132 research outputs found

    Diamond forms during low pressure serpentinisation of oceanic lithosphere

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    Diamond is commonly regarded as an indicator of ultra-high pressure conditions in Earth System Science. This canonical view is challenged by recent data and interpretations that suggest metastable growth of diamond in low pressure environments. One such environment is serpentinisation of oceanic lithosphere, which produces highly reduced CH4-bearing fluids after olivine alteration by reaction with infiltrating fluids. Here we report the first ever observed in situ diamond within olivine-hosted, CH4-rich fluid inclusions from low pressure oceanic gabbro and chromitite samples from the Moa-Baracoa ophiolitic massif, eastern Cuba. Diamond is encapsulated in voids below the polished mineral surface forming a typical serpentinisation array, with methane, serpentine and magnetite, providing definitive evidence for its metastable growth upon low temperature and low pressure alteration of oceanic lithosphere and super-reduction of infiltrated fluids. Thermodynamic modelling of the observed solid and fluid assemblage at a reference P-T point appropriate for serpentinisation (350 °C and 100 MPa) is consistent with extreme reduction of the fluid to logfO2 (MPa) = −45.3 (ΔlogfO2[Iron-Magnetite] = −6.5). These findings imply that the formation of metastable diamond at low pressure in serpentinised olivine is a widespread process in modern and ancient oceanic lithosphere, questioning a generalised ultra-high pressure origin for ophiolitic diamond.European Union (EU)Spanish Projects CGL2015-65824 RTI2018-099157-A-I00 PID2019-105625RB-C21 A.RNM.186.UGR18Spanish Government RYC-2015-17596Mexican research program CONACYT-Ciencia Basica A1-S-14574Mexican research program UNAM-PAPIIT IA-10141

    The yeast Candida albicans has a clonal mode of reproduction in a population of infected human immunodeficiency virus-positive patients

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    To ascertain the population structure of Candida albicans, we have carried out a multilocus enzyme electrophoresis study based on the analysis of 21 gene loci. We have thus characterized 55 strains isolated one each from 55 human immunodeficiency virus-positive patients. There is considerable polymorphism among the strains. A population-genetic analysis indicates that the two fundamental consequences of sexual reproduction (i.e., segregation and recombination) are apparently absent in this population of C. albicans. The population structure of C. albicans appears to be clonal, a state of affairs that has important medical and biological consequences

    Influence of ABO locus on PFA-100 collagen-ADP closure time is not totally dependent on the von willebrand factor. Results of a GWAS on gait-2 project phenotypes

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    (1) Background: In a previous study, we found that two phenotypes related to platelet reactivity, measured with the PFA-100 system, were highly heritable. The aim of the present study was to identify genetic determinants that influence the variability of these phenotypes: Closure time of collagen-ADP (Col-ADP) and of collagen-epinephrine (Col-Epi). (2) Methods: As part of the GAIT-2 (Genetic Analysis of Idiopathic Thrombophilia (2) Project, 935 individuals from 35 large Spanish families were studied. A genome-wide association study (GWAS) with ≈ 10 M single nucleotide polymorphisms (SNPs) was carried out with Col-ADP and Col-Epi phenotypes. (3) Results: The study yielded significant genetic signals that mapped to the ABO locus. After adjusting both phenotypes for the ABO genotype, these signals disappeared. After adjusting for von Willebrand factor (VWF) or for coagulation factor VIII (FVIII), the significant signals disappeared totally for Col-Epi phenotype but only partially for Col-ADP phenotype. (4) Conclusion: Our results suggest that the ABO locus exerts the main genetic influence on PFA-100 phenotypes. However, while the effect of the ABO locus on Col-Epi phenotype is mediated through VWF and/or FVIII, the effect of the ABO locus on Col-ADP phenotype is partly produced through VWF and/or FVIII, and partly through other mechanisms

    The impact of dopaminergic treatment over cognitive networks in Parkinson's disease : Stemming the tide?

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    Altres ajuts: Fundació la Marató de TV3/20142910Dopamine-replacing therapies are an effective treatment for the motor aspects of Parkinson's disease. However, its precise effect over the cognitive resting-state networks is not clear; whether dopaminergic treatment normalizes their functional connectivity-as in other networks- and the links with cognitive decline are presently unknown. We recruited 35 nondemented PD patients and 16 age-matched controls. Clinical and neuropsychological assessments were performed at baseline, and conversion to dementia was assessed in a 10 year follow-up. Structural and functional brain imaging were acquired in both the ON and practical OFF conditions. We assessed functional connectivity in both medication states compared to healthy controls, connectivity differences within participants related to the ON/OFF condition, and baseline connectivity of PD participants that converted to dementia compared to those who did not convert. PD participants showed and increased frontoparietal connectivity compared to controls: a pattern of higher connectivity between salience (SN) and default-mode (DMN) networks both in the ON and OFF states. Within PD patients, this higher SN-DMN connectivity characterized the participants in the ON state, while within-DMN connectivity prevailed in the OFF state. Interestingly, participants who converted to dementia also showed higher SN-DMN connectivity in their baseline ON scans compared to nonconverters. To conclude, PD patients showed higher frontoparietal connectivity in cognitive networks compared to healthy controls, irrespective of medication status, but dopaminergic treatment specifically promoted SN-DM hyperconnectivity

    What does the media say about palliative care? A descriptive study of news coverage in written media in Spain

