184 research outputs found

    Time, hydrologic landscape and the long‐term storage of peatland carbon in sedimentary basins

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    Peatland carbon may enter long‐term storage in sedimentary basins preserved as either coal or lignite. The time required to account for the carbon in 1 – 10 m thick coal seams must represent 105 to 106 years, an order of magnitude more than previously assumed. To understand the process by which this happens requires extrapolation of our understanding of peatland carbon accumulation over timescales that greatly exceed those of Holocene peat. We analyse the consequences of extrapolating peat growth to periods of 106 years. We deduce that that key to sustained peat growth are hydrologic landscapes that can maintain a saturated peat body above the level of clastic deposition. Contrary to current stratigraphic frameworks we conclude that the generation of accommodation space at low rates of 0.1 to 0.2 mm/yr can adequately accommodate thick peat accumulation over periods >105 yrs. However, generation of accommodation space at rates >0.5 mm/yr cannot. The low rates that permit accommodation of thick peat are typical of the rates of subsidence in specific tectonic settings, particularly foreland basins, and this has implications for our understanding of the links between terrestrial carbon burial, tectonics and the carbon cycle. The long‐term stability of extensive peatland required to form coal also requires sediment bypass, modifying basin wide sediment transport and deposition. Limits to peatland growth under very low accommodation rates must exist but the relative importance of the limiting process is not understood. Finally, we discuss the consequences of these factors for predicting the future of the peatland carbon reservoir

    Growth rate mediates hidden developmental plasticity of female yellow dung fly reproductive morphology in response to environmental stressors

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    Understanding how environmental variation influences even cryptic traits is important to clarify the roles of selection and developmental constraints in past evolutionary divergence and to predict future adaptation under environmental change. Female yellow dung flies (Scathophaga stercoraria) typically have three sperm storage compartments (3S), but occasionally four (4S). More spermathecae are thought to be a female adaptation facilitating sperm sorting after mating, but the phenotype is very rare in nature. We manipulated the flies' developmental environment by food restriction, pesticides, and hot temperatures to investigate the nature and extent of developmental plasticity of this trait, and whether spermatheca expression correlates with measures of performance and developmental stability, as would be expected if 4S expression is a developmental aberration. The spermathecal polymorphism of yellow dung fly females is heritable, but also highly developmentally plastic, varying strongly with rearing conditions. 4S expression is tightly linked to growth rate, and weakly positively correlated with fluctuating asymmetry of wings and legs, suggesting that the production of a fourth spermatheca could be a nonadaptive developmental aberration. However, spermathecal plasticity is opposite in the closely related and ecologically similar Scathophaga suilla, demonstrating that overexpression of spermathecae under developmental stress is not universal. At the same time, we found overall mortality costs as well as benefits of 4S pheno- and genotypes (also affecting male siblings), suggesting that a life history trade-off may potentially moderate 4S expression. We conclude that the release of cryptic genetic variation in spermatheca number in the face of strong environmental variation may expose hidden traits (here reproductive morphology) to natural selection (here under climate warming or food augmentation). Once exposed, hidden traits can potentially undergo rapid genetic assimilation, even in cases when trait changes are first triggered by random errors that destabilize developmental processes

    Absolute response of Fuji imaging plate detectors to picosecond-electron bunches

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    The characterization of the absolute number of electrons generated by laser wakefield acceleration often relies on absolutely calibrated FUJI imaging plates (IP), although their validity in the regime of extreme peak currents is untested. Here, we present an extensive study on the dependence of the sensitivity of BAS-SR and BAS-MS IP to picosecond electron bunches of varying charge of up to 60 pC, performed at the electron accelerator ELBE, making use of about three orders of magnitude of higher peak intensity than in prior studies. We demonstrate that the response of the IPs shows no saturation effect and that the BAS-SR IP sensitivity of 0.0081 photostimulated luminescence per electron number confirms surprisingly well data from previous works. However, the use of the identical readout system and handling procedures turned out to be crucial and, if unnoticed, may be an important error source

    Absolute response of Fuji imaging plate detectors to picosecond-electron bunches

    Get PDF
    The characterization of the absolute number of electrons generated by laser wakefield acceleration often relies on absolutely calibrated FUJI imaging plates (IP), although their validity in the regime of extreme peak currents is untested. Here, we present an extensive study on the dependence of the sensitivity of BAS-SR and BAS-MS IP to picosecond electron bunches of varying charge of up to 60 pC, performed at the electron accelerator ELBE, making use of about three orders of magnitude of higher peak intensity than in prior studies. We demonstrate that the response of the IPs shows no saturation effect and that the BAS-SR IP sensitivity of 0.0081 photostimulated luminescence per electron number confirms surprisingly well data from previous works. However, the use of the identical readout system and handling procedures turned out to be crucial and, if unnoticed, may be an important error source

    Total Cross Section of the Reaction pp \to pK^+\Lambda Close to Threshold

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    The energy dependence of the total cross section for the pp \to pK^+\Lambda reaction was measured in the threshold region covering the excess energy range up to 7MeV. Existing model calculations describe the slope of the measured cross sections well, but are too low by a factor of two to three in rate. The data were used for a precise determination of the beam momentum of the COSY-synchrotron.Comment: 11 pages, 5 figure

