Heat transport with advection in fractured rock

In the transport of heat in porous media, diffusion generally dominates over advection due to slow fluid velocities imposed by low permeability. This is the reason why standard Galerkin formulation leading to extra non-symmetric matrix terms may be still used successfully. However, in the presence of fractures the situation may be different. Fractures constitute preferential flow paths where fluid velocities may be significant and advection may become dominant over diffusion (“large advection” with Péclet number >1). This paper focuses on the formulation, numerical implementation and verification of a model to solve the steady-state heat transport problem with large advection along geomechanical discontinuities represented by zero-thickness interface elements. The fluid velocity field is considered as known input data (no hydraulic coupling). The existing SUPG method is modified for its application to zero-thickness interface elements, and the resulting formulation is implemented in an existing FE geomechanical code. An example of application is presented with large advection along a discontinuity crossing a low permeability domain. The results show that the proposed approach leads to stable results, in contrast to standard Galerkin

Estudio del appel de los linfocitos gamma-delta en la enfermedad de Crohn

La EII es un proceso inflamatorio crónico y recidivante de carácter sistémico que afecta predominantemente al tracto gastrointestinal, asociándose frecuentemente con manifestaciones extraintestinales . Existen dos subtipos principales de EII: la enfermedad de Crohn (EC) y la colitis ulcerosa (CU). La EC puede afectar cualquier parte del tracto digestivo, es de carácter transmural y suele afectar a individuos jóvenes, alternando periodos de remisión clínica y brotes de actividad. El control clínico de estos brotes recidivantes requiere el empleo de fármacos antiinflamatorios no exentos de efectos secundarios (corticoides, inmunosupresores, agentes biológicos etc.) siendo frecuente la necesidad de hospitalizaciones e incluso de cirugía para el tratamiento de las complicaciones. La etiopatogenia de la EC es en muchos aspectos desconocida. Actualmente se considera la EII como un trastorno poligénico inmunitario de causa multifactorial en el que intervienen: 1) factores genéticos individuales; 2) factores ambientales; 3) la flora intestinal (microbioma) y 4) la respuesta inmunitaria. Una combinación de estos factores produce una respuesta inmunitaria inadecuada y excesiva contra la flora comensal en sujetos genéticamente predispuestos. Los linfocitos T (LT) pueden dividirse en dos grandes subpoblaciones según el receptor para antígeno que expresan en la membrana de superficie (TCR): los LT αβ y los LT γδ, que expresan el TCR-αβ y el TCR-γδ respectivamente. Tres características fundamentales diferencian a los LTγδ de los LTαβ: 1) Se localizan fundamentalmente en las mucosas constituyendo hasta el 50% de los linfocitos intraepiteliales (LIE) y son escasos en sangre periférica y órganos linfoides secundarios, donde predominan los LTαβ ; 2) reconocen proteínas directamente sin el procesamiento antigénico previo por las moléculas del complejo mayor de histocompatibilidad (CMH); y 3) son potentemente estimuladas directamente por metabolitos microbianos fosforilados y antígenos lipídicos. Estas células se consideran una pieza clave en la primera línea de defensa contra la invasión de patógenos invasivos (los epitelios), así como en la homeostasis de la respuesta inmune y en el control de las infecciones, los tumores y las enfermedades autoinmunitarias. Actualmente existen varias líneas de investigación empleando estas células como diana terapéutica aprovechando estas características con resultados prometedores. La IL-7 pertenece a la familia de hematopoyetinas de clase 1 (γc), se produce fundamentalmente por las células del estroma no hematopoyéticas y por las células epiteliales de la médula ósea y el timo. Se considera como el factor más importante para la estimulación y homeostasis de los LT en general, y en particular de los linfocitos intraepiteliales (LIEs) y los LTγδ. El presente estudio se propone evaluar y comparar los valores séricos de linfocitos y sus distintas subpoblaciones, y de la IL-7 en 102 pacientes con EC y sujetos sanos, y su variación según las distintas variables clínicas estudiadas. Nuestros resultados confirman la presencia de linfopenia con una deficiencia de LTγδ en sangre periférica en pacientes con EC, corroborando estudios previos, así como su relación inversa con marcadores de actividad clínica y endoscópica, que se mantiene con independencia de la presencia o no de tratamiento y que constituye un nuevo