Modelling the seasonality of Lyme disease risk and the potential impacts of a warming climate within the heterogeneous landscapes of Scotland

Lyme disease is the most prevalent vector-borne disease in the temperate Northern Hemisphere. The abundance of infected nymphal ticks is commonly used as a Lyme disease risk indicator. Temperature can influence the dynamics of disease by shaping the activity and development of ticks and, hence, altering the contact pattern and pathogen transmission between ticks and their host animals. A mechanistic, agent-based model was developed to study the temperature-driven seasonality of Ixodes ricinus ticks and transmission of Borrelia burgdorferi sensu lato across mainland Scotland. Based on 12-year averaged temperature surfaces, our model predicted that Lyme disease risk currently peaks in autumn, approximately six weeks after the temperature peak. The risk was predicted to decrease with increasing altitude. Increases in temperature were predicted to prolong the duration of the tick questing season and expand the risk area to higher altitudinal and latitudinal regions. These predicted impacts on tick population ecology may be expected to lead to greater tick–host contacts under climate warming and, hence, greater risks of pathogen transmission. The model is useful in improving understanding of the spatial determinants and system mechanisms of Lyme disease pathogen transmission and its sensitivity to temperature changes

Amplitude equations near pattern forming instabilities for strongly driven ferromagnets

A transversally driven isotropic ferromagnet being under the influence of a static external and an uniaxial internal anisotropy field is studied. We consider the dissipative Landau-Lifshitz equation as the fundamental equation of motion and treat it in $1+1$~dimensions. The stability of the spatially homogeneous magnetizations against inhomogeneous perturbations is analyzed. Subsequently the dynamics above threshold is described via amplitude equations and the dependence of their coefficients on the physical parameters of the system is determined explicitly. We find soft- and hard-mode instabilities, transitions between sub- and supercritical behaviour, various bifurcations of higher codimension, and present a series of explicit bifurcation diagrams. The analysis of the codimension-2 point where the soft- and hard-mode instabilities coincide leads to a system of two coupled Ginzburg-Landau equations.Comment: LATeX, 25 pages, submitted to Z.Phys.B figures available via [email protected] in /pub/publications/frank/zpb_95 (postscript, plain or gziped

Magnetic field frustration of the metal-insulator transition in V2 O3

Despite decades of efforts, the origin of metal-insulator transitions (MITs) in strongly correlated materials remains one of the main long-standing problems in condensed-matter physics. An archetypal example is V2O3, which undergoes simultaneous electronic, structural, and magnetic phase transitions. This remarkable feature highlights the many degrees of freedom at play in this material. In this work, acting solely on the magnetic degree of freedom, we reveal an anomalous feature in the electronic transport of V2O3: On cooling, the magnetoresistance changes from positive to negative values well above the MIT temperature, and shows divergent behavior at the transition. The effects are attributed to the magnetic field quenching antiferromagnetic fluctuations above the Néel temperature TN, and preventing long-range antiferromagnetic ordering below TN. In both cases, suppressing the antiferromagnetic ordering prevents the opening of the incipient electronic gap. This interpretation is supported by Hubbard model calculations which fully reproduce the experimental behavior. Our study sheds light on this classic problem providing a clear and physical interpretation of the nature of the metal-insulator transition.Fil: Trastoy, J.. University of California at San Diego; Estados UnidosFil: Camjayi, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Del Valle, J.. University of California at San Diego; Estados UnidosFil: Kalcheim, Y.. University of California at San Diego; Estados UnidosFil: Crocombette, J. P.. Université Paris-Saclay; FranciaFil: Gilbert, D.A.. University of Tennessee; Estados UnidosFil: Borchers, J.A.. Nist Center For Neutron Research; Estados UnidosFil: Villegas, J.E.. Université Paris-Saclay; FranciaFil: Ravelosona, D.. Center For Nanoscience And Nanotechnology; FranciaFil: Rozenberg, M.J.. Université Paris-Saclay; FranciaFil: Schuller, Ivan K.. University of California at San Diego; Estados Unido

Nonlinear interference in a mean-field quantum model

Using similar nonlinear stationary mean-field models for Bose-Einstein Condensation of cold atoms and interacting electrons in a Quantum Dot, we propose to describe the original many-particle ground state as a one-particle statistical mixed state of the nonlinear eigenstates whose weights are provided by the eigenstate non-orthogonality. We search for physical grounds in the interpretation of our two main results, namely, quantum-classical nonlinear transition and interference between nonlinear eigenstates.Comment: RevTeX (pdfLaTeX), 7 pages with 5 png-figures include

Selberg Supertrace Formula for Super Riemann Surfaces III: Bordered Super Riemann Surfaces

This paper is the third in a sequel to develop a super-analogue of the classical Selberg trace formula, the Selberg supertrace formula. It deals with bordered super Riemann surfaces. The theory of bordered super Riemann surfaces is outlined, and the corresponding Selberg supertrace formula is developed. The analytic properties of the Selberg super zeta-functions on bordered super Riemann surfaces are discussed, and super-determinants of Dirac-Laplace operators on bordered super Riemann surfaces are calculated in terms of Selberg super zeta-functions.Comment: 43 pages, amste

Banking union in historical perspective: the initiative of the European Commission in the 1960s-1970s

This article shows that planning for the organization of EU banking regulation and supervision did not just appear on the agenda in recent years with discussions over the creation of the eurozone banking union. It unveils a hitherto neglected initiative of the European Commission in the 1960s and early 1970s. Drawing on extensive archival work, this article explains that this initiative, however, rested on a number of different assumptions, and emerged in a much different context. It first explains that the Commission's initial project was not crisis-driven; that it articulated the link between monetary integration and banking regulation; and finally that it did not set out to move the supervisory framework to the supranational level, unlike present-day developments

Aharonov-Bohm Physics with Spin II: Spin-Flip Effects in Two-dimensional Ballistic Systems

We study spin effects in the magneto-conductance of ballistic mesoscopic systems subject to inhomogeneous magnetic fields. We present a numerical approach to the spin-dependent Landauer conductance which generalizes recursive Green function techniques to the case with spin. Based on this method we address spin-flip effects in quantum transport of spin-polarized and -unpolarized electrons through quantum wires and various two-dimensional Aharonov-Bohm geometries. In particular, we investigate the range of validity of a spin switch mechanism recently found which allows for controlling spins indirectly via Aharonov-Bohm fluxes. Our numerical results are compared to a transfer-matrix model for one-dimensional ring structures presented in the first paper (Hentschel et al., submitted to Phys. Rev. B) of this series.Comment: 29 pages, 15 figures. Second part of a series of two article