Chemical signatures of the Anthropocene in the Clyde Estuary, UK: sediment hosted Pb, 207/206 Pb, Total Petroleum Hydrocarbons (TPH), Polyaromatic Hydrocarbon (PAH) and Polychlorinated Bipheny (PCB) pollution records

The sediment concentrations of total petroleum hydrocarbons (TPHs), polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), Pb and 207/206Pb isotope ratios were measured in seven cores from the middle Clyde estuary (Scotland, UK) with an aim of tracking the late Anthropocene. Concentrations of TPHs ranged from 34 to 4386 mg kg−1, total PAHs from 19 to 16 163 μg kg−1 and total PCBs between less than 4.3 to 1217 μg kg−1. Inventories, distributions and isomeric ratios of the organic pollutants were used to reconstruct pollutant histories. Pre-Industrial Revolution and modern non-polluted sediments were characterized by low TPH and PAH values as well as high relative abundance of biogenic-sourced phenanthrene and naphthalene. The increasing industrialization of the Clyde gave rise to elevated PAH concentrations and PAH isomeric ratios characteristic of both grass/wood/coal and petroleum and combustion (specifically petroleum combustion). Overall, PAHs had the longest history of any of the organic contaminants. Increasing TPH concentrations and a concomitant decline in PAHs mirrored the lessening of coal use and increasing reliance on petroleum fuels from about the 1950s. Thereafter, declining hydrocarbon pollution was followed by the onset (1950s), peak (1965–1977) and decline (post-1980s) in total PCB concentrations. Lead concentrations ranged from 6 to 631 mg kg−1, while 207/206Pb isotope ratios spanned 0.838–0.876, indicative of various proportions of ‘background’, British ore/coal and Broken Hill type petrol/industrial lead. A chronology was established using published Pb isotope data for aerosol-derived Pb and applied to the cores

Criticality in coupled quantum spin-chains with competing ladder-like and two-dimensional couplings

Motivated by the geometry of spins in the material CaCu$_2$O$_3$, we study a two-layer, spin-half Heisenberg model, with nearest-neighbor exchange couplings J and \alpha*J along the two axes in the plane and a coupling J_\perp perpendicular to the planes. We study these class of models using the Stochastic Series Expansion (SSE) Quantum Monte Carlo simulations at finite temperatures and series expansion methods at T=0. The critical value of the interlayer coupling, J_\perp^c, separating the N{\'e}el ordered and disordered ground states, is found to follow very closely a square root dependence on $\alpha$. Both T=0 and finite-temperature properties of the model are presented.Comment: 9 pages, 11 figs., 1 tabl

Hawking Radiation from Non-Extremal D1-D5 Black Hole via Anomalies

We take the method of anomaly cancellation for the derivation of Hawking radiation initiated by Robinson and Wilczek, and apply it to the non-extremal five-dimensional D1-D5 black hole in string theory. The fluxes of the electric charge flow and the energy-momentum tensor from the black hole are obtained. They are shown to match exactly with those of the two-dimensional black body radiation at the Hawking temperature.Comment: 14 page

Specific heat of quasi-2D antiferromagnetic Heisenberg models with varying inter-planar couplings

We have used the stochastic series expansion (SSE) quantum Monte Carlo (QMC) method to study the three-dimensional (3D) antiferromagnetic Heisenberg model on cubic lattices with in-plane coupling J and varying inter-plane coupling J_perp < J. The specific heat curves exhibit a 3D ordering peak as well as a broad maximum arising from short-range 2D order. For J_perp << J, there is a clear separation of the two peaks. In the simulations, the contributions to the total specific heat from the ordering across and within the layers can be separated, and this enables us to study in detail the 3D peak around T_c (which otherwise typically is dominated by statistical noise). We find that the peak height decreases with decreasing J_perp, becoming nearly linear below J_perp = 0.2J. The relevance of these results to the lack of observed specific heat anomaly at the ordering transition of some quasi-2D antiferromagnets is discussed.Comment: 7 pages, 8 figure

How does successive inpatriation contribute to subsidiary capability building and subsidiary evolution? An organizational knowledge creation perspective

Intra-company knowledge transfer is a key source of competitive advantage for multinational companies (MNCs) and this knowledge is usually embedded in individuals. Drawing on organizational knowledge creation theory, we explore how inpatriation contributes to knowledge transfer and, in turn, subsidiary performance. Inpatriation involves the international assignment of employees from an MNC’s foreign subsidiary to its headquarters. Despite increasing attention to the role of inpatriation, we lack a clear understanding of whether and how inpatriates provide value to their subsidiaries after returning from headquarters. Through a qualitative case study of Japanese MNCs, we demonstrate the process through which inpatriates’ knowledge transfer contributes to subsidiary capability building and subsidiary evolution over time, and explain why successive inpatriation is thus critical to enhance subsidiary performance. Our theoretical model highlights the value of inpatriates as knowledge agents, reveals the process through which inpatriates transfer knowledge between HQ and subsidiaries, and provides a more nuanced understanding of the micro-foundations of intra-MNC knowledge transfer processes. Based on these findings, we argue that inpatriation is not merely a staffing method that is complementary to expatriation, but a key practice in its own right to support subsidiaries’ growth and performance

