Global 3-D electromagnetic forward modelling: a benchmark study

Global electromagnetic (EM) induction studies have been the focus of increasing attention during the past few years. A primary stimulus for this interest has been increased quality, coverage and variety of the newly available data sets especially from recent low-Earth-orbiting satellite missions. The combination of traditional ground-based data with satellite-borne measurements presents intriguing opportunity to attack the most challenging problem of deep EM studies: the recovery of 3-D variations of electrical conductivity in the Earth's mantle. But the reliable inference of deep-Earth electrical properties depends on the accuracy and efficiency of the underlying forward modelling solutions used to model 3-D electromagnetic induction in a heterogeneous sphere. Several 3-D forward solvers have been proposed over the last decade, which are based on staggered-grid finite difference, integral equation, finite element and spherical harmonic-finite element approaches. However, there has been no systematic intercomparison amongst the solvers. The goal of this paper is to conduct such a study in order to explore the relative merits of the different approaches when confronted with a set of synthetic models designed to probe the numerical accuracy of each. The results of the intercomparison are presented along with performance metrics to help assess the computational costs associated with each solutio

Global 3-D electromagnetic forward modelling: a benchmark study

Global electromagnetic (EM) induction studies have been the focus of increasing attention during the past few years. A primary stimulus for this interest has been increased quality, coverage and variety of the newly available data sets especially from recent low-Earth-orbiting satellite missions. The combination of traditional ground-based data with satellite-borne measurements presents intriguing opportunity to attack the most challenging problem of deep EM studies: the recovery of 3-D variations of electrical conductivity in the Earth’s mantle. But the reliable inference of deep-Earth electrical properties depends on the accuracy and efficiency of the underlying forward modelling solutions used to model 3-D electromagnetic induction in a heterogeneous sphere. Several 3-D forward solvers have been proposed over the last decade, which are based on staggered-grid finite difference, integral equation, finite element and spherical harmonic-finite element approaches. However, there has been no systematic intercomparison amongst the solvers. The goal of this paper is to conduct such a study in order to explore the relative merits of the different approaches when confronted with a set of synthetic models designed to probe the numerical accuracy of each. The results of the intercomparison are presented along with performance metrics to help assess the computational costs associated with each solution.This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by Oxford University Press on behalf of the Royal Astronomical Society. The published article can be found at: http://gji.oxfordjournals.org/.Keywords: Numerical approximations and analysis, Non-linear electromagnetics, Geomagnetic induction, Composition of the mantle, Numerical solutionsKeywords: Numerical approximations and analysis, Non-linear electromagnetics, Geomagnetic induction, Composition of the mantle, Numerical solution

Expanded phenotypic spectrum of neurodevelopmental and neurodegenerative disorder Bryant-Li-Bhoj syndrome with 38 additional individuals

Bryant-Li-Bhoj syndrome (BLBS), which became OMIM-classified in 2022 (OMIM: 619720, 619721), is caused by germline variants in the two genes that encode histone H3.3 (H3-3A/H3F3A and H3-3B/H3F3B) [1-4]. This syndrome is characterized by developmental delay/intellectual disability, craniofacial anomalies, hyper/hypotonia, and abnormal neuroimaging [1, 5]. BLBS was initially categorized as a progressive neurodegenerative syndrome caused by de novo heterozygous variants in either H3-3A or H3-3B [1-4]. Here, we analyze the data of the 58 previously published individuals along 38 unpublished, unrelated individuals. In this larger cohort of 96 people, we identify causative missense, synonymous, and stop-loss variants. We also expand upon the phenotypic characterization by elaborating on the neurodevelopmental component of BLBS. Notably, phenotypic heterogeneity was present even amongst individuals harboring the same variant. To explore the complex phenotypic variation in this expanded cohort, the relationships between syndromic phenotypes with three variables of interest were interrogated: sex, gene containing the causative variant, and variant location in the H3.3 protein. While specific genotype-phenotype correlations have not been conclusively delineated, the results presented here suggest that the location of the variants within the H3.3 protein and the affected gene (H3-3A or H3-3B) contribute more to the severity of distinct phenotypes than sex. Since these variables do not account for all BLBS phenotypic variability, these findings suggest that additional factors may play a role in modifying the phenotypes of affected individuals. Histones are poised at the interface of genetics and epigenetics, highlighting the potential role for gene-environment interactions and the importance of future research

Calculation of element distributions between inorganic and organic parts of coal

A procedure for calculation of the quantitative element distribution between inorganic and organic parts of coal is proposed. Individual coal fractions with different contents of inorganic matter are prepared from the original coal sample and the following input data are determined for each coal fraction: (1) weight of the fraction; (2) concentration of elements for the distribution to be calculated; (3) sum of crystalline phases and the ash content. Furthermore, during the procedure the following assumptions were used: (a) non-crystalline phases in coal are neglected; (b) concentrations of elements bonded to the organic part of coal are constant and independent of the content of crystalline phases in individual coal fractions; (c) the relation between the mass of the inorganic part of coal fractions and the concentration of elements bonded on the inorganic part can be approximated by a quadratic function. Using two samples of different coals the procedure was applied for calculation of the distribution of Pb, Ge and As between inorganic and organic parts of coal

Water leaching of cesium from selected cesium mineral analogues

Recently, a new mica phase Cs-tetra-ferri-annite has been synthesized and studied. This phase has been investigated because its high structural stability and assumed associated low leachability for Cs suggest that it may be a suitable waste form for immobilization of Cs. Further, synthesis, under hydrothermal conditions, is possible under conditions typical of an industrial-scale immobilization plant. Consequently, cesium-tetra-ferri-annite can be considered as a waste form for the fixation of Cs from solid radioactive waste. In this study, Cs immobilization in Cs-tetra-ferri-annite and CsAlSiO4, as well as sorption onto montmorillonite and zeolite 13X, have been studied. Experiments were carried out to determine the influence of pH, temperature, time and leaching technique on the extent of release of Cs from these solids. These leaching studies have confirmed the limited leachability of Cs-tetra-ferri-annite, which was found to be more stable than CsAlSiO4 by a factor of 3.7 at ambient temperature and near-neutral pH. These waste forms have also been found to be more effective in retaining Cs than Cs-montmorillonite and Cs-zeolite 13X. The relative release of Cs from all of the studied phases exhibits a similar trend with pH, temperature, time and techniques of leaching used in this study. For these phases, the leachability of Cs increases with acidity (pH 3) or alkalinity (pH 11) of the leachates as well as with increasing temperature and time of leaching. For CsAlSiO4, the Cs-leachability was most strongly affected by increasing temperature. Cesium releases from this phase increased by a factor of about 6 when the temperature was raised from 20 to 100 °C. This increase with temperature was 3–6 times higher than that measured for the other phases. Under the present leaching conditions, Cs is released more than the matrix elements. Elements present in tetrahedral positions of CsAlSiO4, Cs-montmorillonite and Cs-zeolite 13X leach much easier than elements in octahedral positions