Linking biofilm spatial structure to real-time microscopic oxygen decay imaging

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Biofouling on 2018, available online at: http://www.tandfonline.com/10.1080/08927014.2017.1423474Two non-destructive techniques, confocal laser scanning microscopy (CLSM) and planar optode (VisiSens imaging), were combined to relate the fine-scale spatial structure of biofilm components to real-time images of oxygen decay in aquatic biofilms. Both techniques were applied to biofilms grown for seven days at contrasting light and temperature (10/20°C) conditions. The geo-statistical analyses of CLSM images indicated that biofilm structures consisted of small (~100 µm) and middle sized (~101 µm) irregular aggregates. Cyanobacteria and EPS (extracellular polymeric substances) showed larger aggregate sizes in dark grown biofilms while, for algae, aggregates were larger in light-20°C conditions. Light-20°C biofilms were most dense while 10°C biofilms showed a sparser structure and lower respiration rates. There was a positive relationship between the number of pixels occupied and the oxygen decay rate. The combination of optodes and CLMS, taking advantage of geo-statistics, is a promising way to relate biofilm architecture and metabolism at the micrometric scale.Peer ReviewedPostprint (author's final draft

Linking biofilm spatial structure to real-time microscopic oxygen decay imaging

Two non-destructive techniques, confocal laser scanning microscopy (CLSM) and planar optode (VisiSens imaging), were combined to relate the fine-scale spatial structure of biofilm components to real-time images of oxygen decay in aquatic biofilms. Both techniques were applied to biofilms grown for seven days at contrasting light and temperature (10/20°C) conditions. The geo-statistical analyses of CLSM images indicated that biofilm structures consisted of small (~100 µm) and middle sized (~101 µm) irregular aggregates. Cyanobacteria and EPS (extracellular polymeric substances) showed larger aggregate sizes in dark grown biofilms while, for algae, aggregates were larger in light-20°C conditions. Light-20°C biofilms were most dense while 10°C biofilms showed a sparser structure and lower respiration rates. There was a positive relationship between the number of pixels occupied and the oxygen decay rate. The combination of optodes and CLMS, taking advantage of geo-statistics, is a promising way to relate biofilm architecture and metabolism at the micrometric scale

A mechanistic model (BCC-PSSICO) to predict changes in the hydraulic properties for bio-amended variably saturated soils

This is the peer reviewed version of the following article: [Carles Brangarí, A., X. Sanchez-Vila, A. Freixa, A. M. Romaní, S. Rubol, and D. Fernàndez-Garcia (2017), A mechanistic model (BCC-PSSICO) to predict changes in the hydraulic properties for bio-amended variably saturated soils, Water Resour. Res., 53, 93–109, doi:10.1002/2015WR018517], which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/2015WR018517/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.The accumulation of biofilms in porous media is likely to influence the overall hydraulic properties and, consequently, a sound understanding of the process is required for the proper design and management of many technological applications. In order to bring some light into this phenomenon we present a mechanistic model to study the variably saturated hydraulic properties of bio-amended soils. Special emphasis is laid on the distribution of phases at pore-scale and the mechanisms to retain and let water flow through, providing valuable insights into phenomena behind bioclogging. Our approach consists in modeling the porous media as an ensemble of capillary tubes, obtained from the biofilm-free water retention curve. This methodology is extended by the incorporation of a biofilm composed of bacterial cells and extracellular polymeric substances (EPS). Moreover, such a microbial consortium displays a channeled geometry that shrinks/swells with suction. Analytical equations for the volumetric water content and the relative permeability can then be derived by assuming that biomass reshapes the pore space following specific geometrical patterns. The model is discussed by using data from laboratory studies and other approaches already existing in the literature. It can reproduce (i) displacements of the retention curve toward higher saturations and (ii) permeability reductions of distinct orders of magnitude. Our findings also illustrate how even very small amounts of biofilm may lead to significant changes in the hydraulic properties. We, therefore, state the importance of accounting for the hydraulic characteristics of biofilms and for a complex/more realistic geometry of colonies at the pore-scale.Peer ReviewedPostprint (author's final draft

Los equipos docentes en la educación superior ¿Utopía o realidad?

