189 research outputs found

    Dissolved noble gases and stable isotopes as tracers of preferential fluid flow along faults in the Lower Rhine Embayment, Germany

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    Groundwater in shallow unconsolidated sedimentary aquifers close to the Bornheim fault in the Lower Rhine Embayment (LRE), Germany, has relatively low δ2H and δ18O values in comparison to regional modern groundwater recharge, and 4He concentrations up to 1.7 × 10−4 cm3 (STP) g–1 ± 2.2 % which is approximately four orders of magnitude higher than expected due to solubility equilibrium with the atmosphere. Groundwater age dating based on estimated in situ production and terrigenic flux of helium provides a groundwater residence time of ∼107 years. Although fluid exchange between the deep basal aquifer system and the upper aquifer layers is generally impeded by confining clay layers and lignite, this study’s geochemical data suggest, for the first time, that deep circulating fluids penetrate shallow aquifers in the locality of fault zones, implying  that sub-vertical fluid flow occurs along faults in the LRE. However, large hydraulic-head gradients observed across many faults suggest that they act as barriers to lateral groundwater flow. Therefore, the geochemical data reported here also substantiate a conduit-barrier model of fault-zone hydrogeology in unconsolidated sedimentary deposits, as well as corroborating the concept that faults in unconsolidated aquifer systems can act as loci for hydraulic connectivity between deep and shallow aquifers. The implications of fluid flow along faults in sedimentary basins worldwide are far reaching and of particular concern for carbon capture and storage (CCS) programmes, impacts of deep shale gas recovery for shallow groundwater aquifers, and nuclear waste storage sites where fault zones could act as potential leakage pathways for hazardous fluids

    Global Analysis of the Relationship between JIL-1 Kinase and Transcription

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    The ubiquitous tandem kinase JIL-1 is essential for Drosophila development. Its role in defining decondensed domains of larval polytene chromosomes is well established, but its involvement in transcription regulation has remained controversial. For a first comprehensive molecular characterisation of JIL-1, we generated a high-resolution, chromosome-wide interaction profile of the kinase in Drosophila cells and determined its role in transcription. JIL-1 binds active genes along their entire length. The presence of the kinase is not proportional to average transcription levels or polymerase density. Comparison of JIL-1 association with elongating RNA polymerase and a variety of histone modifications suggests two distinct targeting principles. A basal level of JIL-1 binding can be defined that correlates best with the methylation of histone H3 at lysine 36, a mark that is placed co-transcriptionally. The additional acetylation of H4K16 defines a second state characterised by approximately twofold elevated JIL-1 levels, which is particularly prominent on the dosage-compensated male X chromosome. Phosphorylation of the histone H3 N-terminus by JIL-1 in vitro is compatible with other tail modifications. In vivo, phosphorylation of H3 at serine 10, together with acetylation at lysine 14, creates a composite histone mark that is enriched at JIL-1 binding regions. Its depletion by RNA interference leads to a modest, but significant, decrease of transcription from the male X chromosome. Collectively, the results suggest that JIL-1 participates in a complex histone modification network that characterises active, decondensed chromatin. We hypothesise that one specific role of JIL-1 may be to reinforce, rather than to establish, the status of active chromatin through the phosphorylation of histone H3 at serine 10

    Autoregulation of the Drosophila Noncoding roX1 RNA Gene

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    Most genes along the male single X chromosome in Drosophila are hypertranscribed about two-fold relative to each of the two female X chromosomes. This is accomplished by the MSL (male-specific lethal) complex that acetylates histone H4 at lysine 16. The MSL complex contains two large noncoding RNAs, roX1 (RNA on X) and roX2, that help target chromatin modifying enzymes to the X. The roX RNAs are functionally redundant but differ in size, sequence, and transcriptional control. We wanted to find out how roX1 production is regulated. Ectopic DC can be induced in wild-type (roX1+ roX2+) females if we provide a heterologous source of MSL2. However, in the absence of roX2, we found that roX1 expression failed to come on reliably. Using an in situ hybridization probe that is specific only to endogenous roX1, we found that expression was restored if we introduced either roX2 or a truncated but functional version of roX1. This shows that pre-existing roX RNA is required to positively autoregulate roX1 expression. We also observed massive cis spreading of the MSL complex from the site of roX1 transcription at its endogenous location on the X chromosome. We propose that retention of newly assembled MSL complex around the roX gene is needed to drive sustained transcription and that spreading into flanking chromatin contributes to the X chromosome targeting specificity. Finally, we found that the gene encoding the key male-limited protein subunit, msl2, is transcribed predominantly during DNA replication. This suggests that new MSL complex is made as the chromatin template doubles. We offer a model describing how the production of roX1 and msl2, two key components of the MSL complex, are coordinated to meet the dosage compensation demands of the male cell

