648 research outputs found
Anomalous enrichment of molybdenum and associated metals in Lower Jurassic (Lias Group) black shales of central England, as revealed by systematic geochemical surveys
Systematic multi-media geochemical surveying by the British Geological Survey's Geochemical Baseline Survey of the Environment (G-BASE) project has revealed significant anomalous patterns of enrichment for a suite of elements â copper (Cu) and uranium (U) â with exceptionally high levels of molybdenum (Mo), in soils and stream sediments in central England. Enrichment of these elements is most often associated with organic-rich, sulphidic âblack shaleâ lithofacies, typical of oxygen-deficient, euxinic depositional environments. The main anomaly lies between Evesham and Rugby where the bedrock comprises the Blue Lias and Charmouth Mudstone formations. Concentrations of Mo are particularly high, reaching soil values of 50 mg/kg, where the regional background is <2 mg/kg. Analysis of black shale partings sampled from rhythmic limestoneâshale couplets reveal Mo levels up to 320 mg/kg. Complementary X-ray diffraction analyses suggest that the anomalous Mo levels are hosted by sulphidic (pyrite) rather than organic phases. High Mo levels may have significant impacts on local agriculture, as well as revealing hitherto unsuspected periods of hypoxic and anoxic bottom water sedimentation within localised basins in central England during the Early Jurassic. Rhythmic alternations of thin beds of Mo-rich, sulphidic black shale (euxinic) with bioclastic and micritic limestone (oxic) represent primary depositional cycles rather than a diagenetic origin. The bed-scale cyclicity is attributed to previously described orbitally-induced precession cycles that influenced climate. These resulted in periods of basin anoxia and black shale sedimentation during periods of enhanced terrestrial fresh-water run-off (possibly below a low-salinity pycnocline), alternating with periods of oxygenation of the sea-water and bottom sediments during overturn of the water column
Detecting autoreactive B cells in the peripheral blood of people with type 1 diabetes using ELISpot
Type 1 diabetes mellitus (T1D) is an autoimmune disorder where T lymphocytes damage the islet beta cells but B lymphocytes also play an important role. Although changes in peripheral B cell phenotype have been observed, little is known about the B cells that secrete the autoantibodies. We developed a sensitive B cell enzyme-linked immunospot assay (ELISpot assay) to detect individual B cell antibody responses to glutamic acid decarboxylase (GAD) and islet antigen-2 (IA-2). We found that even healthy donors have B cells that secrete antibodies in response to GAD and IA-2 in the ELISpot. There was increased B cell reactivity to autoantigens in the peripheral blood of individuals with newly-diagnosed, but not long-standing, type 1 diabetes. However, no correlation with serum autoantibody levels was found, indicating that additional factors such as antigen affinity or exposure to antigens in vivo are required for antibody secretion, and that even healthy donors have potentially autoreactive B cells
The mobilising effect of political choice
Political choice is central to citizensâ participation in elections. Nonetheless, little is known about the individual-level mechanisms that link political choice and turnout. It is argued in this article that turnout decisions are shaped not only by the differences between the parties (party polarisation), but also by the closeness of parties to citizensâ own ideological position (congruence), and that congruence matters more in polarised systems where more is at stake. Analysing cross-national survey data from 80 elections, it is found that both polarisation and congruence have a mobilising effect, but that polarisation moderates the effect of congruence on turnout. To further explore the causal effect of political choice, the arrival of a new radical right-wing party in Germany, the Alternative for Germany (AfD), is leveraged and the findings show that the presence of the AfD had a mobilising effect, especially for citizens with congruent views
The effect of laser transformation notching on the controlled fracture of a high carbon (C70S6 ) steel
A high carbon (C70S6) steel has been laser surface treated using CO2 and Diode lasers in order to produce an embrittled region to act as a fracture notch. Such a process has been investigated as a precursor to the fracture splitting of automotive engine connecting rods. Microstructures of the treated regions have been examined and the fracture behaviour of notched samples has been quantified.
