Short length-scale variability of hybrid event beds and its applied significance

Hybrid event beds (HEBs) are a type of deep-water sediment gravity flow deposit that generally comprise a basal clean sandstone overlain by a variety of muddier and less-permeable sandy facies. They are thought to be emplaced by combinations of turbidity currents, transitional flows and debris flows, all as part of the same transport event. To date, a number of studies have highlighted the common presence of HEBs mainly in the outer and marginal parts of deep-water systems where they replace beds composed dominantly of clean sand up-dip and/or axially over scales of km to 10s km. In addition to these broad patterns, important yet poorly understood short-length facies changes (over metres to 100s m) occur, modifying the overall texture and reservoir characteristics at or beneath typical spacing of production wells. The nature and origin of the short length-scale transitions is here addressed in four well-exposed HEB-prone outcrops: the Cretaceous-Paleocene Gottero Sandstone and the Miocene Cilento Flysch, both in Italy, the Carboniferous Mam Tor Sandstone in northern England, and the Carboniferous basal Ross Sandstone Formation, Western Ireland. A series of detailed correlation panels show marked lateral variations in internal bed make-up for most of the hybrid event beds studied. This variability typically involves lateral changes in the proportions of the cleaner basal sandstone and the overlying muddy sandstone division that occur without substantial change in the overall event bed thickness. The variability is inferred to reflect the complex fingering between the up-dip sandstone-dominated part of the event bed and the down-dip linked debrite due to internal erosion (ploughing) of the debrite into the basal clean sand. Where the upper part of the bed is dominated by large mudstone rafts, these may have foundered into liquefied sand and been injected and partly fragmented by the sand intrusions. The variable thickness and continuity of the basal clean sandstones have important implications for reservoir characterisation; significant variability in bed character at interwell scale can be anticipated. Rugose contacts between the intra-bed facies divisions may impact on drainage and sweep efficiency during hydrocarbon production

Hybrid Event Beds Generated By Local Substrate Delamination On A Confined-Basin Floor

The outer parts of deep-water fans, and the basin plains into which they pass, are often described as areas where erosion is negligible and turbidite systems have net aggradation. Nevertheless sedimentological and stratigraphic analysis of outer fan lobe and confined basin plain deposits in Cretaceous-Paleocene Gottero Sandstone (NW of Italy) has revealed extensive but cryptic bedding-parallel substrate-delamination features at the base of many sheet-like event beds. These comprise a variety of shallow but wide scour structures showing evidence of lateral expansion by sand-injection. The scours commonly occur at the base of beds made up of a basal clean sandstone overlain by argillaceous sandstone containing abundant mudstone clasts and locally large substrate rafts (up to 20 meters long). These strata are interpreted as a type of hybrid event bed. Field observations suggest that mud-clast entrainment occurred by delamination at the base of dense sandy flows. The large rafts, in some cases only partly detached, were incorporated in the flows locally and then carried for short distances (100s m to a few km) before partly disaggregating and undergoing deformation due to internal shearing. The development of such features may be common in flat and/or confined basin settings where high-volume flows interact with a cohesive and well layered substrate (e.g. muddy outer fans or confined or ponded basins with thick mudstone caps). Delamination is therefore suggested as an alternative mechanism leading to the formation of hybrid event beds following local substrate entrainment on the basin floor as opposed to on more remote slopes and at channel-lobe transition zones

Facies and architecture of a sand-rich turbidite system in an evolving collisional-trench basin: a case history from the upper Cretaceous-Palaeocene Gottero system (Nw apennines)

This study documents the main depositional elements of a dynamically-controlled sand-rich deep-water turbidite system (Upper Cretaceous\u2013Palaeocene Gottero system, north-west Italy). The large exposures and the wide range of facies and deep-water sub-environments recognised, ranging from proximal channels, unconfined proximal and distal lobes and confined basin plain deposits make this an instructive case study to investigate the spatial-temporal relationships between fan features (channels and lobes) and confined to ponded basin-plain deposits developed in a trench-fill basin. The study focus on stratigraphic and palaeo-environmental reconstruction of the Gottero system in the western sector of the basin. Bed types, facies associations and depositional sub-environments are described in main outcrop locations and used to feed a comprehensive bed-scale database. A coherent stratigraphic framework of the system is proposed for the first time, linking its stratigraphic evolution with the collisional-trench context of the Ligurian units during the Upper Cretaceous-Palaeocene. It includes a first stage in which the Gottero was a prograding extensive basin-floor fan developed in a relatively unconfined setting (Gottero 1 and 2), and a second stage in which the system deepens and got progressively confined and segmented in multiple distal depocentres, dominated by sheet-like high magnitude events, meanwhile the proximal area forms a series of fan elements which display an overall retrograding trend (Gottero 3). The basin fill terminates with the deposition of the Giaiette mass-transport complex interepreted to represent the final collapse of the growing Ligurian accrectionary wedge

