62 research outputs found

    Early diagenesis of trace metals (V, Mo, U) in sediments of the Peruvian upwelling area: response to oxygen dynamics in the water column

    Get PDF
    The upwelling area in the eastern equatorial Pacific off Peru is one of the most pronounced oxygen minimum zones (OMZs) of the modern ocean. Modeling scenarios predict an expansion of the OMZs in the course of global change in the coming decades. As a consequence, the Peruvian continental margin represents a key locality for studies on biogeochemical dynamics in the future ocean. We present pore water and sediment data for redox-sensitive metals (Fe, Mn, V, Mo, and U) that have been collected along a transect across the Peruvian margin at 11°S. The results are used to evaluate the behavior of trace metals in a wide range of biogeochemical and hydrodynamic settings. In the core of the OMZ, where permanently anoxic conditions prevail, redox sensitive metals exhibit diagenetic behaviors largely consistent with previous studies. Vanadium and Mo are released from Fe oxihydroxides and subsequently recycled through diffusion across the benthic boundary or trapped through formation of authigenic V phases and sequestration of Mo by authigenic pyrite. Some U is delivered through diffusion across the benthic boundary, reduction and precipitation of UO2 and incorporation into phosphorites. The utmost part of the buried U, however, is delivered in particulate form, most likely as bioauthigenic U which cannot be recycled in the suboxic waters overlying the anoxic sediments. In contrast to sediments in the core of the OMZ, sediments on the shelf experience frequent oxygenation episodes related to the passage of internal waves and the regular recurrence of El Niño events. These oxygenation episodes lead to the re-oxidation and remobilization of authigenic U and V. In contrast to that, the authigenic accumulation of Mo is favored by the occasional occurrence of slightly oxidizing conditions. This is most likely due to enhanced formation of sulfur intermediates necessary for pyrite formation and the increased stability of pyrite, the major Mo sink, under oxidizing conditions, compared to authigenic V and U phases. Redox oscillations in the Peruvian OMZ thus lead to a discrimination of U against Mo, a mechanism that should be considered in the interpretation of U/Mo systematics in paleo redox studies. Overall our results provide valuable constraints on how trace metal inventories of marginal sediments may respond to expanding shelf anoxia and to short term perturbations of sediment redox conditions

    Survival Benefit for Individuals With Constitutional Mismatch Repair Deficiency Undergoing Surveillance

    Get PDF
    PURPOSE: Constitutional mismatch repair deficiency syndrome (CMMRD) is a lethal cancer predisposition syndrome characterized by early-onset synchronous and metachronous multiorgan tumors. We designed a surveillance protocol for early tumor detection in these individuals. PATIENTS AND METHODS: Data were collected from patients with confirmed CMMRD who were registered in the International Replication Repair Deficiency Consortium. Tumor spectrum, efficacy of the surveillance protocol, and malignant transformation of low-grade lesions were examined for the entire cohort. Survival outcomes were analyzed for patients followed prospectively from the time of surveillance implementation. RESULTS: A total of 193 malignant tumors in 110 patients were identified. Median age of first cancer diagnosis was 9.2 years (range: 1.7-39.5 years). For patients undergoing surveillance, all GI and other solid tumors, and 75% of brain cancers were detected asymptomatically. By contrast, only 16% of hematologic malignancies were detected asymptomatically (P \u3c .001). Eighty-nine patients were followed prospectively and used for survival analysis. Five-year overall survival (OS) was 90% (95% CI, 78.6 to 100) and 50% (95% CI, 39.2 to 63.7) when cancer was detected asymptomatically and symptomatically, respectively (P = .001). Patient outcome measured by adherence to the surveillance protocol revealed 4-year OS of 79% (95% CI, 54.8 to 90.9) for patients undergoing full surveillance, 55% (95% CI, 28.5 to 74.5) for partial surveillance, and 15% (95% CI, 5.2 to 28.8) for those not under surveillance (P \u3c .0001). Of the 64 low-grade tumors detected, the cumulative likelihood of transformation from low-to high-grade was 81% for GI cancers within 8 years and 100% for gliomas in 6 years. CONCLUSION: Surveillance and early cancer detection are associated with improved OS for individuals with CMMRD

    MAGIC and H.E.S.S. detect VHE gamma rays from the blazar OT081 for the first time: a deep multiwavelength study

    Get PDF
    https://pos.sissa.it/395/815/pdfPublished versio

    Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

    Get PDF
    Abstract: In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M ⊙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded

    ifo Migrationsmonitor: Fakten zur Kriminalität von Geflüchteten

    Full text link
    Wer nur die Anteile der Geflüchteten in der Kriminalstatistik betrachtet, lässt wichtige Faktoren außer Acht: etwa das Anzeigeverhalten gegenüber Geflüchteten oder deren Alters- und Geschlechtsstruktur. Es fehlt außerdem an Medienaufmerksamkeit für die spezifischen, tiefer liegenden Gründe der Kriminalität unter Geflüchteten. Dabei könnte es sich um die Lebensbedingungen in den Unterkünften oder auch die Orientierungs- und Perspektiven­losigkeit in Deutschland handeln. Neben Verzerrungs- und möglichen Einflussfaktoren stellt der Artikel präventive Maßnahmen vor, um die Gewaltbereitschaft zu reduzieren

    Sea ice drift from autonomous measurements from buoy 2019P92, deployed during MOSAiC 2019/20

    No full text
    Sea ice drift was measured by Surface Velocity Profiler 2019P92, an autonomous platform, installed on drifting sea ice in the Arctic Ocean during MOSAiC (Leg 1) 2019/20. The time series describes the position and additional parameters of the buoy between 05 Oct 2019 and 13 August 2020 in sample intervals of 10 minutes. The data set has been processed, including the flagging of obvious inconsistencies in position. The position is flagged if the drift velocity exceeds a threshold (Quality flag, position = 1), if the position exceeds extreme values, such as longitutde > 360 deg (Quality flag, position = 2), and if the position is exactly 0.0 (Quality flag, position = 4). These quality flag values can be sums of each other

    Sea ice drift from autonomous measurements from buoy 2019P91, deployed during MOSAiC 2019/20

    No full text
    Sea ice drift was measured by Surface Velocity Profiler 2019P91, an autonomous platform, installed on drifting sea ice in the Arctic Ocean during MOSAiC (Leg 1) 2019/20. The time series describes the position and additional parameters of the buoy between 07 Oct 2019 and 15 April 2020 in sample intervals of 10 minutes. The data set has been processed, including the flagging of obvious inconsistencies in position. The position is flagged if the drift velocity exceeds a threshold (Quality flag, position = 1), if the position exceeds extreme values, such as longitutde > 360 deg (Quality flag, position = 2), and if the position is exactly 0.0 (Quality flag, position = 4). These quality flag values can be sums of each other
    corecore