Quantum Monte Carlo simulation for the conductance of one-dimensional quantum spin systems

Recently, the stochastic series expansion (SSE) has been proposed as a powerful MC-method, which allows simulations at low $T$ for quantum-spin systems. We show that the SSE allows to compute the magnetic conductance for various one-dimensional spin systems without further approximations. We consider various modifications of the anisotropic Heisenberg chain. We recover the Kane-Fisher scaling for one impurity in a Luttinger-liquid and study the influence of non-interacting leads for the conductance of an interacting system.Comment: 8 pages, 9 figure

Composite vertices that lead to soft form factors

The momentum-space cut-off parameter $\Lambda$ of hadronic vertex functions is studied in this paper. We use a composite model where we can measure the contributions of intermediate particle propagations to $\Lambda$. We show that in many cases a composite vertex function has a much smaller cut-off than its constituent vertices, particularly when light constituents such as pions are present in the intermediate state. This suggests that composite meson-baryon-baryon vertex functions are rather soft, i.e., they have \Lambda considerably less than 1 GeV. We discuss the origin of this softening of form factors as well as the implications of our findings on the modeling of nuclear reactions.Comment: REVTex, 19 pages, 5 figs(to be provided on request

Organic geochemistry of Palaeozoic Source Rocks of the Irish Sea, UK

The East Irish Sea gas and oil fields (Triassic reservoir e.g. Morecambe, Lennox) are believed to be sourced from the underlying Carboniferous strata (e.g. Armstrong et al., 1997; Quirk et al. 1999 and references therein). This study undertook a systematic screening of Rock-Eval and vitrinite reflectance data extracted from released legacy well reports with the aim of providing a data based, regional overview of Carboniferous source rock intervals and their levels of maturity in the wider Irish Sea study area. The method and description of calculated parameters used are given in Vane et al. (2015). The Palaeozoic stratigraphy of the region is described in Wakefield et al. (2016b) and the regional petroleum systems analysis in Pharaoh et al. (2016). Released geochemical data from the Palaeozoic of the Irish Sea is sparse and a variety of stratigraphical units have been sampled, mostly from units other than the likely main source rock interval (Bowland Shale Formation and equivalents). Nine wells were evaluated: 110/02b-10, 110/07-2, 110/07b-6, 110/09a-2, 111/25-1A, 113/27-1, 113/27-2 and 113/27-3. Well 110/12a-1 was not assessed due to the absence of key maturity information. In these wells, the Pennine Lower Coal Measures, Millstone Grit Group and Bowland Shale Formation are mainly gas-prone strata of poor-fair generative potential remaining and mature to the gas window at the sampled intervals in Quadrants 110 and 113 (Figure 1). Within the limited well sample set examined, high Total Organic Carbon (TOC) coal intervals have the best generative potential remaining. The Cumbrian Coastal Group, Appleby Group and Carboniferous Limestone Supergroup present in two wells in Quadrant 111 are at oil to gas window maturity levels, but have low TOC and low residual hydrocarbon generative potential

UK Geoenergy Observatories, Glasgow environmental baseline soil chemistry dataset

This report describes the environmental baseline topsoil chemistry dataset collected in February-March 2018 (03-18) as part of the United Kingdom Geoenergy Observatories (UKGEOS) project. Ninety, samples were collected from the shallow coal-mine Glasgow Geothermal Energy Research Field Site (GGERFS). The report accompanies the GGERFS Soil Chemistry03-18 dataset. It provides valuable information on soil chemistry prior to installation of the GGERFS-facility boreholes, against which any future change during the development/ running of the facility can be assessed. This information is necessary to help understand and de-risk similar shallow geothermal schemes in the future, provide public reassurance, and inform sustainable energy policy

Equal abundance of odd and even n-alkanes from cycad leaves: can the carbon preference index (CPI) faithfully record terrestrial organic matter input at low latitudes?

Long chain n-alkanes from the leaves of thirteen extant cycad species within the Cycadacaea, Stangeriaceae, Zamiaceae families were measured by gas chromatographymass spectrometry (GC-MS). Cycad n-alkane patterns ranged from nC10-nC37, were unimodal in distribution, maximised at nC27-nC33 and gave average chain length (ACL) values of 23.9 to 31.0. Low carbon preference indices (CPI) in the range of 0.88 to 2.70 were observed which is atypical of lipids from the leaves of terrestrial plants. Analysis of variance between the three families of true cycads showed that there were no significant differences between CPI values. The unusually low CPI values (<1.5) in nine of the thirteen cycad species analysed suggests that caution needs to be exercised in the use of n-alkanes distibutions as a chemical marker of terrestrial plant input in sediments from tropical and sub-tropical regions