    COPD – eine unterschätzte Erkrankung

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    COPD - An Underestimated Disease Abstract: Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition with a complex clinical picture. The diagnosis is not easy to make because COPD can develop insidiously and remain unnoticed for a long time. Therefore, general practitioners play a central role in the early detection of the disease. Suspected COPD can be confirmed by special examinations in collaboration with pulmonologists. The new GOLD guideline defines three COPD risk groups (A-B-E) which should guide the personalized treatment concept. A short- or long-acting bronchodilator (SAMA/SABA or LAMA/LABA) is recommended for group A, and a dual long-acting bronchodilator therapy (LABA+LAMA) is recommended for group B and E. In case of blood eosinophilia (≥300 cells/µl) and/or recent hospitalization for COPD exacerbation, triple therapy (LABA+LAMA+ICS) is recommended. General practitioners are important in implementing non-pharmacological measures (smoking cessation, regular exercise, vaccinations, patient selfmanagement education). However, this also underlines the high demands of the implementation of the GOLD guideline in daily practice.COPD ist eine heterogene Erkrankung mit komplexem Krankheitsbild. Die Diagnose ist nicht einfach zu stellen, denn COPD kann sich schleichend entwickeln und lange unbemerkt bleiben. Hausärztinnen und -ärzten kommt daher für die Früherkennung eine zentrale Rolle zu. Der COPD-Verdacht kann in Zusammenarbeit mit Pneumologen durch spezielle Untersuchungen abgesichert werden als Voraussetzung für das medikamentöse Therapiekonzept. Die neue GOLD-Guideline definiert drei COPD-Risikogruppen (A-B-E). Für Gruppe A wird ein kurz- oder langwirksamer Bronchodilatator (SAMA/SABA bzw. LAMA/LABA) empfohlen. Für Gruppe B und E wird eine Kombinationstherapie LABA+LAMA empfohlen. Bei Bluteosinophilie (≥ 300 Zellen/μl) und/oder kürzlicher Hospitalisierung aufgrund einer COPD-Exazerbation wird eine Dreifachtherapie (LABA+LAMA+ICS) empfohlen. Hausärztinnen und -ärzte sind wichtig bei der Umsetzung therapiebegleitender Massnahmen (Coaching von Patientinnen und Patienten, Impfungen, Rauchstopp, regelmässige Bewegung). Dies unterstreicht aber auch die hohen Anforderungen der Umsetzung der GOLD-Guideline in den Praxisalltag

    Absolute charge calibration of scintillating screens for relativistic electron detection

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    We report on new charge calibrations and linearity tests with high-dynamic range for eight different scintillating screens typically used for the detection of relativistic electrons from laser-plasma based acceleration schemes. The absolute charge calibration was done with picosecond electron bunches at the ELBE linear accelerator in Dresden. The lower detection limit in our setup for the most sensitive scintillating screen (KODAK Biomax MS) was 10 fC/ mm 2. The screens showed a linear photon-to-charge dependency over several orders of magnitude. An onset of saturation effects starting around 10-100 pC/ mm2 was found for some of the screens. Additionally, a constant light source was employed as a luminosity reference to simplify the transfer of a one-time absolute calibration to different experimental setups

    Long-term therapy of interferon-alpha induced pulmonary arterial hypertension with different PDE-5 inhibitors: a case report

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    BACKGROUND: Interferon alpha2 is widely used in hepatitis and high-risk melanoma. Interferon-induced pulmonary arterial hypertension as a side effect is rare. CASE PRESENTATION: We describe a melanoma patient who developed severe pulmonary arterial hypertension 30 months after initiation of adjuvant interferon alpha2b therapy. Discontinuation of interferon did not improve pulmonary arterial hypertension. This patient could be treated successfully with phosphodiesterase-5 inhibitor therapy. CONCLUSION: This is only the 5th case of interferon-induced pulmonary arterial hypertension and the first documented case where pulmonary arterial hypertension was not reversible after termination of interferon alpha2 therapy. If interferon alpha2 treated patients develop respiratory symptoms, pulmonary arterial hypertension should be considered in the differential diagnosis. For these patients phosphodiesterase-5 inhibitors, e.g. sildenafil or vardenafil, could be an effective therapeutic approach

    η\eta^{\prime} production in proton-proton scattering close to threshold}

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    The ppppηpp \to pp \eta^{\prime} (958) reaction has been measured at COSY using the internal beam and the COSY-11 facility. The total cross sections at the four different excess energies \mbox{Q= 1.5 MeV, 1.7 MeV, 2.9 MeV, Q = ~1.5 ~MeV, ~1.7 ~MeV, ~2.9 ~MeV, and  4.1MeV ~4.1 MeV} have been evaluated to be \mbox{σ=2.5±0.5 nb \sigma = 2.5 \pm 0.5~nb,    2.9±1.1 nb~~~ 2.9 \pm 1.1~nb,    12.7±3.2 nb~~~ 12.7 \pm 3.2~nb, ~ and    25.2±3.6 nb~~~ 25.2 \pm 3.6 ~nb }, respectively. In this region of excess energy the η\eta^{\prime} (958) cross sections are much lower compared to those of the π0\pi ^0 and η\eta production.Comment: 11 pages, 3 figure

    Transforming growth factor-β-inducible early response gene 1 is a novel substrate for atypical protein kinase Cs

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    The protein kinase C (PKC) family of serine/threonine kinases consists of ten different isoforms grouped into three subfamilies, denoted classical, novel and atypical PKCs (aPKCs). The aPKCs, PKCι/λ and PKCζ serve important roles during development and in processes subverted in cancer such as cell and tissue polarity, cell proliferation, differentiation and apoptosis. In an effort to identify novel interaction partners for aPKCs, we performed a yeast two-hybrid screen with the regulatory domain of PKCι/λ as bait and identified the Krüppel-like factors family protein TIEG1 as a putative interaction partner for PKCι/λ. We confirmed the interaction of both aPKCs with TIEG1 in vitro and in cells, and found that both aPKCs phosphorylate the DNA-binding domain of TIEG1 on two critical residues. Interestingly, the aPKC-mediated phosphorylation of TIEG1 affected its DNA-binding activity, subnuclear localization and transactivation potential
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