65 research outputs found

    Dynamic protein methylation in chromatin biology

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    Post-translational modification of chromatin is emerging as an increasingly important regulator of chromosomal processes. In particular, histone lysine and arginine methylation play important roles in regulating transcription, maintaining genomic integrity, and contributing to epigenetic memory. Recently, the use of new approaches to analyse histone methylation, the generation of genetic model systems, and the ability to interrogate genome wide histone modification profiles has aided in defining how histone methylation contributes to these processes. Here we focus on the recent advances in our understanding of the histone methylation system and examine how dynamic histone methylation contributes to normal cellular function in mammals

    Volume I. Introduction to DUNE

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    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from the high-level physics goals through requirements at all levels of the Project. Volume I contains an executive summary that introduces the DUNE science program, the far detector and the strategy for its modular designs, and the organization and management of the Project. The remainder of Volume I provides more detail on the science program that drives the choice of detector technologies and on the technologies themselves. It also introduces the designs for the DUNE near detector and the DUNE computing model, for which DUNE is planning design reports. Volume II of this TDR describes DUNE\u27s physics program in detail. Volume III describes the technical coordination required for the far detector design, construction, installation, and integration, and its organizational structure. Volume IV describes the single-phase far detector technology. A planned Volume V will describe the dual-phase technology

    Deep Underground Neutrino Experiment (DUNE), far detector technical design report, volume III: DUNE far detector technical coordination

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    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume III of this TDR describes how the activities required to design, construct, fabricate, install, and commission the DUNE far detector modules are organized and managed. This volume details the organizational structures that will carry out and/or oversee the planned far detector activities safely, successfully, on time, and on budget. It presents overviews of the facilities, supporting infrastructure, and detectors for context, and it outlines the project-related functions and methodologies used by the DUNE technical coordination organization, focusing on the areas of integration engineering, technical reviews, quality assurance and control, and safety oversight. Because of its more advanced stage of development, functional examples presented in this volume focus primarily on the single-phase (SP) detector module

    Redox-driven changes in porewater chemistry in the unsaturated zone of the chalk aquifer beneath unlined cattle slurry lagoons

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    Farm waste stores such as cattle slurry lagoons are widespread in the UK and many overly important aquifers. Stores can be serious risks to water quality because they are important sources of N species, organic C and pathogenic microbes. At two sites on the Chalk aquifer of southern England, inclined boreholes were drilled and cored to obtain aquifer material from directly beneath unlined slurry stores. Vertical boreholes were also drilled adjacent to the slurry stores to determine any lateral movement of contaminants. Interstitial porewaters were analysed for major and minor ions and S isotopes. At the second site, unsaturated zone gases were sampled from the inclined hole. Infiltration of slurry into the unsaturated zone caused significantly elevated concentrations of metals such as Cu and Ni at both sites. Sulphate reduction was occurring at Site 1, as evidenced by SO4 concentrations decreasing from 150 to 50 mg/l and enhanced ratios of delta(34)S-SO4 and delta(18)O-SO4. Ammomum-N also leaches along with dissolved organic C which were found 17 m below ground surface at concentrations up to 400 and 260 mg/l, respectively. Contaminant concentrations were similar in the porewaters from both the inclined and vertical boreholes. At Site 2, higher contaminant concentrations were found in the inclined borehole compared with the vertical borehole. Organic C concentrations were considerably lower than at Site 1, ranging from 10 to 70 mg/l. Ammonium-N concentrations reached a maximum concentration of 25 mg/l. however NO3-N concentrations were up to 500 mg/l and SO4 concentrations were generally higher than Site 1. Data for N-2/Ar and delta(15)N-N-2 from the gas samplers show a peak of 102 and 2.2parts per thousand, respectively. at 14 m below ground level indicating denitrification was taking place. Evidence from delta(34)S- SO4 and delta(18)O-SO4 suggest that some SO4 reduction was taking place simultaneously. From CH4 and NH3 detected at depth it is suggested that slurry contamination. emanating from early use of the store, has passed through the top 18 m of the unsaturated zone at Site 2. The presence of high concentrations of NO3 and lower concentrations of organic C suggests that this lagoon has formed a relatively impermeable seal at its base within the first few years of its lifetime. The anoxic conditions at both sites may have mobilised U from N-P-K fertilisers. Both sites are continuing to impact on the porewater chemistry and pose a risk of groundwater contamination

    Dynamics of the evolution of Batesian mimicry: molecular phylogenetic analysis of ant-mimicking Myrmarachne (Araneae: Salticidae) species and their ant models

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    Batesian mimicry is seen as an example of evolution by natural selection, with predation as the main driving force. The mimic is under selective pressure to resemble its model, whereas it is disadvantageous for the model to be associated with the palatable mimic. In consequence one might expect there to be an evolutionary arms race, similar to the one involving host–parasite coevolution. In this study, the evolutionary dynamics of a Batesian mimicry system of model ants and ant-mimicking salticids is investigated by comparing the phylogenies of the two groups. Although Batesian mimics are expected to coevolve with their models, we found the phylogenetic patterns of the models and the mimics to be indicative of adaptive radiation by the mimic rather than co-speciation between the mimic and the model. This shows that there is strong selection pressure on Myrmarachne, leading to a high degree of polymorphism. There is also evidence of sympatric speciation in Myrmarachne, the reproductive isolation possibly driven by female mate choice in polymorphic species

    Anchored phylogenomics of burrowing mayflies (Ephemeroptera) and the evolution of tusks : Phylogeny of burrowing mayflies

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    This study investigated the phylogenetic relationships among seven burrowing mayfly families. Genetic data from four ribosomal DNA genes (12S, 16S, 18S and 28S) generated with Sanger sequencing, 448 protein-coding loci generated using a novel hybrid enrichment probe set and available RNAseq and genome assembly for 19 ingroup taxa and four outgroup taxa. Maximum likelihood and Bayesian analyses were carried out to estimate phylogenetic relationships. The results indicated that Potamanthidae, Euthyplociidae, Behningiidae and Palingeniidae were recovered as monophyletic. Ephemeridae was not monophyletic. Mandibular tusks evolved in the common ancestor of burrowing mayflies and were lost in the lineage leading to Behningiidae
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