171 research outputs found

    Evaluation of modelling approaches for predicting the spatial distribution of soil organic carbon stocks at the national scale

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    Soil organic carbon (SOC) plays a major role in the global carbon budget. It can act as a source or a sink of atmospheric carbon, thereby possibly influencing the course of climate change. Improving the tools that model the spatial distributions of SOC stocks at national scales is a priority, both for monitoring changes in SOC and as an input for global carbon cycles studies. In this paper, we compare and evaluate two recent and promising modelling approaches. First, we considered several increasingly complex boosted regression trees (BRT), a convenient and efficient multiple regression model from the statistical learning field. Further, we considered a robust geostatistical approach coupled to the BRT models. Testing the different approaches was performed on the dataset from the French Soil Monitoring Network, with a consistent cross-validation procedure. We showed that when a limited number of predictors were included in the BRT model, the standalone BRT predictions were significantly improved by robust geostatistical modelling of the residuals. However, when data for several SOC drivers were included, the standalone BRT model predictions were not significantly improved by geostatistical modelling. Therefore, in this latter situation, the BRT predictions might be considered adequate without the need for geostatistical modelling, provided that i) care is exercised in model fitting and validating, and ii) the dataset does not allow for modelling of local spatial autocorrelations, as is the case for many national systematic sampling schemes

    Cellobiose Dehydrogenase Aryl Diazonium Modified Single Walled Carbon Nanotubes: Enhanced Direct Electron Transfer through a Positively Charged Surface

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    One of the challenges in the field of biosensors and biofuel cells is to establish a highly efficient electron transfer rate between the active site of redox enzymes and electrodes to fully access the catalytic potential of the biocatalyst and achieve high current densities. We report on very efficient direct electron transfer (DET) between cellobiose dehydrogenase (CDH) from Phanerochaete sordida (PsCDH) and surface modified single walled carbon nanotubes (SWCNT). Sonicated SWCNTs were adsorbed on the top of glassy carbon electrodes and modified with aryl diazonium salts generated in situ from p-aminobenzoic acid and p-phenylenediamine, thus featuring at acidic pH (3.5 and 4.5) negative or positive surface charges. After adsorption of PsCDH, both electrode types showed excellent long-term stability and very efficient DET. The modified electrode presenting p-aminophenyl groups produced a DET current density of 500,mu A cm(-2) at 200 mV vs normal hydrogen reference electrode (NHE) in a 5 mM lactose solution buffered at pH 3.5. This is the highest reported DET value so far using a CDH modified electrode and comes close to electrodes using mediated electron transfer. Moreover, the onset of the electrocatalytic current for lactose oxidation started at 70 mV vs NHE, a potential which is 50 mV lower compared to when unmodified SWCNTs were used. This effect potentially reduces the interference by oxidizable matrix components in biosensors and increases the open circuit potential in biofuel cells. The stability of the electrode was greatly increased compared with unmodified but cross-linked SWCNTs electrodes and lost only 15% of the initial current after 50 h of constant potential scanning

    Ribosomal protein gene RPL9 variants can differentially impair ribosome function and cellular metabolism

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    Variants in ribosomal protein (RP) genes drive Diamond-Blackfan anemia (DBA), a bone marrow failure syndrome that can also predispose individuals to cancer. Inherited and sporadic RP gene variants are also linked to a variety of phenotypes, including malignancy, in individuals with no anemia. Here we report an individual diagnosed with DBA carrying a variant in the 5'UTR of RPL9 (uL6). Additionally, we report two individuals from a family with multiple cancer incidences carrying a RPL9 missense variant. Analysis of cells from these individuals reveals that despite the variants both driving pre-rRNA processing defects and 80S monosome reduction, the downstream effects are remarkably different. Cells carrying the 5'UTR variant stabilize TP53 and impair the growth and differentiation of erythroid cells. In contrast, ribosomes incorporating the missense variant erroneously read through UAG and UGA stop codons of mRNAs. Metabolic profiles of cells carrying the 5'UTR variant reveal an increased metabolism of amino acids and a switch from glycolysis to gluconeogenesis while those of cells carrying the missense variant reveal a depletion of nucleotide pools. These findings indicate that variants in the same RP gene can drive similar ribosome biogenesis defects yet still have markedly different downstream consequences and clinical impacts

    Unraveling biogeographical patterns and environmental drivers of soil fungal diversity at the French national scale

