46 research outputs found

    Magnetic induction responses of Jupiter's ocean moons including effects from adiabatic convection

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    Prior analyses of oceanic magnetic induction within Jupiter's large icy moons have assumed uniform electrical conductivity. However, the phase and amplitude responses of the induced fields will be influenced by the natural depth‐dependence of the electrical conductivity. Here, we examine the amplitudes and phase delays for magnetic diffusion in modeled oceans of Europa, Ganymede, and Callisto. For spherically symmetric configurations, we consider thermodynamically consistent interior structures that include realistic electrical conductivity along the oceans' adiabatic temperature profiles. Conductances depend strongly on salinity, especially in the large moons. The induction responses of the adiabatic profiles differ from those of oceans with uniform conductivity set to values at the ice–ocean interface, or to the mean values of the adiabatic profile, by more than 10% for some signals. We also consider motionally induced magnetic fields generated by convective fluid motions within the oceans, which might optimistically be used to infer ocean flows or, pessimistically, act to bias the ocean conductivity inversions. Our upper‐bound scaling estimates suggest this effect may be important at Europa and Ganymede, with a negligible contribution at Callisto. Based on end‐member ocean compositions, we quantify the magnetic induction signals that might be used to infer the oxidation state of Europa's ocean and to investigate stable liquids under high‐pressure ices in Ganymede and Callisto. Fully exploring this parameter space for the sake of planned missions requires thermodynamic and electrical conductivity measurements in fluids at low temperature and to high‐salinity and pressure as well as modeling of motional induction responses

    A systems biology approach uncovers cell-specific gene regulatory effects of genetic associations in multiple sclerosis.

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    Genome-wide association studies (GWAS) have identified more than 50,000 unique associations with common human traits. While this represents a substantial step forward, establishing the biology underlying these associations has proven extremely difficult. Even determining which cell types and which particular gene(s) are relevant continues to be a challenge. Here, we conduct a cell-specific pathway analysis of the latest GWAS in multiple sclerosis (MS), which had analyzed a total of 47,351 cases and 68,284 healthy controls and found more than 200 non-MHC genome-wide associations. Our analysis identifies pan immune cell as well as cell-specific susceptibility genes in T cells, B cells and monocytes. Finally, genotype-level data from 2,370 patients and 412 controls is used to compute intra-individual and cell-specific susceptibility pathways that offer a biological interpretation of the individual genetic risk to MS. This approach could be adopted in any other complex trait for which genome-wide data is available

    A systems biology approach uncovers cell-specific gene regulatory effects of genetic associations in multiple sclerosis

    Get PDF
    Genome-wide association studies (GWAS) have identified more than 50,000 unique associations with common human traits. While this represents a substantial step forward, establishing the biology underlying these associations has proven extremely difficult. Even determining which cell types and which particular gene(s) are relevant continues to be a challenge. Here, we conduct a cell-specific pathway analysis of the latest GWAS in multiple sclerosis (MS), which had analyzed a total of 47,351 cases and 68,284 healthy controls and found more than 200 non-MHC genome-wide associations. Our analysis identifies pan immune cell as well as cell-specific susceptibility genes in T cells, B cells and monocytes. Finally, genotype-level data from 2,370 patients and 412 controls is used to compute intra-individual and cell-specific susceptibility pathways that offer a biological interpretation of the individual genetic risk to MS. This approach could be adopted in any other complex trait for which genome-wide data is available

    Oxygen production from dissociation of Europa’s water-ice surface

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    Jupiter’s moon Europa has a predominantly water-ice surface that is modified by exposure to its space environment. Charged particles break molecular bonds in surface ice, thus dissociating the water to ultimately produce H2 and O2, which provides a potential oxygenation mechanism for Europa’s subsurface ocean. These species are understood to form Europa’s primary atmospheric constituents. Although remote observations provide important global constraints on Europa’s atmosphere, the molecular O2 abundance has been inferred from atomic O emissions. Europa’s atmospheric composition had never been directly sampled and model-derived oxygen production estimates ranged over several orders of magnitude. Here, we report direct observations of H2+ and O2+ pickup ions from the dissociation of Europa’s water-ice surface and confirm these species are primary atmospheric constituents. In contrast to expectations, we find the H2 neutral atmosphere is dominated by a non-thermal, escaping population. We find 12 ± 6 kg s−1 (2.2 ± 1.2 × 1026 s−1) O2 are produced within Europa’s surface, less than previously thought, with a narrower range to support habitability in Europa’s ocean. This process is found to be Europa’s dominant exogenic surface erosion mechanism over meteoroid bombardment

    Ice-Ocean Exchange Processes in the Jovian and Saturnian Satellites

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    Lodo de esgoto em atributos biológicos do solo e na nodulação e produção de soja Sewage sludge effects on soil biological parameters and on soybean nodulation and yield

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    O objetivo deste trabalho foi avaliar os efeitos da aplicação do lodo produzido pela Companhia de Saneamento Ambiental do Distrito Federal (Caesb) na nodulação e rendimento de grãos da soja e em atributos biológicos de um Latossolo Vermelho de Cerrado. O experimento foi conduzido por dois anos consecutivos em um delineamento experimental de blocos ao acaso com três repetições e nove tratamentos - um controle, quatro doses de lodo de esgoto e quatro doses de fertilizante mineral - aplicados apenas no primeiro ano de cultivo. Foram avaliados: a nodulação e a produtividade da soja, o carbono da biomassa microbiana, o carbono prontamente mineralizável e a atividade das enzimas beta-glicosidase, fosfatase ácida e arilsulfatase no solo. Nos dois anos agrícolas, o rendimento de grãos da soja foi inferior ao do tratamento com o fertilizante mineral somente na dose de 1,5 Mg ha-1 de lodo de esgoto. A aplicação do lodo de esgoto no primeiro ano de cultivo não afetou a nodulação da soja, e a aplicação de até 6 Mg ha-1 não apresentou efeito sobre o carbono da biomassa microbiana, o carbono prontamente mineralizável e a atividade das enzimas beta-glicosidase, arilsulfatase e fosfatase ácida do solo no período de dois anos.<br>The objective of this study was to evaluate the effects of applying sewage sludge produced by the Companhia de Saneamento Ambiental do Distrito Federal (Caesb) on the nodulation and yield of soybean and on the biological parameters of a Cerrado Oxisol. The experiment was done for two consecutive years in a completely randomized block design with three replicates and nine treatments - one control, four dosages of sewage sludge and four dosages of mineral fertilizer - applied only in the first year of the experiment. Soybean nodulation, grain yield, soil microbial biomass carbon, readily mineralizable carbon and activity of the beta-glucosidase, acid phosphatase and arylsulphatase enzymes were evaluated. In both years, the grain yield was lower than that of the mineral fertilizer only at the sewage sludge dose of 1.5 Mg ha-1. The application of sewage sludge in the first year of the crop does not affect soybean nodulation, and the application of up to 6 Mg ha-1 of sewage sludge had no effect on microbial biomass carbon, readily mineralizable carbon and on the activity of the beta-glucosidase, arylsulphatase and acid phosphatase soil enzymes in the two-year period
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