Infections due to Actinobacillus actinomycetemcomitans

Three cases are described which show the typical range of infections which may be caused by Actinobacillus actinomycetemcomitans. namely an actinomycosis-like infection. a prosthetic cardiac valve endocarditrs and a post-traumatic soft-tissue infection. Cultural studies are detailed. and a short review of the disease-producing potential of this organism and its treatment is presented

Measuring Black Hole Spin using X-ray Reflection Spectroscopy

I review the current status of X-ray reflection (a.k.a. broad iron line) based black hole spin measurements. This is a powerful technique that allows us to measure robust black hole spins across the mass range, from the stellar-mass black holes in X-ray binaries to the supermassive black holes in active galactic nuclei. After describing the basic assumptions of this approach, I lay out the detailed methodology focusing on "best practices" that have been found necessary to obtain robust results. Reflecting my own biases, this review is slanted towards a discussion of supermassive black hole (SMBH) spin in active galactic nuclei (AGN). Pulling together all of the available XMM-Newton and Suzaku results from the literature that satisfy objective quality control criteria, it is clear that a large fraction of SMBHs are rapidly-spinning, although there are tentative hints of a more slowly spinning population at high (M>5*10^7Msun) and low (M<2*10^6Msun) mass. I also engage in a brief review of the spins of stellar-mass black holes in X-ray binaries. In general, reflection-based and continuum-fitting based spin measures are in agreement, although there remain two objects (GROJ1655-40 and 4U1543-475) for which that is not true. I end this review by discussing the exciting frontier of relativistic reverberation, particularly the discovery of broad iron line reverberation in XMM-Newton data for the Seyfert galaxies NGC4151, NGC7314 and MCG-5-23-16. As well as confirming the basic paradigm of relativistic disk reflection, this detection of reverberation demonstrates that future large-area X-ray observatories such as LOFT will make tremendous progress in studies of strong gravity using relativistic reverberation in AGN.Comment: 19 pages. To appear in proceedings of the ISSI-Bern workshop on "The Physics of Accretion onto Black Holes" (8-12 Oct 2012). Revised version adds a missing source to Table 1 and Fig.6 (IRAS13224-3809) and corrects the referencing of the discovery of soft lags in 1H0707-495 (which were in fact first reported in Fabian et al. 2009

Scale-invariant moving finite elements for nonlinear partial differential equations in two dimensions

A scale-invariant moving finite element method is proposed for the adaptive solution of nonlinear partial differential equations. The mesh movement is based on a finite element discretisation of a scale-invariant conservation principle incorporating a monitor function, while the time discretisation of the resulting system of ordinary differential equations is carried out using a scale-invariant time-stepping which yields uniform local accuracy in time. The accuracy and reliability of the algorithm are successfully tested against exact self-similar solutions where available, and otherwise against a state-of-the-art h-refinement scheme for solutions of a two-dimensional porous medium equation problem with a moving boundary. The monitor functions used are the dependent variable and a monitor related to the surface area of the solution manifold

Atomic X-ray Spectroscopy of Accreting Black Holes

Current astrophysical research suggests that the most persistently luminous objects in the Universe are powered by the flow of matter through accretion disks onto black holes. Accretion disk systems are observed to emit copious radiation across the electromagnetic spectrum, each energy band providing access to rather distinct regimes of physical conditions and geometric scale. X-ray emission probes the innermost regions of the accretion disk, where relativistic effects prevail. While this has been known for decades, it also has been acknowledged that inferring physical conditions in the relativistic regime from the behavior of the X-ray continuum is problematic and not satisfactorily constraining. With the discovery in the 1990s of iron X-ray lines bearing signatures of relativistic distortion came the hope that such emission would more firmly constrain models of disk accretion near black holes, as well as provide observational criteria by which to test general relativity in the strong field limit. Here we provide an introduction to this phenomenon. While the presentation is intended to be primarily tutorial in nature, we aim also to acquaint the reader with trends in current research. To achieve these ends, we present the basic applications of general relativity that pertain to X-ray spectroscopic observations of black hole accretion disk systems, focusing on the Schwarzschild and Kerr solutions to the Einstein field equations. To this we add treatments of the fundamental concepts associated with the theoretical and modeling aspects of accretion disks, as well as relevant topics from observational and theoretical X-ray spectroscopy.Comment: 63 pages, 21 figures, Einstein Centennial Review Article, Canadian Journal of Physics, in pres

Surface hydrology, sediment transport dynamics, and remote sensing of disturbed watersheds in a humid temperature region

