64 research outputs found

    A locally adaptive kernel regression method for facies delineation

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    Facies delineation is defined as the separation of geological units with distinct intrinsic characteristics (grain size, hydraulic conductivity, mineralogical composition). A major challenge in this area stems from the fact that only a few scattered pieces of hydrogeological information are available to delineate geological facies. Several methods to delineate facies are available in the literature, ranging from those based only on existing hard data, to those including secondary data or external knowledge about sedimentological patterns. This paper describes a methodology to use kernel regression methods as an effective tool for facies delineation. The method uses both the spatial and the actual sampled values to produce, for each individual hard data point, a locally adaptive steering kernel function, self-adjusting the principal directions of the local anisotropic kernels to the direction of highest local spatial correlation. The method is shown to outperform the nearest neighbor classification method in a number of synthetic aquifers whenever the available number of hard data is small and randomly distributed in space. In the case of exhaustive sampling, the steering kernel regression method converges to the true solution. Simulations ran in a suite of synthetic examples are used to explore the selection of kernel parameters in typical field settings. It is shown that, in practice, a rule of thumb can be used to obtain suboptimal results. The performance of the method is demonstrated to significantly improve when external information regarding facies proportions is incorporated. Remarkably, the method allows for a reasonable reconstruction of the facies connectivity patterns, shown in terms of breakthrough curves performance

    Probabilistic risk analysis of groundwater remediation strategies

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    Heterogeneity of subsurface environments and insufficient site characterization are some of the reasons why decisions about groundwater exploitation and remediation have to be made under uncertainty. A typical decision maker chooses between several alternative remediation strategies by balancing their respective costs with the probability of their success or failure. We conduct a probabilistic risk assessment (PRA) to determine the likelihood of the success of a permeable reactive barrier, one of the leading approaches to groundwater remediation. While PRA is used extensively in many engineering fields, its applications in hydrogeology are scarce. This is because rigorous PRA requires one to quantify structural and parametric uncertainties inherent in predictions of subsurface flow and transport. We demonstrate how PRA can facilitate a comprehensive uncertainty quantification for complex subsurface phenomena by identifying key transport processes contributing to a barrier's failure, each of which is amenable to uncertainty analysis. Probability of failure of a remediation strategy is computed by combining independent and conditional probabilities of failure of each process. Individual probabilities can be evaluated either analytically or numerically or, barring both, can be inferred from expert opinio

    Cambios precoces en la tomografía de coherencia óptica en un niño con maculopatía inducida por puntero láser.

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    Niño de 9 años de edad, que refiere pérdida visual en su ojo derecho, después de jugar con un puntero láser. En la primera exploración (12h después) la agudeza visual (AV) era 0,15, la fóvea presentaba una lesión hipopigmentada, y la tomografía de coherencia óptica (OCT) demuestra la presencia de bandas hiperreflectivas verticales. Al cabo de 6 meses, la AV había mejorado a 0,5 y se aprecia en la OCT un área bien definida de interrupción de la retina externa. Discusión Un inadecuado uso de los punteros láser, puede producir pérdida visual severa e irreversible.pre-print671 K

    Genome sequence reveals that Pseudomonas fluorescens F113 possesses a large and diverse array of systems for rhizosphere function and host interaction

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    Background: Pseudomonas fluorescens F113 is a plant growth-promoting rhizobacterium (PGPR) isolated from the sugar-beet rhizosphere. This bacterium has been extensively studied as a model strain for genetic regulation of secondary metabolite production in P. fluorescens, as a candidate biocontrol agent against phytopathogens, and as a heterologous host for expression of genes with biotechnological application. The F113 genome sequence and annotation has been recently reported.Results: Comparative analysis of 50 genome sequences of strains belonging to the P. fluorescens group has revealed the existence of five distinct subgroups. F113 belongs to subgroup I, which is mostly composed of strains classified as P. brassicacearum. The core genome of these five strains is highly conserved and represents approximately 76% of the protein-coding genes in any given genome. Despite this strong conservation, F113 also contains a large number of unique protein-coding genes that encode traits potentially involved in the rhizocompetence of this strain. These features include protein coding genes required for denitrification,diterpenoids catabolism, motility and chemotaxis, protein secretion and production of antimicrobial compounds and insect toxins.Conclusions: The genome of P. fluorescens F113 is composed of numerous protein-coding genes, not usually found together in previously sequenced genomes, which are potentially decisive during the colonisation of the rhizosphere and/or interaction with other soil organisms. This includes genes encoding proteins involved in the production of a second flagellar apparatus, the use of abietic acid as a growth substrate, the complete denitrification pathway, the possible production of a macrolide antibiotic and the assembly of multiple proteinsecretion systems

    The KiVa antibullying program in primary schools in Chile, with and without the digital game component: study protocol for a randomized controlled trial.