mecanismo patogénico en la enfermedad. Se confirma asimismo la ausencia de una elevación compensatoria de la IL-7 lo que apunta a un posible defecto inmunitario en la regulación de estas células, con posibles implicaciones terapéuticas.Inflammatory bowel disease (IBD) is a chronic relapsing systemic disease, mainly affecting the gastrointestinal tract with extraintestinal manifestations which includes two main conditions: ulcerative colitis (UC) and Crohn´s disease (CD). It affects mainly young individuals, thus requiring the use of anti-inflammatory and immunsupressive drugs for long periods of time, with the subsequent need for specialist controls and the burden of frequent side effects. Moreover, IBD patients frequently require hospitalizations and surgical procedures, impacting directly in the medical associated costs and quality of life. The increasing incidence and prevalence of the disease and its unknown exact pathogenesis has raised the interest of an increasingly diverse group of clinicians and research groups, reinforcing the need for translational and multidisciplinary approaches. It is well recognized that an altered immune reponse to commensal intestinal bacteria takes place in genetically predisposed individuals, and it can be considered an immune deficiency condition. Attempts to bolster and regulate immunity (especially the T lymphocytes) and/or correct the immunity defects to prevent chronic inflammation represents a change of paradigme from conventional anti-inflammatory treatments to immunotherapy, that has showed positive results in other autoimmune and infectious diseases and cancer. Thus, the study of these immunological alterations, and specifically, the role of lymphocytes and their regulators in IBD, is a key element for understanding its pathogenesis, and develop new and more effective therapeutic alternatives. There are two T lymphocyte populations that can be distinguished by the expression of αβ or γδ chains. αβ T lymphocytes (αβTL) are more frequent (90-95%) in the peripheral blood, spleen and lymph nodes. On the other hand, γδ T lymphocytes (γδTL) constitute only a small proportion (1-5%) of the lymphocytes that circulate in the blood and peripheral organs, and they are present mainly in the epithelia, where they can constitute up to 50% of intraepithelial T lymphocytes (IELs). There are two major features that make γδTL different from the αβ subtype: 1)γδ TL can recognize antigens without the normal constraints of antigen processing and presentation (Major Histocompatibility Complex -MHC- restriction), providing a direct and quick response; 2)γδ TL can recognize non peptide ligands like viral proteins, bacterial superantigens, or heat shock proteins and are highly stimulated by phosphoantigens. These special features allow γδ TL to provide a comprehensive response for pathogen clearance through direct recognition, to collaborate intensely in immune modulation and in wound healing mechanisms. Interleukin 7 (IL-7) belongs to the class 1 of cytokines that signal through the common heterodimeric γc chain and has been recognized as a mediator of the homeostatic mechanisms that maintains a stable number of naive memory T cells in the peripheral immune system. Moreover IL-7 is absolutely critical for the development of γδTL, and γδTL cannot be detected in IL-7R α knockout mice. These potent immunological homeostatic properties and particularly its unique capacity of expanding naive T lymphocyte pools, make IL-7 a promising candidate for treating conditions causing T lymphocyte dysfunction or lymphopenia like chronic viral infections (HIV, CMV), regeneration of T cells after hematopoietic stem cell transplant, immunodeficiencies, autoimmune disorders and cancer immunotherapy. This could also be the case in IBD. Our hypothesis is that IBD patients present an alteration in the innate immunity, specifically in the function of γδTL and its main regulator IL-7, that contributes to the initiation and/or perpetuation of the intestinal inflammation. We aimed to determine the levels of γδTL and IL-7 in peripheral blood of 102 Crohn´s disease patients and controls and analyse its relation with several clinical and endoscopiacal variables. Our results show a decrease in the overall lymphocyte population and specially in γδTL in the peripheral blood of patients with CD. This decrease occurred in all different clinical settings and was inversely correlated with the clinical and endoscopical activity. We also found a surprising decreased level of serum IL-7 in CD –although not statistically significative- (high compensating IL-7 levels were expected due to lymphopenia). This results represents a new pathogenic mechanism in CD, with potential therapeutical implications