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    INTRODUCTION: The goal of palliative care (PC) is to improve the quality of life of terminal stage patients and their families. The subject frequently appears in the mass-media and this helps create a socially accepted identity. The aim of this study is to describe and analyse PC related news items appeared in the Spanish written media. METHODOLOGY: A descriptive cross-sectional study was designed. Considering diffusion, scope and the range in editorial policy criteria, four printed newspapers (PN) were selected, together with four exclusively digital media sources (DM). Through Mynews, a newspaper content depository, and the search tool for each DM website, articles published between 2009 and 2014 which included the terms "palliative care" and "palliative medicine" were sought. A questionnaire was created to characterise each article identified and a descriptive analysis was undertaken. RESULTS: A total of 627 articles were identified, of which 359 (57%) were published in PN (42% in the printed editions -PE- 16% in their online editions -OE-) and 268 (43%) in DM. In general, they appeared mainly in sections concerning Health (23%), Culture and Society (18%) and General/Home News (15%). In PE, just 2% were found in the Health section and nearly 70% in Culture and Society and General/Home News. Most of the articles were informative in nature and contained socio-political messages (90%). Statements by PC professionals were found in 35% of the articles and by politicians in 32%. The most frequent content was related to facing end of life (74%) and patient quality of life (70%). CONCLUSIONS: The Spanish written media reflects the socio-political interest aroused by PC. Nevertheless, messages circulating about PC do not describe professional practice, or the contribution of the same for patients. Content more in line with the clinical practice might help contribute to the development of this new area of medicine

    Derivative based global sensitivity measures

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    The method of derivative based global sensitivity measures (DGSM) has recently become popular among practitioners. It has a strong link with the Morris screening method and Sobol' sensitivity indices and has several advantages over them. DGSM are very easy to implement and evaluate numerically. The computational time required for numerical evaluation of DGSM is generally much lower than that for estimation of Sobol' sensitivity indices. This paper presents a survey of recent advances in DGSM concerning lower and upper bounds on the values of Sobol' total sensitivity indices S_itotS\_{i}^{tot}. Using these bounds it is possible in most cases to get a good practical estimation of the values of S_itotS\_{i}^{tot} . Several examples are used to illustrate an application of DGSM

    Manifesto of computational social science

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    The increasing integration of technology into our lives has created unprecedented volumes of data on society's everyday behaviour. Such data opens up exciting new opportunities to work towards a quantitative understanding of our complex social systems, within the realms of a new discipline known as Computational Social Science. Against a background of financial crises, riots and international epidemics, the urgent need for a greater comprehension of the complexity of our interconnected global society and an ability to apply such insights in policy decisions is clear. This manifesto outlines the objectives of this new scientific direction, considering the challenges involved in it, and the extensive impact on science, technology and society that the success of this endeavour is likely to bring about.The publication of this work was partially supported by the European Union’s Seventh Framework Programme (FP7/2007–2013) under grant agreement No. 284709, a Coordination and Support Action in the Information and Communication Technologies activity area (‘FuturICT’ FET Flagship Pilot Project). We are grateful to the anonymous reviewers for the insightful comments.Publicad

    Effect of initial conditions on the speed of reaction-diffusion fronts

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    The effect of initial conditions on the speed of propagating fronts in reaction-diffusion equations is examined in the framework of the Hamilton-Jacobi theory. We study the transition between quenched and nonquenched fronts both analytically and numerically for parabolic and hyperbolic reaction diffusion. Nonhomogeneous media are also analyzed and the effect of algebraic initial conditions is also discussed

    Un proyecto europeo para la gestión integral de las especies vegetales invasoras en la Costa Brava

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    Póster presentado en el III Simposio Anual de Botánica Española celebrado en el Institut Botànic de Barcelona, Barcelona, 25-26 de noviembre de 2022LIFE medCLIFFS es un proyecto financiado por el programa LIFE de la Unión Europea, con una duración de cinco años y que se focaliza en la Costa Brava y en el Parque Natural de Cap de Creus, una de las zonas con acantilados litorales más afectadas en Cataluña por la problemática de las especies vegetales invasoras. Las actividades del proyecto incluyen desde acciones preventivas a acciones de erradicación y, con el mismo nivel de importancia, acciones de concienciación social y de difusión. En este sentido, involucra administraciones públicas, científicos, voluntarios y sector productivo entre sus socios, y busca la colaboración de personas individuales y entidades locales. Las acciones se centran básicamente en la detección temprana y erradicación de cinco táxones —Opuntia ficus-indica y O. stricta, Carpobrotus acinaciformis y C. edulis (y sus posibles híbridos) y Gazania rigens— lo que debería también servir para reducir su impacto en áreas sensibles que alberguen especies endémicas amenazadas como Limonium geronense, L. tremolsii y Seseli farrenyi, únicas en el mundo. En paralelo, se han creado redes participativas para la detección temprana y control de la flora alóctona invasora o potencialmente invasora, integradas por observadores y voluntarios que aportan una información clave para actualizar y calibrar un sistema automático de evaluación del riesgo de invasión (RISKMAPR). Además, puesto que la jardinería y el uso de plantas ornamentales son la principal causa del establecimiento de plantas invasoras, están previstas también las siguientes acciones específicas: redacción de una guía de buenas prácticas, incluyendo una lista con las especies inocuas y la flora ornamental a evitar y creación de una etiqueta de calidad para los proveedores y grandes usuarios, como los ayuntamientos, entre otros
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