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    BACKGROUND: Bullying is a major problem worldwide and Chile is no exception. Bullying is defined as a systematic aggressive behavior against a victim who cannot defend him or herself. Victims suffer social isolation and psychological maladjustment, while bullies have a higher risk for conduct problems and substance use disorders. These problems appear to last over time. The KiVa antibullying program has been evaluated in Finland and other European countries, showing preventive effects on victimization and self-reported bullying. The aims of this study are (1) to develop a culturally appropriate version of the KiVa material and (2) to test the effectiveness of the KiVa program, with and without the online game, on reducing experiences of victimization and bullying behavior among vulnerable primary schools in Santiago (Chile), using a cluster randomized controlled trial (RCT) design with three arms: (1) full KiVa program group, (2) partial KiVa (without online game) program group and (3) control group. METHODS AND DESIGN: This is a three-arm, single-blind, cluster randomized controlled trial (RCT) with a target enrolment of 1495 4th and 5th graders attending 13 vulnerable schools per arm. Students in the full and partial KiVa groups will receive universal actions: ten 2-h lessons delivered by trained teachers during 1 year; they will be exposed to posters encouraging them to support victims and behave constructively when witnessing bullying; and a person designated by the school authorities will be present in all school breaks and lunchtimes using a visible KiVa vest to remind everybody that they are in a KiVa school. KiVa schools also will have indicated actions, which consist of a set of discussion groups with the victims and with the bullies, with proper follow-up. Only full KiVa schools will also receive an online game which has the aim to raise awareness of the role of the group in bullying, increase empathy and promote strategies to support victimized peers. Self-reported victimization, bullying others and peer-reported bullying actions, psychological and academic functioning, and sense of school membership will be measured at baseline and 12 months after randomization. DISCUSSION: This is the first cluster RCT of the KiVa antibullying program in Latin America. TRIAL REGISTRATION: ClinicalTrials.gov, Identifier: NCT02898324 . Registered on 8 September 2016

    The Gac-Rsm and SadB Signal Transduction Pathways Converge on AlgU to Downregulate Motility in Pseudomonas fluorescens

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    Flagella mediated motility in Pseudomonas fluorescens F113 is tightly regulated. We have previously shown that motility is repressed by the GacA/GacS system and by SadB through downregulation of the fleQ gene, encoding the master regulator of the synthesis of flagellar components, including the flagellin FliC. Here we show that both regulatory pathways converge in the regulation of transcription and possibly translation of the algU gene, which encodes a sigma factor. AlgU is required for multiple functions, including the expression of the amrZ gene which encodes a transcriptional repressor of fleQ. Gac regulation of algU occurs during exponential growth and is exerted through the RNA binding proteins RsmA and RsmE but not RsmI. RNA immunoprecipitation assays have shown that the RsmA protein binds to a polycistronic mRNA encoding algU, mucA, mucB and mucD, resulting in lower levels of algU. We propose a model for repression of the synthesis of the flagellar apparatus linking extracellular and intracellular signalling with the levels of AlgU and a new physiological role for the Gac system in the downregulation of flagella biosynthesis during exponential growth

    Chronicle of an early demise, surname extinction in the fifteenth and the seventeenth centuries