Condition Indices and their Relationship with Environmental Factors in Fish Larvae

Memoria de tesis doctoral presentada por Ignacio Alberto Catalán Alemany para obtener el título de Doctor en Biología por la Universitat de Barcerlona (UB), realizada bajo la dirección de la Dra. María Pilar Olivar Buera del Institut de Ciències del Mar (ICM-CSIC)[EN] This thesis is organised in four main chapters. The first chapter is devoted to a general introduction and objectives. Number two is devoted to all the work developed in the laboratory. Chapter three embraces all the work that was done with field data. Each of these two central chapters collects a mixture of published and row material. In the sake of clarity, all the thesis has been written in the same format, regardless the state of publication of the information. If the information of a particular section has been published, it is indicated at the beginning of the section. Information which is considered important but which was not included in a particular published section, has been inserted after authors’ approval. A brief introduction and extensive discussion is given in each of the sections conforming chapters two and three. In chapter four, the main conclusions from each part are summarised. Provided that the thesis is organised in a similar way that a compendium of publications, and as a guide to the reader, the repetition of some material at the introduction was unavoidable[ES] Esta tesis se organiza en cuatro capítulos principales. El primer capítulo ofrece una introducción y objetivos generales. El segundo contiene la información obtenida de la experimentación en laboratorio. El tercer capítulo está dedicado a los estudios de campo. Cada uno de estos capítulos centrales se organiza en secciones. La información que contienen son una mezcla de material publicado e inédito. Todas las secciones se han escrito en un formato similar para facilitar la comprensión. Si una sección o parte de ella ha sido publicada, la referencia se señala al principio de la sección correspondiente. En los casos en que la información publicada ha sido ampliada, se ha obtenido el consentimiento de los autores de la publicación. En cada sección de los capítulos centrales se ha añadido una introducción y una discusión. En el capítulo cuarto se recogen las conclusiones generales de la tesis. Dado que la estructura de las seccciones es similar a la de un artículo, fue inevitable incluir, en algún caso, información redundanteLa realización de esta tesis ha recibido el soporte económico de la Comisión Interministerial de Ciencia y Tecnología (Proyecto MAR 97-0902 CICYT)Peer Reviewe

Heat transport with advection in fractured rock

In the transport of heat in porous media, diffusion generally dominates over advection due to slow fluid velocities imposed by low permeability. This is the reason why standard Galerkin formulation leading to extra non-symmetric matrix terms may be still used successfully. However, in the presence of fractures the situation may be different. Fractures constitute preferential flow paths where fluid velocities may be significant and advection may become dominant over diffusion (“large advection” with Péclet number >1). This paper focuses on the formulation, numerical implementation and verification of a model to solve the steady-state heat transport problem with large advection along geomechanical discontinuities represented by zero-thickness interface elements. The fluid velocity field is considered as known input data (no hydraulic coupling). The existing SUPG method is modified for its application to zero-thickness interface elements, and the resulting formulation is implemented in an existing FE geomechanical code. An example of application is presented with large advection along a discontinuity crossing a low permeability domain. The results show that the proposed approach leads to stable results, in contrast to standard Galerkin.Postprint (published version

Estudio de diagnosis de eficiencia energética del alumbrado público en el Ayuntamiento de Canfranc

