Interpreting early land management through compound specific stable isotope analyses of archaeological soils

Compound specific stable isotope analyses of managed soils using isotope ratio mass spectrometry have been undertaken as a means of determining early land use practices. delta (15)N amino acid signals demonstrate differences between manured grassland, unmanured grassland and continuous cereal cultivation under long-term experimental land use control conditions, with delta (15)N in hydrophobic amino acids providing the most distinctive signals. Analysis of early modern/medieval and of Bronze age anthropogenic soils from Orkney demonstrates that such signals are retained in archaeological contexts. delta (13)C analyses of n- alkanoic acid components of the fossil, Bronze Age, anthropogenic soils suggest a major terrestrial input to these soils, with uniform composition of formation materials. Surficial soils demonstrate the assimilation of isotopically lighter carbon, providing a means of assessing the mobility of the n- alkanoic acids within soils and sediments. Copyright 1999 John Wiley & Sons, Ltd.     

Rotational bands in 167Hf

High-spin states in ¹⁶⁷Hf, populated in the ¹⁴¹Pr(³⁰Si, p3n)¹⁶⁷Hf reaction, have been studied using the nordball Ge detector array. Three rotational cascades have been observed for the first time and the previously-known level scheme has been extended to significantly higher spin. Band-crossing effects are discussed within the framework of Woods-Saxon cranking calculations and are found to be in good agreement. Received: 9 April 1999 / Revised version: 13 May 1999     

Towards immunoassay in whole blood: separationless sandwich-type electrochemical immunoassay based on in-situ generation of the substrate of the labeling enzyme

An 18 minute separationless amperometric ELISA-type sandwich immunoassay, utilizing only stable reagents and having no washing steps is described. The platform for the assay was an electron conducting redox hydrogel on a vitreous carbon electrode. Avidin and choline oxidase were co-immobilized on the redox hydrogel and the biotinylated antibody to the antigen to be assayed (the biotin-labeled F(ab′)₂ fragment of goat anti-rabbit IgG) was bound to the gel. When the antigen (goat anti-rabbit IgG) was present in the analyzed solution, then its binding to the immobilized antibody made the electrode receptive to the complementary peroxidase-labeled antibody (horseradish peroxidase-labeled F(ab′)₂ fragment of goat anti-rabbit IgG). Its binding resulted in electrical contact (“wiring”) of the horseradish peroxidase label to the redox hydrogel, and converted the non-catalytic hydrogel into an electrocatalyst for the reduction of hydrogen peroxide to water at –0.07 V (SCE) and resulted in the flow of a cathodic current. The electroreduced hydrogen peroxide was not added to the solution and was therefore not significantly accessible to hydrogen peroxide decomposing agents such as catalase. Instead, it was generated within the coating of the electrode through reacting dissolved choline with oxygen. This reaction was catalyzed by the immobilized choline oxidase. The reaction centers of choline oxidase, unlike those of horseradish peroxidase, are not connected to the electrode by the redox hydrogel.     

Correlations,Information Backflow,and Objectivity in a Class of Pure Dephasing Models

We critically examine the role that correlations established between a system and fragments of its environment play in characterising the ensuing dynamics. We employ a dephasing model with different initial conditions, where the state of the initial environment represents a tunable degree of freedom that qualitatively and quantitatively affects the correlation profiles, but nevertheless results in the same reduced dynamics for the system. We apply recently developed tools for the characterisation of non-Markovianity to carefully assess the role that correlations, as quantified by the (quantum) Jensen–Shannon divergence and relative entropy, as well as changes in the environmental state, play in whether the conditions for classical objectivity within the quantum Darwinism paradigm are met. We demonstrate that for precisely the same non-Markovian reduced dynamics of the system arising from different microscopic models, some exhibit quantum Darwinistic features, while others show that no meaningful notion of classical objectivity is present. Furthermore, our results highlight that the non-Markovian nature of an environment does not a priori prevent a system from redundantly proliferating relevant information, but rather it is the system’s ability to establish the requisite correlations that is the crucial factor in the manifestation of classical objectivity.     

Review of LDA and PIV applied to the measurement of sound and acoustic streaming

A review of laser Doppler anemometry (LDA) and particle image velocimetry (PIV) with their application to the measurement of sound is presented. The fundamental principles behind LDA and PIV are discussed and extended to the application of sound measurement. Special attention is paid to analysis of LDA signals including the Hilbert transform, which enables amplitude information to be obtained about various frequency components of a signal and wavelet analysis, which allows non-stationary signals to be accurately analysed. The influence of the refractive index variations in a medium due to a sound wave on the laser beams of an LDA signal is discussed. Attention is also paid to acoustic streaming which arises due to high-intensity sound, and PIV results are presented to demonstrate the effect.     

Single-Crystal X-Ray Diffraction Study of Pressure and Temperature-Induced Spin Trapping in a Bistable Iron(II) Hofmann Framework

High-pressure single-crystal X-ray diffraction has been used to trap both the low-spin (LS) and high-spin (HS) states of the iron(II) Hofmann spin crossover framework, [Fe^II(pdm)(H₂O)[Ag(CN)₂]₂⋅H₂O, under identical experimental conditions, allowing the structural changes arising from the spin-transition to be deconvoluted from previously reported thermal effects.