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    The fungal kingdom is among the most diversified kingdoms on Earth, with estimations of up to 12 million species. However, it remains poorly understood, with only 150 000 fungal species currently described. Given the major ecological role of fungi in ecosystem functioning, these numbers stress the importance of investigating fungal diversity description across different ecosystem types. Here, we explored the spatial distribution of the soil fungal diversity on a broad geographical scale, using the French Soil Quality Monitoring Network that covers the whole French territory (2171 soils sampled along a systematic grid). Fungal alpha diversity was assessed directly from soil DNA using a meta-barcoding approach by targeting the 18S rDNA gene. The total accumulated fungal diversity across France included 136 219 operational taxonomic units (OTUs), i.e., about 1 % of worldwide soil fungal diversity (based on a maximum diversity estimate of 12 million) for a territory representing only 0.3 % of the terrestrial surface on Earth. Based on this dataset, the first extensive map of fungal alpha diversity was drawn and showed a heterogeneous and spatially structured distribution in large biogeographical patterns of 231 km radius for richness (Hill diversity of order 0) and smaller patterns of 36 km radius for dominant fungi (Hill diversity of order 2). As related to other environmental parameters, the spatial distribution of fungal diversity (Hill numbers based on different orders of diversity) was mainly influenced by local filters such as soil characteristics and land management and also by global filters such as climate conditions with various relative influences. Interestingly, cropped soils exhibited the highest pool of fungal diversity relative to forest and vineyard soils. To complement this, soil fungal OTU network interactions were calculated for the different land uses across France. They varied hugely and showed a loss of 75 % of the complexity in crop systems and grasslands compared to forests and up to 83 % in vineyard systems. Overall, our study revealed that a nationwide survey with a high spatial-resolution approach is relevant for deeply investigating the spatial distribution and determinism of soil fungal diversity. Our findings provide novel insights for a better understanding of soil fungal ecology across the 18S rDNA gene and upgrade biodiversity conservation policies by supplying representative repositories dedicated to soil fungi.</p

    The management of acute venous thromboembolism in clinical practice. Results from the European PREFER in VTE Registry

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    Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in Europe. Data from real-world registries are necessary, as clinical trials do not represent the full spectrum of VTE patients seen in clinical practice. We aimed to document the epidemiology, management and outcomes of VTE using data from a large, observational database. PREFER in VTE was an international, non-interventional disease registry conducted between January 2013 and July 2015 in primary and secondary care across seven European countries. Consecutive patients with acute VTE were documented and followed up over 12 months. PREFER in VTE included 3,455 patients with a mean age of 60.8 ± 17.0 years. Overall, 53.0 % were male. The majority of patients were assessed in the hospital setting as inpatients or outpatients (78.5 %). The diagnosis was deep-vein thrombosis (DVT) in 59.5 % and pulmonary embolism (PE) in 40.5 %. The most common comorbidities were the various types of cardiovascular disease (excluding hypertension; 45.5 %), hypertension (42.3 %) and dyslipidaemia (21.1 %). Following the index VTE, a large proportion of patients received initial therapy with heparin (73.2 %), almost half received a vitamin K antagonist (48.7 %) and nearly a quarter received a DOAC (24.5 %). Almost a quarter of all presentations were for recurrent VTE, with &gt;80 % of previous episodes having occurred more than 12 months prior to baseline. In conclusion, PREFER in VTE has provided contemporary insights into VTE patients and their real-world management, including their baseline characteristics, risk factors, disease history, symptoms and signs, initial therapy and outcomes

    Imitation and the Developing Social Brain: Infants’ Somatotopic EEG Patterns for Acts of Self and Other

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    A leading question in developmental social-cognitive neuroscience concerns the nature and function of neural links between action perception and production in early human development. Here we document a somatotopic pattern of activity of the sensorimotor EEG mu rhythm in 14-month-old infants. EEG was recorded during interactive trials in which infants activated a novel object using their own hands or feet (“execution” trials) and watched an experimenter use her hands or feet to achieve the same goal (“observation” trials). At central electrodes overlying sensorimotor hand areas (C3/C4), mu rhythm power was reduced (indicating greater cortical activation) during infants’ execution of hand acts compared to foot acts. For the central electrode overlying the sensorimotor foot area (Cz), mu power was reduced during the execution of foot versus hand acts. Strikingly similar somatotopic patterns were found in both the action execution and observation conditions. We hypothesize that these somatotopic patterns index an intercorporeal mapping of corresponding body parts between self and other. We further propose that infants’ ability to identify self-other equivalences at the level of body parts underlies infant imitation and is an ontogenetic building block for the feelings of intersubjectivity we experience when socially engaged with other people.Un asunto importante en neurociencia social-cognitiva del desarrollo tiene relación con la naturaleza y la función de los enlaces neuronales entre la percepción de la acción y la producción de la misma en el desarrollo temprano del ser humano. Aquí documentamos un patrón somatotópico de la actividad de la EEG del Ritmo Mu sensorimotor en bebés de 14 meses de edad. La EEG fue registrada durante ensayos interactivos en los cuales los bebés activaron un objeto nuevo utilizando sus propias manos o pies (ensayos de "ejecución") y vieron a un experimentador usar sus manos o pies para lograr el mismo objetivo (ensayos de "observación"). En los electrodos centrales que cubren las áreas sensoriomotoras correspondientes a la mano (C3/C4), el poder del Ritmo Mu se redujo (indicando una mayor activación cortical) durante la ejecución por los bebés de actos de la mano en comparación con actos del pie. Para los electrodos centrales que cubren el área sensoriomotora correspondiente al pie (Cz), el poder Mu se redujo durante la ejecución de actos del pie versus actos de la mano. Sorprendetemente, patrones somatotópicos similares fueron encontrados tanto en la ejecución como en la observación de la acción. Tenemos la hipótesis de que estos patrones somatotópicos indican un mapeado intracorpóreo de las partes del cuerpo correspondientes entre uno mismo y los otros. Además, proponemos que la capacidad de los bebés para identificar equivalencias respecto a las partes del cuerpo entre ellos mismos y el otro es la base de la imitación infantil y es un bloque de construcción ontogenético para los sentimientos de intersubjetividad que experimentamos cuando nos comprometemos socialmente con otras personas
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