El objeto de este proyecto es la realización de una diagnosis energética del sistema de alumbrado público del municipio de Canfranc, en la provincia de Huesca, con el fin de realizar propuestas para una gestión más eficiente del mismo. Se realiza una diagnosis del consumo de energía eléctrica en las instalaciones de alumbrado exterior de las vías públicas de Canfranc. Este municipio se encuentra dividido en dos núcleos urbanos: Canfranc Pueblo y Canfranc Estación, por tanto, el estudio se llevará a cabo sobre la totalidad del alumbrado de ambos núcleos urbanos

Transient large heat advection in fractured rock: a zero-thickness interface formulation

In a fractured rock mass, the existence of discontinuities may generate preferential paths where the hydraulic flow velocities are frequently much higher than in the porous medium and heat advection tends to dominate over heat diffusion. In these cases, the standard Galerkin FEM method leads to oscillatory results and requires the use of stabilization methods. Thus, the current paper introduces a 3-D formulation to solve the large advection problem for zero-thickness interface elements –which may be used to discretize fractures in a FEM context–, based on a pre-existent Characteristic method. A verification example is presented, showing that the formulation exhibits a good performance to represent the heat transport by the fluid along zero-thickness interface elements.This work was partially supported by research grant BIA2016-76543-R from MEC (Madrid), which includes European FEDER funds, and 2017SGR-1153 from Generalitat de Catalunya (Barcelona). The first author also acknowledges his FPU scholarship from MEC (Madrid).Postprint (published version

Changes in the juvenile fish assemblage of a Mediterranean shallow Posidonia oceanica seagrass nursery area after half a century

The within-year dynamics of the juvenile fish community in a shallow seagrass-dominated nursery habitat (Posidonia oceanica) in a Mediterranean bay were compared between two surveys separated by 50 years (1960 and 2012-2013). A nocturnal survey over depths ranging from 2 to 10 m over patchy seagrass meadows was conducted for one year (2012-2013) through 72 epibenthic tows spread fortnightly in 4 nearby stations, mimicking a survey conducted in 1960 in terms of sampling intensity, sampling zone, temporal coverage and sampling gear. Although a large proportion of the fish species were similar among surveys, remarkable and statistically significant differences were detected. A striking feature was that one of the most common and abundant Sparidae species currently, Diplodus annularis, did not appear in 1960. Other strong differences included the nonappearance of the European eel Anguilla anguilla in the recent survey. Furthermore, one of the most valuable species for artisanal fisheries in the area, the black scorpionfish Scorpaena porcus, was almost 10 times less abundant in 1960. A finer-scale study of the 2012-2013 survey allowed a quantitative analysis between species composition and potential environmental drivers through redundancy analysis that well described the current pattern of time-dependent recruitment pulses in nearshore meadows of the area throughout the year, with marked effects of surface temperature and photoperiod. The comparison between surveys suggests that some major differences between surveys are not likely to be attributable to interannual stochasticity in recruitment or environmental variability but may be related to i) unaccounted-for habitat transformation and/or ii) the strong decrease in juvenile fishing mortality in this shallow nursery area since the enforcement of bans on littoral epibenthic trawling activities characteristic of this area

Dieta de las larvas de albacora Thunnus alalunga (Bonnaterre, 1788) en aguas de Mallorca (Mediterráneo NW)

