A detailed model of the Irish High Voltage Power Network for simulating GICs

Constructing a power network model for geomagnetically induced current (GIC) calculations requires information on the DC resistances of elements within a network. This information is often not known, and power network models are simplified as a result, with assumptions used for network element resistances. Ireland's relatively small, isolated network presents an opportunity to model a complete power network in detail, using as much real‐world information as possible. A complete model of the Irish 400, 275, 220, and 110 kV network was made for GIC calculations, with detailed information on the number, type, and DC resistances of transformers. The measured grounding resistances at a number of substations were also included in the model, which represents a considerable improvement on previous models of the Irish power network for GIC calculations. Sensitivity tests were performed to show how calculated GIC amplitudes are affected by different aspects of the model. These tests investigated: (1) How the orientation of a uniform electric field affects GICs. (2) The effect of including/omitting lower voltage elements of the power network. (3) How the substation grounding resistances assumptions affected GIC values. It was found that changing the grounding resistance value had a considerable effect on calculated GICs at some substations and no discernible effect at others. Finally, five recent geomagnetic storm events were simulated in the network. It was found that heavy rainfall prior to the 26–28 August 2015 geomagnetic storm event may have had a measurable impact on measured GIC amplitudes at a 400/220 kV transformer ground

Transcriptional programs regulating neuronal differentiation are disrupted in DLG2 knockout human embryonic stem cells and enriched for schizophrenia and related disorders risk variants

Coordinated programs of gene expression drive brain development. It is unclear which transcriptional programs, in which cell-types, are affected in neuropsychiatric disorders such as schizophrenia. Here we integrate human genetics with transcriptomic data from differentiation of human embryonic stem cells into cortical excitatory neurons. We identify transcriptional programs expressed during early neurogenesis in vitro and in human foetal cortex that are down-regulated in DLG2−/− lines. Down-regulation impacted neuronal differentiation and maturation, impairing migration, morphology and action potential generation. Genetic variation in these programs is associated with neuropsychiatric disorders and cognitive function, with associated variants predominantly concentrated in loss-of-function intolerant genes. Neurogenic programs also overlap schizophrenia GWAS enrichment previously identified in mature excitatory neurons, suggesting that pathways active during prenatal cortical development may also be associated with mature neuronal dysfunction. Our data from human embryonic stem cells, when combined with analysis of available foetal cortical gene expression data, de novo rare variants and GWAS statistics for neuropsychiatric disorders and cognition, reveal a convergence on transcriptional programs regulating excitatory cortical neurogenesis

Erosão hídrica pós-plantio em florestas de eucalipto na bacia do rio Paraná, no leste do Mato Grosso do Sul

Nas regiões tropicais, o desgaste provocado no solo por ação das águas da chuva, ou seja, a erosão hídrica é a mais importante forma de degradação do solo. Visto que os plantios florestais de eucalipto estão inseridos em ecossistemas sensíveis às perturbações antrópicas em razão de ocorrência de plantações em solos com baixos teores de argila, com baixa fertilidade natural e grande parte das plantações estabelecidas em antigas áreas agrícolas e de pastagens degradadas, surge a necessidade do entendimento dos processos que regem a erosão hídrica e suas relações com as perdas de solo e água nos sistemas florestais. Objetivaram-se com este trabalho calcular os valores de erosividade da chuva (fator R - EI30), estimar a tolerância de perda de solo (T) para as classes representativas nas áreas de estudo, avaliar as perdas de solo e água por erosão hídrica e verificar a influência, por meio de análise de componentes principais (ACP), de atributos físicos e matéria orgânica do solo sobre a erosão hídrica em florestas de eucalipto no estádio de pós-plantio. Os tratamentos constituíram de diferentes sistemas de manejo dos resíduos e da disposição de plantio (nível e desnível), em dois biomas distintos, Cerrado e Floresta, e solo descoberto. Os solos foram classificados como Latossolo Vermelho distrófico típico textura média-alta fase floresta (LVd1) e Latossolo Vermelho distrófico típico textura média-baixa fase cerrado (LVd2). O estudo foi realizado em áreas experimentais de plantio de eucalipto localizadas no município de Três Lagoas, na bacia do Rio Paraná, no leste do Mato Grosso do Sul. O índice de erosividade anual obtido foi de 6.792,7 MJ mm ha-1 h-1 ano-1. Os valores de T variaram de 9,0 a 11,0 Mg ha-1 ano-1, para o LVd2 e LVd1, respectivamente. As perdas de solo apresentaram valores em torno de 0 a 0,505 Mg ha-1 no LVd1 e de 0 a 0,853 Mg ha-1, no LVd2. A ACP evidenciou-se eficiente na discriminação dos sistemas de manejo em razão da interação entre os atributos físicos e matéria orgânica do solo e suas relações com a erosão hídrica, possibilitando visualizar de forma clara a influência do manejo sobre esses atributos e a relação de ambos com as perdas de solo e água

Mate choice for genetic quality: a test of the heterozygosity and compatibility hypotheses in a lek-breeding bird

Understanding female mate choice in nonresource-based mating systems, where females appear to express strong preferences despite receiving no direct benefits from mate choice, remain a challenge to behavioral ecology. Brown (Brown JL. 1997. A theory of mate choice based on heterozygosity. Behav Ecol. 8:60–65) proposed the “good-genes-as-heterozygosity” hypothesis, which sought to establish the genetic nature of male quality. Despite recent attention, few studies have examined how multiple components of genetic quality influence mate choice in a highly promiscuous mating system such as that of the lekking wire-tailed manakin (Pipra filicauda, Aves: Pipridae). Based on a 4-year study in the Amazon basin of Ecuador we ask whether female wire-tailed manakins use heterozygosity and/or dissimilarity (relatedness) as mate-choice criteria, and if heterozygosity influences the ontogeny of male social status. Our data show that females select more heterozygous males as their partners. Females do not, however, appear to select mates based on their genetic dissimilarity as mated pairs were more related than expected under random mating. Heterozygosity of territorial males was correlated with 2 male morphological traits (wing and tarsus length), which suggests that females may assess male genetic quality via phenotypic correlates. In addition, our data show that heterozygosity was related to male social rise (territory acquisition) and suggests that heterozygosity may act as a filter of male reproductive potential. Lastly, we find no support for indirect benefits (i.e., increased offspring genetic quality) obtained via female choice for heterozygous males

Synaptic protein DLG2 controls neurogenic transcriptional programs disrupted in schizophrenia and related disorders

Genetic studies robustly implicate perturbation of DLG2-scaffolded mature postsynaptic signalling complexes in schizophrenia. Here we study in vitro cortical differentiation of DLG2-/- human embryonic stem cells via integrated phenotypic, gene expression and disease genetic analyses. This uncovers a developmental role for DLG2 in the regulation of neural stem cell proliferation and adhesion, and the activation of transcriptional programs during early excitatory corticoneurogenesis. Down-regulation of these programs in DLG2-/- lines delays expression of cell-type identity and causes marked deficits in neuronal migration, morphology and active properties. Genetic risk factors for neuropsychiatric and neurodevelopmental disorders converge on these neurogenic programs, each disorder displaying a distinct pattern of enrichment. These data unveil an intimate link between neurodevelopmental and mature signalling deficits contributing to disease - suggesting a dual role for known synaptic risk genes - and reveal a common pathophysiological framework for studying the neurodevelopmental origins of Mendelian and genetically complex mental disorders