The preparation of the Shutdown Dose Rate experiment for the next JET Deuterium-Tritium campaign

The assessment of the Shutdown Dose Rate (SDR) due to neutron activation is a major safety issue for fusion devices and in the last decade several benchmark experiments have been conducted at JET during Deuterium-Deuterium experiments for the validation of the numerical tools used in ITER nuclear analyses. The future Deuterium-Tritium campaign at JET (DTE2) will provide a unique opportunity to validate the codes under ITER-relevant conditions through the comparison between numerical predictions and measured quantities (C/E). For this purpose, a novel SDR experiment, described in the present work, is in preparation in the frame of the WPJET3-NEXP subproject within EUROfusion Consortium. The experimental setup has been accurately designed to reduce measurement uncertainties; spherical air-vented ionization chambers (ICs) will be used for on-line ex-vessel decay gamma dose measurements during JET shutdown following DT operations and activation foils have been selected for measuring the neutron fluence near ICs during operations. Active dosimeters (based on ICs) have been calibrated over a broad energy range (from about 30 keV to 1.3 MeV) with X and gamma reference beam qualities. Neutron irradiation tests confirmed the capability of active dosimeters of performing on-line decay gamma dose rate measurements, to follow gamma dose decay at the end of neutron irradiation as well as insignificant activation of the ICs

Gene silencing of endothelial von Willebrand factor reduces the susceptibility of human endothelial cells to SARS-CoV-2 infection

Mechanisms underlying vascular endothelial susceptibility to infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are not fully understood. Emerging evidence indicates that patients lacking von Willebrand factor (vWF), an endothelial hallmark, are less severely affected by SARS-CoV-2 infection, yet the precise role of endothelial vWF in modulating coronavirus entry into endothelial cells is unknown. In the present study, we demonstrated that effective gene silencing by short interfering RNA (siRNA) for vWF expression in resting human umbilical vein endothelial cells (HUVECs) significantly reduced by 56% the cellular levels of SARS-CoV-2 genomic RNA. Similar reduction of intracellular SARS-CoV-2 genomic RNA levels was observed in non-activated HUVECs treated with siRNA targeting angiotensin-converting enzyme 2 (ACE2), the cellular gateway to coronavirus. By integrating quantitative information from real-time PCR and high-resolution confocal imaging, we demonstrated that ACE2 gene expression and its plasma membrane localization in HUVECs were both markedly reduced after treatment with siRNA anti-vWF or anti-ACE2. Conversely, siRNA anti-ACE2 did not reduce endothelial vWF gene expression and protein levels. Finally, SARS-CoV-2 infection of viable HUVECs was enhanced by overexpression of vWF, which increased ACE2 levels. Of note, we found a similar increase in interferon-β mRNA levels following transfection with untargeted, anti-vWF or anti-ACE2 siRNA and pcDNA3.1-WT-VWF. We envision that siRNA targeting endothelial vWF will protect against productive endothelial infection by SARS-CoV-2 through downregulation of ACE2 expression and might serve as a novel tool to induce disease resistance by modulating the regulatory role of vWF on ACE2 expression

Nuclear design of a shielded cabinet for electronics: The ITER radial neutron camera case study