    The Mast Cell Degranulator Compound 48/80 Directly Activates Neurons

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    Background Compound 48/80 is widely used in animal and tissue models as a “selective” mast cell activator. With this study we demonstrate that compound 48/80 also directly activates enteric neurons and visceral afferents. Methodology/Principal Findings We used in vivo recordings from extrinsic intestinal afferents together with Ca++ imaging from primary cultures of DRG and nodose neurons. Enteric neuronal activation was examined by Ca++ and voltage sensitive dye imaging in isolated gut preparations and primary cultures of enteric neurons. Intraluminal application of compound 48/80 evoked marked afferent firing which desensitized on subsequent administration. In egg albumen-sensitized animals, intraluminal antigen evoked a similar pattern of afferent activation which also desensitized on subsequent exposure to antigen. In cross-desensitization experiments prior administration of compound 48/80 failed to influence the mast cell mediated response. Application of 1 and 10 µg/ml compound 48/80 evoked spike discharge and Ca++ transients in enteric neurons. The same nerve activating effect was observed in primary cultures of DRG and nodose ganglion cells. Enteric neuron cultures were devoid of mast cells confirmed by negative staining for c-kit or toluidine blue. In addition, in cultured enteric neurons the excitatory action of compound 48/80 was preserved in the presence of histamine H1 and H2 antagonists. The mast cell stabilizer cromolyn attenuated compound 48/80 and nicotine evoked Ca++ transients in mast cell-free enteric neuron cultures. Conclusions/Significance The results showed direct excitatory action of compound 48/80 on enteric neurons and visceral afferents. Therefore, functional changes measured in tissue or animal models may involve a mast cell independent effect of compound 48/80 and cromolyn

    Global Carbon Budget 2020

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    Accurate assessment of anthropogenic carbon dioxide (CO2_{2}) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate – the “global carbon budget” – is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2_{2} emissions (EFOS_{FOS}) are based on energy statistics and cement production data, while emissions from land-use change (ELUC_{LUC}), mainly deforestation, are based on land use and land-use change data and bookkeeping models. Atmospheric CO2_{2} concentration is measured directly and its growth rate (GATM_{ATM}) is computed from the annual changes in concentration. The ocean CO2_{2} sink (SOCEAN_{OCEAN}) and terrestrial CO2_{2} sink (SLAND_{LAND}) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM_{IM}), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the last decade available (2010–2019), EFOS_{FOS} was 9.6 ± 0.5 GtC yr1^{-1} excluding the cement carbonation sink (9.4 ± 0.5 GtC yr−1 when the cement carbonation sink is included), and ELUC_{LUC} was 1.6 ± 0.7 GtC yr1^{-1}. For the same decade, GATM_{ATM} was 5.1 ± 0.02 GtC yr1^{-1} (2.4 ± 0.01 ppm yr1_{-1}), SOCEAN_{OCEAN} 2.5 ±  0.6 GtC yr1^{-1}, and SLAND_{LAND} 3.4 ± 0.9 GtC yr1^{-1}, with a budget imbalance BIM_{IM} of −0.1 GtC yr1^{-1} indicating a near balance between estimated sources and sinks over the last decade. For the year 2019 alone, the growth in EFOS_{FOS} was only about 0.1 % with fossil emissions increasing to 9.9 ± 0.5 GtC yr1^{-1} excluding the cement carbonation sink (9.7 ± 0.5 GtC yr1^{-1} when cement carbonation sink is included), and ELUC_{LUC} was 1.8 ± 0.7 GtC yr1^{-1}, for total anthropogenic CO2_{2} emissions of 11.5 ± 0.9 GtC yr1^{-1} (42.2 ± 3.3 GtCO2_{2}). Also for 2019, GATM_{ATM} was 5.4 ± 0.2 GtC yr1^{-1} (2.5 ± 0.1 ppm yr1^{-1}), SOCEAN_{OCEAN} was 2.6 ± 0.6 GtC yr1^{-1}, and SLAND_{LAND} was 3.1 ± 1.2 GtC yr1^{-1}, with a BIM_{IM} of 0.3 GtC. The global atmospheric CO2_{2} concentration reached 409.85 ± 0.1 ppm averaged over 2019. Preliminary data for 2020, accounting for the COVID-19-induced changes in emissions, suggest a decrease in EFOS_{FOS} relative to 2019 of about −7 % (median estimate) based on individual estimates from four studies of −6 %, −7 %, −7 % (−3 % to −11 %), and −13 %. Overall, the mean and trend in the components of the global carbon budget are consistently estimated over the period 1959–2019, but discrepancies of up to 1 GtC yr1^{-1} persist for the representation of semi-decadal variability in CO2_{2} fluxes. Comparison of estimates from diverse approaches and observations shows (1) no consensus in the mean and trend in land-use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2_{2} flux in the northern extra-tropics, and (3) an apparent discrepancy between the different methods for the ocean sink outside the tropics, particularly in the Southern Ocean. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Friedlingstein et al., 2019; Le Quéré et al., 2018b, a, 2016, 2015b, a, 2014, 2013). The data presented in this work are available at https://doi.org/10.18160/gcp-2020 (Friedlingstein et al., 2020)

