant apartments building in the South of Spain per EN 15251:2007 and ASHRAE 55-2013. The case study is statistically representative housing built in 1973. On-site monitoring of comfort conditions and computer simulations for present conditions have been carried out, clarifying the degree of adaptive comfort at present time. After that, additional simulations for 2020, 2050, and 2080 are performed to check whether this dwelling will be able to provide comfort considering a change in climate conditions. As a result, the study concludes that levels of adaptive comfort can be considered satisfactory at present time in these dwellings, but not in the future, when discomfort associated with hot conditions will be recurrent. These results provide a hint to foresee how extant dwellings, and also dwellers, should adapt to a change in environmental conditions

    Biochemical and cytological studies of genetic transfer from the Mv genome of Aegilops ventricosa into hexaploid wheat

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    A double interspecific oross {Triticum turgidum (AB) var. rubroatrum H-l-1 x Ae. ventvicosa (DM°) AP-l} x T.aestivum (ABD) cv. Almatense H-10-1S was carried out in 1950 by M. Alonso Peña (Cuenca, Spain) and 70 Unes were devived from it by vepeated selfing (Unes H-93-1 thvough 70). Pveliminavy biochemical evidence indicated genetic tvansfev fvom the M° genome of Ae.ventvicosa into some of these Unes. A more detailed biochemical and cytological characteriza tion of the H-93- Unes was undertaken. A progress report of these studies is presented here. Fourten biochemical systems, each representing a set of up to 4 homoeologous loci, weve investigated in the vavental material, in the H-93- Unes, and in Ae. squavrosa (DD), Ae. comosa (MM) and Ae. uniaristata (M^-M11). Biochemical markers controlled by the A or B genomes of one or both wheat parents weve distributed in the H-93- Unes as expected if the egcells fvom the self-stevile ABDM0 hybvid, rescued by the ABD polen, cavvied the complete A and B genomes from T. tuvgidum. The distvibution of biochemical mavkevs contvolled by the D genomes of one ov both D genome parents indicated that most of the eggcells from the ABDM0 hybrid carvied most of the D genome, i.e. 3 out of 8 markers of the former tupe were absent in a few Unes each, ind.icating incomplete homology between the two D genomes, non-homologous transfer or deletion. Biochemical characters present in Ae. ventricosa (DM°), Ae. comosa (M), Ae. uniaristata (M11) and absent in T. aestivum (ABD), Ae. squarrosa (D) and T. tuvgidum (AB) were selected as M° genome markers. Two of these markers were not transmited to the H-93- Unes, three were tvansmitted with low fvequency and one with a high fvequency. Resistance to Erisiphe graminis was determined by Dosba and Doussinault at Rennes and was found to be transmitted with low fvequency. Somatic chromosome numbers of the H-93- Unes were counted and all weve found to be hexaploid. Meiosis was studied in Unes cavvying M° genome mavkevs and in their hybrids with the T. aestivum parent, to determine the máximum numbev of alien chvornosornespvesent in each Une. The joint considevation of the biochemical and the cytological evidence se^me to indícate that the genetic tvansfev has taken place by chvomosome substitution and by vecombination

    CaracterizaciĂłn y propiedades de una vermiculita de Badajoz

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    A chemical, thermal and X-ray study about a sample of vermiculite from Badajoz has been carried out. The realized investigations, i. e. chemical analysis, exchangeable cations, cation-exchange capacity, dehydration curve, differential thermal analysis and X-ray study, show that this mineral is a not well crystalized, calcium and magnesium saturated, rather weathered vermiculite.Se ha efectuado un estudio químico y fisicoquímico de una vermiculita de Badajoz. Las determinaciones realizadas, análisis químico, cationes cambiables, capacidad de cambio, curva de deshidratación, análisis térmico diferencial y diagramas de difracción de rayos X, indican que el material investigado es una vermiculita, algo degradada, no muy bien cristalizada, cuyos cationes de cambio son magnesio y calcio, predominando este último
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