These are the first data on the feeding of larval albacore (Thunnus alalunga Bonnaterre, 1788) in the Mediterranean. Specimens were gathered from day-time bongo-hauls conducted over the SW Mallorcan (Balearic Islands) shelf-slope. Ninety eight percent of 101 individuals ranging from 2.65 to 9.4 mm standard length (SL) contained 1 to 15 prey items per gut. Mean number of prey/gut was 3.55 ± 2.19 (SD). A positive correlation was found between larval SL and the number of prey/gut. The analysis of frequency of occurrence (F), numerical frequency (N), weight frequency (W) and the Index of Relative Importance (IRI) showed a dominance of copepodites and nauplii in the smallest size-class. As larvae grew, cladocerans and Calanoida copepodites dominated the diet, and cladocerans and copepodites were important in F, N and W. Piscivory was observed after notochord flexion and was important in terms of W. A positive correlation between mean prey size and both SL and lower jaw length (LJL) was observed. The niche breadth (S) did not vary with LJL, but the raw prey size range did. Larger copepodites, the absence of nauplii and the incorporation of fish larvae and a larger number of cladocerans in the diet accounted for the increase in mean prey size through increased larval size.Se ofrecen los primeros datos sobre la dieta de las larvas de albacora (Thunnus alalunga Bonaterre, 1788) en el Mediterráneo. Los especímenes se obtuvieron de pescas diurnas con bongo sobre la plataforma-talud al SW de Mallorca (Islas Baleares). El 98% de 101 individuos de entre 2.65 y 9.4 mm de longitud estándar (LE) contuvieron entre 1 y 15 presas por digestivo. La media de presas por larva fue de 3.55 ± 2.19 (DE), existiendo una correlación positiva entre el número de presas en el tubo digestivo y la LS. Los índices de frecuencia de ocurrencia (F), frecuencia numérica (N), frecuencia en peso (W) y el Índice de Importancia Relativa (IRI) mostraron un predominio de copepoditos y nauplius en larvas pequeñas, disminuyendo en importancia a lo largo del crecimiento en detrimento de cladóceros y copepoditos de Calanoida, que fueron importantes en F, N y W. Se observó piscivoría, importante en W, a partir de la flexión de la notocorda. Se detectó una correlación positiva entre el tamaño medio de las presas y tanto la LS como la longitud de la maxila (LJL) de las larvas. La amplitud del nicho alimentario (S) no varió con la LJL, aunque el rango total del tamaño de las presas sí lo hizo. El aumento de talla de los copepoditos, la desaparición progresiva de mauplius y la incorporación de larvas de peces y más cladóceros explica el aumento de la talla media de las presas a lo largo del crecimiento larvario

El papel de la velocidad oceánica en la variabilidad de la clorofila. Un estudio de modelado en el mar de Alborán

In this work we focus on the Alboran Sea (western Mediterranean) to relate wind field and ocean velocity variability with chlorophyll a (Chl a) behaviour, using a 2-km resolution, coupled 3D ocean circulation-NPZD model (ROMS). The analysis is done in three steps. First, we split the seasonal and residual contribution for the fields under study. Second, we calculate the corresponding empirical orthogonal functions (EOFs) for the seasonal and residual parts. Finally, we relate each pair of variables for both seasonal and residual contribution EOFs. The results reported here allow the links between wind and Chl a to be quantified. We explain these links in terms of the ocean velocity field acting as a driver of Chl a variability. The results show that, although the seasonal part of the Chl a field is modulated by the vertical velocity, the residual component is modulated by the horizontal velocity components. Vertical velocities are responsible, through coastal upwelling, for Chl a bloom enhancement, while horizontal velocities spread coastal Chl a surface blooms off-shore.En este trabajo nos centramos en el mar de Alborán (Mediterráneo Occidental) para relacionar los campos de velocidad del viento y del océano con la variabilidad de la clorofila a (Chl a), utilizando un modelo de circulación 3D-NPZD (ROMS-Fennel) con una resolución de 2 km. El análisis se realiza en tres pasos. En primer lugar, separamos la contribución estacional y el residuo para todos los campos de estudio. En segundo lugar, calculamos las correspondientes funciones ortogonales empíricas (EOFs) para las components estacionales y residuales. Por último, relacionamos cada par de variables para ambos, EOFs estacionales y residuales. Los resultados permiten la cuantificación de las relaciones entre el viento y la clorofila. Explicamos estas relaciones en términos del campo de velocidades del océano que actúa como motor de la variabilidad de la Chl a. Los resultados muestran que, aunque la parte estacional de campo Chl a es modulada por la velocidad vertical, la componente residual es modulada por las componentes de la velocidad horizontal. Las velocidades verticales son responsables, a través de la surgencia costera, de incrementar el valor de la proliferación de Chl a, mientras que las velocidades horizontales extienden estas proliferaciones costeras superficiales a mar abierto