    Global carbon budget 2019

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    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere-the "global carbon budget"-is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (EFF) are based on energy statistics and cement production data, while emissions from land use change (ELUC), mainly deforestation, are based on land use and land use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly and its growth rate (GATM) is computed from the annual changes in concentration. The ocean CO2 sink (SOCEAN) and terrestrial CO2 sink (SLAND) are estimated with global process models constrained by observations. The resulting carbon budget imbalance (BIM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and understanding of the contemporary carbon cycle. All uncertainties are reported as ±1σ. For the last decade available (2009-2018), EFF was 9:5±0:5 GtC yr-1, ELUC 1:5±0:7 GtC yr-1, GATM 4:9±0:02 GtC yr-1 (2:3±0:01 ppm yr-1), SOCEAN 2:5±0:6 GtC yr-1, and SLAND 3:2±0:6 GtC yr-1, with a budget imbalance BIM of 0.4 GtC yr-1 indicating overestimated emissions and/or underestimated sinks. For the year 2018 alone, the growth in EFF was about 2.1% and fossil emissions increased to 10:0±0:5 GtC yr-1, reaching 10 GtC yr-1 for the first time in history, ELUC was 1:5±0:7 GtC yr-1, for total anthropogenic CO2 emissions of 11:5±0:9 GtC yr-1 (42:5±3:3 GtCO2). Also for 2018, GATM was 5:1±0:2 GtC yr-1 (2:4±0:1 ppm yr-1), SOCEAN was 2:6±0:6 GtC yr-1, and SLAND was 3:5±0:7 GtC yr-1, with a BIM of 0.3 GtC. The global atmospheric CO2 concentration reached 407:38±0:1 ppm averaged over 2018. For 2019, preliminary data for the first 6-10 months indicate a reduced growth in EFF of C0:6% (range of.0:2% to 1.5 %) based on national emissions projections for China, the USA, the EU, and India and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. Overall, the mean and trend in the five components of the global carbon budget are consistently estimated over the period 1959-2018, but discrepancies of up to 1 GtC yr-1 persist for the representation of semi-decadal variability in CO2 fluxes. A detailed comparison among individual estimates and the introduction of a broad range of observations shows (1) no consensus in the mean and trend in land use change emissions over the last decade, (2) a persistent low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) an apparent underestimation of the CO2 variability by ocean models outside the tropics. This living data update documents changes in the methods and data sets used in this new global carbon budget and the progress in understanding of the global carbon cycle compared with previous publications of this data set (Le Quéré et al., 2018a, b, 2016, 2015a, b, 2014, 2013). The data generated by this work are available at https://doi.org/10.18160/gcp-2019 (Friedlingstein et al., 2019). © 2019 by the authors

    People and Things on the Move: Domestic Material Culture, Poverty and Mobility in Victorian London

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    © 2016, The Author(s). The development of what Mayne and Lawrence (Urban History 26: 325–48, 1999) termed “ethnographic” approaches to studying nineteenth-century households and urban communities has gathered momentum in recent years. As such research agendas have taken hold and been applied to new contexts, so critiques, methodological developments, and new intellectual and theoretical currents, have provided opportunities to enhance and develop approaches. This article contributes to this on-going process. Drawing upon household archaeological research on Limehouse, a poor neighborhood in Victorian London, and inspired by the theoretical insights provided by the “new mobilities paradigm,” it aims to place “mobility” as a central and enabling intellectual framework for understanding the relationships between people, place, and poverty. Poor communities in nineteenth-century cities were undeniably mobile and transient. Historians and archaeologists have often regarded this mobility as an obstacle to studying everyday life in such contexts. However, examining temporal routines and geographical movements across a variety of time frames and geographical scales, this article argues that mobility is actually key to understanding urban life and an important mechanism for interpreting the fragmented material and documentary traces left by poor households in the nineteenth-century metropolis.We are grateful to the UK’s Arts and Humanities Research Council who funded the research upon which this paper is based (Grant Reference AH/E002285/1): ‘Living in Victorian London: Towards a Material History of Everyday Domestic Life in the Nineteenth-Century Metropolis
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