Resumen: La organización académica de los grados universitarios, en el marco del Espacio Europeo de Educación Superior, ha facilitado la constitución de equipos docentes (Zabalza, 2009; López, 2007). Este es uno de los puntos clave en los procesos de organización y mejora (Lester y Evans, 2009; Bacharach, Washut y Dahlberg, 2008) de la enseñanza universitaria, pero a la vez, un tema pendiente por la dificultad en conseguir un cambio de cultura del profesorado, enmarcado a su vez en estructuras poco ágiles y flexibles. El artículo explica una investigación realizada a un grupo de profesores universitarios, con el objetivo de realizar un diagnóstico de la situación de los equipos docentes entre los cursos 2009-2010 al 2011-2012. La metodología usada fue la encuesta, utilizando el cuestionario y el focus group como técnicas de obtención de información. Los resultados muestran que la organización en equipos docentes es una realidad percibida positivamente por el profesorado aunque con problemas y retos que indican el camino que queda aún por recorrer. Summary The academic organization of university degrees, in the frame of the European Higher Education Area, has facilitated the constitution of teachers' teams (Zabalza, 2009; Lopez, 2007). This is one of the key points in the processes of organization and improvement (Lester and Evans, 2009; Bacharach, Washut and Dahlberg, 2008) of higher education, but simultaneously, a hanging topic for the difficulty in obtaining a culture's change of university teachers, also demarcated in slightly agile and flexible structures. The paper is focused in a research caught out a group of university teachers, with the aim to realize a diagnosis of the situation of the teachers' teams between the courses 2009-2010 to 2011-2012. The methodology used was the survey, with questionnaire and focus group. The results show that the organization in teachers teams is a reality perceived positively by teachers, but with problems and challenges that we have still further to go

A mechanistic model (BCC-PSSICO) to predict changes in the hydraulic properties for bio-amended variably saturated soils

The accumulation of biofilms in porous media is likely to influence the overall hydraulic properties and, consequently, a sound understanding of the process is required for the proper design and management of many technological applications. In order to bring some light into this phenomenon we present a mechanistic model to study the variably saturated hydraulic properties of bio-amended soils. Special emphasis is laid on the distribution of phases at pore-scale and the mechanisms to retain and let water flow through, providing valuable insights into phenomena behind bioclogging. Our approach consists in modeling the porous media as an ensemble of capillary tubes, obtained from the biofilm-free water retention curve. This methodology is extended by the incorporation of a biofilm composed of bacterial cells and extracellular polymeric substances (EPS). Moreover, such a microbial consortium displays a channeled geometry that shrinks/swells with suction. Analytical equations for the volumetric water content and the relative permeability can then be derived by assuming that biomass reshapes the pore space following specific geometrical patterns. The model is discussed by using data from laboratory studies and other approaches already existing in the literature. It can reproduce (i) displacements of the retention curve toward higher saturations and (ii) permeability reductions of distinct orders of magnitude. Our findings also illustrate how even very small amounts of biofilm may lead to significant changes in the hydraulic properties. We, therefore, state the importance of accounting for the hydraulic characteristics of biofilms and for a complex/more realistic geometry of colonies at the pore-scale

El hacer del equipo docente: de la identidad individual a la colectiva

Los equipos docentes facilitan la construcción de la identidad docente y el desarrollo de la docencia. La investigación que se presenta tiene como finalidad identificar los elementos del hacer de los equipos docentes que potencian su carácter funcional y permiten tejer una identidad colectiva. Los resultados muestran estos elementos que definen el hacer colectivo que va desde el conocerse, reconocerse, definir un proyecto, deliberar para innovar y avaluarse

Quality and reactivity of dissolved organic matter in a Mediterranean river across hydrological and spatial gradients.

Understanding DOM transport and reactivity in rivers is essential to having a complete picture of the global carbon cycle. In this study, we explore the effects of hydrological variability and downstream transport on dissolved organic matter (DOM) dynamics in a Mediterranean river. We sampled the main stem of the river Tordera from the source to the sea, over a range of fifteen hydrological conditions including extreme events (flood and drought). By exploring spatial and temporal gradients of DOM fluorescence properties, river hydrology was found to be a significant predictor of DOM spatial heterogeneity. An additional space-resolved mass balance analysis performed on four contrasting hydrological conditions revealed that this was due to a shift in the biogeochemical function of the river. Flood conditions caused a conservative transport of DOM, generating a homogeneous, humic-like spatial profile of DOM quality. Lower flows induced a non-conservative, reactive transport of DOM, which enhanced the spatial heterogeneity of DOM properties. Moreover, the downstream evolution of DOM chemostatic behaviour revealed that the role of hydrology in regulating DOM properties increased gradually downstream, indicating an organised inter-dependency between the spatial and the temporal dimensions. Overall, our findings reveal that riverine DOM dynamics is in constant change owing to varying hydrological conditions, and emphasize that in order to fully understand the role of rivers in the global carbon cycle, it is necessary to take into account the full range of hydrological variability, from floods to droughts