The Radial Neutron Camera (RNC) is a diagnostic system located in ITER Equatorial Port #1 providing several spatial and time-resolved parameters for the fusion power estimation, plasma control and physics studies. The RNC measures the uncollided 14 MeV and 2.5 MeV neutrons from deuterium-tritium (DT) and deuterium deuterium (DD) fusion reactions through an array of neutron flux detectors located in collimated Lines of Sight. Signals from RNC detectors (fission chambers, single Crystal Diamonds and scintillators) need pre amplification because of their low amplitude. These preamplifiers have to be as close as possible to the detectors in order to minimize signal degradation and must be protected against fast and thermal neutrons, gamma radiation and electromagnetic fields. The solution adopted is to host the preamplifiers in a shielded cabinet located in a dedicated area of the Port Cell, behind the Bioshield Plug. The overall design of the cabinet must ensure the necessary magnetic, thermal and nuclear shielding and, at the same, satisfy weight and allocated volume constraints and maintain its structural integrity. The present paper describes the nuclear design of the shielded cabinet, performed by means of 3D particle transport calculations (MCNP), taking into account the radiation streaming through the Bioshield penetrations and the cross-talk effect from the neighboring Lower and Upper Ports. We present the assessment of its nuclear shielding performances and analyze the compliancy with the alert thresholds for commercial electronics in terms of neutron flux and cumulated ionizing dose

Fill to spill stratigraphic evolution of a confined turbidite mini-basin succession, and its likely well bore expression: The Castagnola Fm, NW Italy

This study documents the stratigraphic evolution of the Castagnola ponded turbidite mini-basin through analysis of a detailed base-to-top section measured in the central part of the basin. Vertical variations in facies characteristics, thickness ratio of mud cap vs. sandstone of event beds and net/gross are argued to be good proxies for pinpointing the stratigraphic transition from dominantly ponded deposition, where most of the flow is trapped by the confining topography, to a flow-stripping - dominated phase in which an increasingly large part of incoming flows can escape the basin by spilling over the enclosing topography. Thickness statistics of sandstones and mud caps of event beds from the case study show that in the initial stage of turbidite deposition only part of the mud of exceptionally large volume flows escaped the confining topography; as the basin was progressively infilled, nearly all inbound flows were affected by flow stripping, with part of the sand and most of the mud escaping the basin. In the latest recorded stage of deposition the abundance of by-pass features coupled with significant modification of the sandstone bed thickness population suggests that the turbidite system was no longer obstructed frontally, and could step forward onto a healed topography. In order to assess whether the documented trends of turbidite bed characteristics indicative of the 'fill to spill' transition could be recognised from wireline log data alone, synthetic logs were prepared by up-scaling the field data to resolutions typical of borehole geophysical log data. Vertical trends of average bed thickness and net/gross recognisable in the synthetic data suggest that the transition from ponded to spill-dominated situations should be resolvable in geophysical log data

The electron capture in 163^{163}Ho experiment – ECHo

Neutrinos, and in particular their tiny but non-vanishing masses, can be considered one of the doors towards physics beyond the Standard Model. Precision measurements of the kinematics of weak interactions, in particular of the $^{3}$H β-decay and the $^{163}$Ho electron capture (EC), represent the only model independent approach to determine the absolute scale of neutrino masses. The electron capture in $^{163}$Ho experiment, ECHo, is designed to reach sub-eV sensitivity on the electron neutrino mass by means of the analysis of the calorimetrically measured electron capture spectrum of the nuclide $^{163}$Ho. The maximum energy available for this decay, about 2.8 keV, constrains the type of detectors that can be used. Arrays of low temperature metallic magnetic calorimeters (MMCs) are being developed to measure the $^{163}$Ho EC spectrum with energy resolution below 3 eV FWHM and with a time resolution below 1 μs. To achieve the sub-eV sensitivity on the electron neutrino mass, together with the detector optimization, the availability of large ultra-pure $^{163}$Ho samples, the identification and suppression of background sources as well as the precise parametrization of the $^{163}$Ho EC spectrum are of utmost importance. The high-energy resolution $^{163}$Ho spectra measured with the first MMC prototypes with ion-implanted $^{163}$Ho set the basis for the ECHo experiment. We describe the conceptual design of ECHo and motivate the strategies we have adopted to carry on the present medium scale experiment, ECHo-1K. In this experiment, the use of 1 kBq $^{163}$Ho will allow to reach a neutrino mass sensitivity below 10 eV/c$^{2}$. We then discuss how the results being achieved in ECHo-1k will guide the design of the next stage of the ECHo experiment, ECHo-1M, where a source of the order of 1 MBq $^{163}$Ho embedded in large MMCs arrays will allow to reach sub-eV sensitivity on the electron neutrino mass