The specific objectives of this research are to quantify relationships between surface spectral properties and infiltration capacity explore the interaction between surface hydrology and basin morphology, specifically drainage network morphology, and develop a comprehensive process-response model for drainage basin evolution. This research examines the response of the drainage network and drainage basin water discharge to changes in the dominant processes that control infiltration and runoff, namely macropore network development. Infiltration, the primary regulator of runoff, is analyzed with respect to surface spectral characteristics and drainage basin water discharge. Changes in basin discharge measured on a storm event basis in the field are supplemented with simulated discharge events using a distributed hydrologic model. The hydrologic model is evaluated and parameterized by means of a detailed sensitivity analysis. The response of drainage basin water discharge to charges in infiltration properties of minesoils, and the inferred runoff process, and drainage network morphology is examined. The threshold discharge, or stream power, for sediment entrainment and the implications for changes in sediment discharge through time is also discussed. Ritter and Gardner conclude with a process-response model for drainage basin evolution, with implications for natural drainage basin response to climate change. Finally, basic rainfall-runoff relationships developed will be applied to an empirical method for predicting discharge on reclaimed surface mines and compared to standard relationships presently used for discharge prediction. 17 refs., 6 figs., 2 tabs

Comproportionation of CO2 and Cellulose to Formate Using a Floating Semiconductor-Enzyme Photoreforming Catalyst

Funding Information: We would like to thank the European Research Council (ERC) for a Proof of Concept Grant (SolReGen; to E.L. and E.R.) and a Consolidator Grant (MatEnSAP; to M.M. and E.R.), the Swiss National Science Foundation (Early Postdoc Fellowship: P2EZP2 191791 to E.L.) as well as the National Science and Engineering Research Council of Canada (NSERC) for a Postdoctoral Fellowship (S.L.). We thank also Fundação para a Ciência e Tecnologia (Portugal) for fellowship DFA/BD/7897/2020 (R.M.), grant PTDC/BII-BBF/2050/2020 (I.A.C.P.), MOSTMICRO-ITQB unit (UIDB/04612/2020 and UIDP/04612/2020) and Associated Laboratory LS4FUTURE (LA/P/0087/2020). Ariffin Mohamad Annuar, Subhajit Bhattacharjee, Dongseok Kim (University of Cambridge) and Victor Mougel (ETH Zürich) are acknowledged for helpful discussions. Funding Information: We would like to thank the European Research Council (ERC) for a Proof of Concept Grant (SolReGen; to E.L. and E.R.) and a Consolidator Grant (MatEnSAP; to M.M. and E.R.), the Swiss National Science Foundation (Early Postdoc Fellowship: P2EZP2 191791 to E.L.) as well as the National Science and Engineering Research Council of Canada (NSERC) for a Postdoctoral Fellowship (S.L.). We thank also Fundação para a Ciência e Tecnologia (Portugal) for fellowship DFA/BD/7897/2020 (R.M.), grant PTDC/BII‐BBF/2050/2020 (I.A.C.P.), MOSTMICRO‐ITQB unit (UIDB/04612/2020 and UIDP/04612/2020) and Associated Laboratory LS4FUTURE (LA/P/0087/2020). Ariffin Mohamad Annuar, Subhajit Bhattacharjee, Dongseok Kim (University of Cambridge) and Victor Mougel (ETH Zürich) are acknowledged for helpful discussions. Publisher Copyright: © 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.Formate production via both CO2 reduction and cellulose oxidation in a solar-driven process is achieved by a semi-artificial biohybrid photocatalyst consisting of immobilized formate dehydrogenase on titanium dioxide (TiO2|FDH) producing up to 1.16±0.04 mmolformate g (Formula presented.) −1 in 24 hours at 30 °C and 101 kPa under anaerobic conditions. Isotopic labeling experiments with 13C-labeled substrates support the mechanism of stoichiometric formate formation through both redox half-reactions. TiO2|FDH was further immobilized on hollow glass microspheres to perform more practical floating photoreforming allowing vertical solar light illumination with optimal light exposure of the photocatalyst to real sunlight. Enzymatic cellulose depolymerization coupled to the floating photoreforming catalyst generates 0.36±0.04 mmolformate per m2 irradiation area after 24 hours. This work demonstrates the synergistic solar-driven valorization of solid and gaseous waste streams using a biohybrid photoreforming catalyst in aqueous solution and will thus provide inspiration for the development of future semi-artificial waste-to-chemical conversion strategies.publishersversionpublishe

Quantum Lattice Solitons

The number state method is used to study soliton bands for three anharmonic quantum lattices: i) The discrete nonlinear Schr\"{o}dinger equation, ii) The Ablowitz-Ladik system, and iii) A fermionic polaron model. Each of these systems is assumed to have $f$-fold translational symmetry in one spatial dimension, where $f$ is the number of freedoms (lattice points). At the second quantum level $(n=2)$ we calculate exact eigenfunctions and energies of pure quantum states, from which we determine binding energy $(E_{\rm b})$, effective mass $(m^{*})$ and maximum group velocity $(V_{\rm m})$ of the soliton bands as functions of the anharmonicity in the limit $f \to \infty$. For arbitrary values of $n$ we have asymptotic expressions for $E_{\rm b}$, $m^{*}$, and $V_{\rm m}$ as functions of the anharmonicity in the limits of large and small anharmonicity. Using these expressions we discuss and describe wave packets of pure eigenstates that correspond to classical solitons.Comment: 21 pages, 1 figur