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    This is the Author’s Original Manuscript of an article published by Taylor & Francis in Historical Methods: A Journal of Quantitative and Interdisciplinary History on 2018, available online: http://www.tandfonline.com/10.1080/01615440.2018.1462747It has been amply demonstrated that individuals' reproductive capability is the key explanatory phenomenon for understanding onomastic disappearance during the early modern period. This article analyzes the evolution and consequences of surname extinction in a specific population: Catalonia in the sixteenth and seventeenth centuries. In this article two aspects are examined. First, the observed disappearance of surnames is estimated through historical data collected in the Llibres d'Esposalles (Marriage Books) from 1481 to 1600 at Barcelona Cathedral. Second, the estimated natural extinction of those surnames registered in 1481 is forecast by applying a statistical branching processResearch has been funded by Projects MTM2016-76969-P (Spanish State Research Agency, AEI) and MTM2013-41383-P (Spanish Ministry of Economy, Industry and Competitiveness), both co-funded by the European Regional Development Fund (ERDF), IAP network from Belgian Science Policy. Work of J. Ameijeiras-Alonso has been supported by the Ph.D. Grant BES-2014-071006 from the Spanish Ministry of Economy, Industry and CompetitivenessNO

    Cómo poner puertas al campo : tres revisiones panorámicas sobre el uso de biomarcadores en prevención personalizada de enfermedades crónicas

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    Se incluye PDF de la presentación y vídeo del seminario.El seminario trata de dar respuesta a qué biomarcadores hay disponibles o en desarrollo para la prevención personalizada de enfermedades crónicas en la población general. Las revisiones realizadas resumen las principales características y conclusiones de la bibliografía sobre este tema. Abarca los tres principales grupos de enfermedades crónicas:11 tipos de cáncer, 9 enfermedades cardiovasculares y 7 enfermedades neurodegenerativas.N

    Implicaciones metodológicas e inconsistencias de la Tercera Comunicación Nacional sobre Cambio Climático de Colombia

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    Las Comunicaciones Nacionales sobre Cambio Climático (CNCC) son un mecanismo para que los países informen sus avances en mitigación y adaptación, y constituyen uno de los elementos de base para la política sobre cambio climático a escala nacional. Colombia ha emitido tres CNCC. La tercera plantea un escenario que considera las proyecciones de diversos modelos incluidos en la quinta fase del Proyecto de Comparación de Modelos Acoplados (Coupled Model Intercomparison Project, CMIP), el cual se estima como el promedio de las proyecciones correspondientes a las cuatro trayectorias de concentración representativa (Representative Concentration Pathways,RCP) presentadas en el quinto reporte de evaluación del Panel Intergubernamental sobre Cambio Climático. Cada una de estas RCP representa una trayectoria de concentración de gases de efecto invernadero (GEI) para un escenario particular de crecimiento poblacional, económico y tecnológico que conduce a una posible trayectoria de evolución del sistema climático. En este estudio se comparan las proyecciones presentadas en la Tercera CNCC con las obtenidas directamente de los modelos empleados. Nuestros resultados demuestran que al utilizarse un promedio de RCP se pierden escenarios alternos que podrían ser importantes a la hora de considerar posibles futuros diferentes y anulan la utilidad de plantear diversas trayectorias de emisiones de GEI. Más aun, una comparación entre la Segunda y la Tercera CNCC muestra proyecciones de precipitación opuestas para diferentes regiones del país, lo cual es de particular importancia, pues el escenario de cambio climático planteado en la Tercera CNCC sirve de referencia para la toma de decisiones en materia de cambio climático a nivel nacional

    CIBERER : Spanish national network for research on rare diseases: A highly productive collaborative initiative

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    Altres ajuts: Instituto de Salud Carlos III (ISCIII); Ministerio de Ciencia e Innovación.CIBER (Center for Biomedical Network Research; Centro de Investigación Biomédica En Red) is a public national consortium created in 2006 under the umbrella of the Spanish National Institute of Health Carlos III (ISCIII). This innovative research structure comprises 11 different specific areas dedicated to the main public health priorities in the National Health System. CIBERER, the thematic area of CIBER focused on rare diseases (RDs) currently consists of 75 research groups belonging to universities, research centers, and hospitals of the entire country. CIBERER's mission is to be a center prioritizing and favoring collaboration and cooperation between biomedical and clinical research groups, with special emphasis on the aspects of genetic, molecular, biochemical, and cellular research of RDs. This research is the basis for providing new tools for the diagnosis and therapy of low-prevalence diseases, in line with the International Rare Diseases Research Consortium (IRDiRC) objectives, thus favoring translational research between the scientific environment of the laboratory and the clinical setting of health centers. In this article, we intend to review CIBERER's 15-year journey and summarize the main results obtained in terms of internationalization, scientific production, contributions toward the discovery of new therapies and novel genes associated to diseases, cooperation with patients' associations and many other topics related to RD research
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