NEU screen shows high accuracy in detecting cognitive impairment in older persons living with HIV

The NEUrocognitive (NEU) Screen is a practical tool proposed to screen for HIV-associated cognitive impairment in the clinical setting. This is a pencil-and-paper method that can be applied rapidly (<=10 minutes for administration) and has no copyright limitations. In this study, we aimed at investigating its diagnostic accuracy in an older population of persons living with HIV (PLWH), with cutoffs set at 30, 40, 50, and 60 years. Data were collected from a sample of 368 PLWH who underwent a comprehensive neuropsychological tests battery (gold standard). Results of statistical tests showed that accuracy of the NEU Screen increased with age of the participants. The highest degree of precision, with a sensitivity of 91% and specificity of 92%, was obtained for people ages 60 years or older (correct classification: 91%). These optimal results point to the great potential of the NEU Screen as a tool for detecting cognitive disorders in older PLWH

Restrained Eating Is Associated with Lower Cortical Thickness in the Inferior Frontal Gyrus in Adolescents

Some eating patterns, such as restrained eating and uncontrolled eating, are risk factors for eating disorders. However, it is not yet clear whether they are associated with neurocognitive differences. In the current study, we analyzed whether eating patterns can be used to classify participants into meaningful clusters, and we examined whether there are neurocognitive differences between the clusters. Adolescents (n = 108; 12 to 17 years old) and adults (n = 175, 18 to 40 years old) completed the Three Factor Eating Questionnaire, which was used to classify participants according to their eating profile using k means clustering. Participants also completed personality questionnaires and a neuropsychological examination. A subsample of participants underwent a brain MRI acquisition. In both samples, we obtained a cluster characterized by high uncontrolled eating patterns, a cluster with high scores in restrictive eating, and a cluster with low scores in problematic eating behaviors. The clusters were equivalent with regards to personality and performance in executive functions. In adolescents, the cluster with high restrictive eating showed lower cortical thickness in the inferior frontal gyrus compared to the other two clusters. We hypothesize that this difference in cortical thickness represents an adaptive neural mechanism that facilitates inhibition processes

La formació inicial dels futurs agents socioeducatius davant la diversitat religiosa i cultural

En l’actualitat en el context català es dibuixa una realitat cultural diversa que comporta també un mapa de religions divers. Aquesta realitat és un repte per la convivència en l’espai públic, i així mateix un repte per l’educació i pels futurs educadors. El marc escolar públic, com a espai privilegiat on conviuen cultures i religions, ha de respondre a una sèrie de principis i fonaments que potenciïn el diàleg intercultural i interreligiós. En aquesta gran responsabilitat, la formació inicial i contínua dels docents que ho protagonitzen esdevé essencial. El projecte que aquí es presenta pretén posar l’accent en una part fonamental d’aquesta formació dels futurs docents: les seves actituds davant de la necessària gestió de la diversitat religiosa i cultural que es trobaran a les seves aules i espais educatius. Qüestionem si aquestes actituds responen exactament als requeriments que s’espera d’una escola laica però que gestiona la diversitat religiosa i cultural del seu alumnat i famílies, i quins elements explicatius es donen en aquestes actituds. Per aquest motiu es planteja un estudi diagnòstic en profunditat sobre les actituds dels estudiants de Formació del Professorat, Educació Social i Pedagogia de les universitats públiques catalanes: Universitat de Barcelona, Universitat Autònoma de Barcelona, Universitat Rovira i Vigili, Universitat de Girona i Universitat de Lleida. Aquest estudi, de disseny metodològic mixt pretén, mitjançant un estudi per enquesta de caràcter quantitatiu identificar els elements clau en aquestes actituds, considerant el seu perfil digital i la seva formació i experiència en interculturalitat. Aquest estudi obrirà nous interrogants als que respondre mitjançant tècniques qualitatives com el grup de discussió que, segons els perfils identificats, pot contribuir a la comprensió del grau d’actitud dels estudiants vers el diàleg intercultural i interreligiós; i la seva gestió des de l’educació.Direcció general d'Afers Religiosos. Generalitat de Cataluny