Depending on the laser processing parameters used, the laser transformation notch (LTN) undergoes either solid state transformations or a mixture of melting and solid state transformations. The effect of LTN depth on the peak impact force, the crack initiation energy and Charpy fracture energy was investigated on a C70S6 carbon steel using an instrumented Charpy impact facility. It was reduced to a value < 3.5 J by a LTN of ~ 0.5 mm in depth. Fracture mechanics models indicate that such a LTN can behave in a similar way to a fatigue created crack used in fracture toughness testing ie the LTN behaves as a sharp crack.
Obtaining a sharp crack effect from a LTN is attributable to a combination of: a) the presence of brittle martensite, b) intergranular cracking of favourably oriented columnar grains after melting with inclusions and defects at their boundaries, c) intergranular cracking of coarse grains produced by a high austenitising temperatures and d) minor or major cracks sometimes resulting in centre â line cracking which arises during solidification. LTN was thus shown to have the potential to lead to an effective means of obtaining consistent fracture splitting of connecting rods
Financial diversification before modern portfolio theory: UK financial advice documents in the late nineteenth and the beginning of the twentieth century
The paper offers textual evidence from a series of financial advice documents in the late nineteenth century and the early twentieth century of how UK investors perceived of and managed risk. In the worldâs largest financial centre of the time, UK investors were familiar with the concept of correlation and financial advisersâ suggestions were consistent with the recommendations of modern portfolio theory in relation to portfolio selection strategies. From the 1870s, there was an increased awareness of the benefits of financial diversification - primarily putting equal amounts into a number of different securities - with much of the emphasis being on geographical rather than sectoral diversification and some discussion of avoiding highly correlated investments. Investors in the past were not so naĂŻve as mainstream financial discussions suggest today
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A multilevel neo-institutional analysis of infection prevention and control in English hospitals: coerced safety culture change?
Despite committed policy, regulative and professional efforts on healthcare safety, little is known about how such macro-interventions permeate organisations and shape culture over time. Informed by neo-institutional theory, we examined how inter-organisational influences shaped safety practices and inter-subjective meanings following efforts for coerced culture change. We traced macro-influences from 2000 to 2015 in infection prevention and control (IPC). Safety perceptions and meanings were inductively analysed from 130 in-depth qualitative interviews with senior- and middle-level managers from 30 English hospitals. A total of 869 institutional interventions were identified; 69% had a regulative component. In this context of forced implementation of safety practices, staff experienced inherent tensions concerning the scope of safety, their ability to be open and prioritisation of external mandates over local need. These tensions stemmed from conflicts among three co-existing institutional logics prevalent in the NHS. In response to requests for change, staff flexibly drew from a repertoire of cognitive, material and symbolic resources within and outside their organisations. They crafted 'strategies of action', guided by a situated assessment of first-hand practice experiences complementing collective evaluations of interventions such as 'pragmatic', 'sensible' and also 'legitimate'. Macro-institutional forces exerted influence either directly on individuals or indirectly by enriching the organisational cultural repertoire
A rapid staining technique for the detection of the initiation of germination of bacterial spores
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75645/1/j.1472-765x.2002.01047.x.pd
DNA methylation is required to maintain both DNA replication timing precision and 3D genome organization integrity
DNA replication timing and three-dimensional (3D) genome organization are associated with distinct epigenome patterns across large domains. However, whether alterations in the epigenome, in particular cancer-related DNA hypomethylation, affects higher-order levels of genome architecture is still unclear. Here, using Repli-Seq, single-cell Repli-Seq, and Hi-C, we show that genome-wide methylation loss is associated with both concordant loss of replication timing precision and deregulation of 3D genome organization. Notably, we find distinct disruption in 3D genome compartmentalization, striking gains in cell-to-cell replication timing heterogeneity and loss of allelic replication timing in cancer hypomethylation models, potentially through the gene deregulation of DNA replication and genome organization pathways. Finally, we identify ectopic H3K4me3-H3K9me3 domains from across large hypomethylated domains, where late replication is maintained, which we purport serves to protect against catastrophic genome reorganization and aberrant gene transcription. Our results highlight a potential role for the methylome in the maintenance of 3D genome regulation
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