Finite-Size Effects in the Interface of 3D Ising Model

The interface between domains of opposite magnetization in the 3D Ising model near the critical temperature displays universal finite-size effects which can be described in terms of a gaussian model of capillary waves. It turns out that these finite-size corrections depend rather strongly on the shape of the lattice. This prediction, which has no adjustable parameters, is tested and accurately verified for various lattice shapes by means of numerical simulations with a cluster algorithm. This supports also a long-standing conjecture on the finite-size effects in Wilson loops of Lattice Gauge Theories.Comment: 13 pages, plain latex, two figures not included, sorry DFTT 68/9

The Topological Susceptibility of the Lattice CP(n-1) Model on the Torus and the Sphere

The topological vacuum structure of the two-dimensional $~CP^{n-1}~$ model for $~n = 3,5,7~$ is studied on the lattice. In particular we investigate the small-volume limit on the torus as well as on the sphere and compare with continuum results. For $~n \ge 5~$ , where lattice artifacts should be suppressed, the topological susceptibility shows unexpectedly strong deviations from asymptotic scaling. On the other hand there is an indication for a convergence to values obtained analytically within the limit $~n \rightarrow \infty~$ .Comment: 20 pages, 14 figures not included, sorry, HU Berlin-IEP-92/2, Nucl. Phys. B in prin

Comparison of Monte Carlo Results for the 3D Ising Interface Tension and Interface Energy with (Extrapolated) Series Expansions

We compare Monte Carlo results for the interface tension and interface energy of the 3-dimensional Ising model with Pad\'e and inhomogeneous differential approximants of the low temperature series that was recently extended by Arisue to $17^{\rm th}$ order in $u=\exp(-4\beta)$. The series is expected to suffer from the roughening singularity at $u\approx 0.196$. The comparison with the Monte Carlo data shows that the Pad\'e and inhomogeneous differential approximants fail to improve the truncated series result of the interface tension and the interface energy in the region around the roughening transition. The Monte Carlo data show that the specific heat displays a peak in the smooth phase. Neither the truncated series nor the Pad\'e approximants find this peak. We also compare Monte Carlo data for the energy of the ASOS model with the corresponding low temperature series that we extended to order $u^{12}$.Comment: 22 pages, 9 figures appended as 3 PS-files, preprints CERN-TH.7029/93, MS-TPI-93-0

Rediscovery and Canonization: The Roman Classics in the Middle Ages

Issue 3 of Interfaces: A Journal of Medieval European Literatures explores the theme of the rediscovery and canonization of the Roman classics in medieval Western European literary culture, beginning in the eleventh century and reaching a wide impact on literary and intellectual life in the twelfth century. It is headed by an article by Birger Munk Olsen whose immense and comprehensive work of cataloguing and analyzing the entire record of manuscripts containing Roman classics copied before 1200 is nearing completion (L‘étude des auteurs classiques aux XIe et XIIe siècles, 5 vols). Within our journal’s scope of medieval European literature we have found it both rewarding and fitting to take Munk Olsen’s work as a prism for what is a striking literary phenomenon across most geographies and chronologies of medieval Europe: the engagement with the pre-Christian classics.The catalogue and the synthesis by Munk Olsen put many kinds of new studies on a firm footing. In this issue of Interfaces we present three 'frontiers' or types of scholarship on the rediscovery and canonization of the Roman classics all taking their cue from the meticulous way L’étude has charted out this territory

A Numerical Transfer-Matrix Study of Surface-Tension Anisotropy in Ising Models on Square and Cubic Lattices

We compute by numerical transfer-matrix methods the surface free energy $\tau(T),$ the surface stiffness coefficient $\kappa(T),$ and the single-step free energy $s(T)$ for Ising ferromagnets with $(\infty \times L)$ square-lattice and $(\infty \times L \times M)$ cubic-lattice geometries, into which an interface is introduced by imposing antiperiodic or plus/minus boundary conditions in one transverse direction. These quantities occur in expansions of the angle-dependent surface tension, either for rough or for smooth interfaces. The finite-size scaling behavior of the interfacial correlation length provides the means of investigating $\kappa(T)$ and $s(T).$ The resulting transfer-matrix estimates are fully consistent with previous series and Monte Carlo studies, although current computational technology does not permit transfer-matrix studies of sufficiently large systems to show quantitative improvement over the previous estimates.Comment: 40 pages, 17 figures available on request. RevTeX version 2.

Compensatory density feedback of Oncomelania hupensis populations in two different environmental settings in China

BACKGROUND: The most recent strategy for schistosomiasis control in the People's Republic of China aims to reduce the likelihood of environmental contamination of schistosome eggs. Despite considerable progress, it is believed that achievements would be further consolidated with additional intermediate host snail control measures. We provide an empirical framework for discerning the relative contribution of intrinsic effects (density feedback) from other extrinsic drivers of snail population dynamics. METHODS: We set up experiments in two study locations to collect reproduction data of Oncomelania hupensis, the intermediate host snail of Schistosoma japonicum. We applied a set of four population dynamic models that have been widely used to study phenomenological time-series data to examine the properties of demographic density feedback patterns from abundance data. We also contrasted the obtained results with the component feedback of density on survival rate to determine whether adult survival was the principal driver of the demographic feedback observed. RESULTS: Demographic density feedback models (Ricker- and Gompertz-logistic) accounted for <99% of Akaike's information criterion model weight, with the Gompertz ranking highest in all O. hupensis population groups. We found some evidence for stronger compensatory feedback in the O. hupensis population from Sichuan compared to a Jiangsu population. Survival rates revealed strong component feedback, but the log-linear relationships (i.e. Gompertz) had less support in the demographic feedback analysis. CONCLUSIONS: Our findings indicate that integrated schistosomiasis control measures must continue to reduce parasite abundance further because intermediate host snail populations tend to grow exponentially at low densities, especially O. hupensis populations in mountainous regions. We conclude that density feedback in adult survival is the principal component contribution to the demographic phenomenon observed in the population fitness (r)-abundance relationship

Artificial selection for nonreproductive host killing in a native parasitoid on the invasive pest, Drosophila suzukii

Abstract Establishment and spread of invasive species can be facilitated by lack of natural enemies in the invaded area. Host‐range evolution of natural enemies augments their ability to reduce the impact of the invader and could enhance their value for biological control. We assessed the potential of the Drosophila parasitoid, Leptopilina heterotoma (Hymenoptera: Figitidae), to exploit the invasive pest Drosophila suzukii by focusing on three performance indices: (i) attack rate; (ii) host killing, consisting of killing rate and lethal attack rate (killing efficiency); and (iii) successful offspring development (reproductive success). We found significant intraspecific variation in attack rate and killing rate and lethal attack rate among seven European populations, but offspring generally failed to successfully develop from the D. suzukii host. We crossed these European lines to create a genetically variable source population and performed a half‐sib analysis to quantify genetic variation. Using a Bayesian animal model, we found that attack rate and killing rate had a heritability of h2=0.2, lethal attack rate h2=0.4, and offspring development h2=0. We then artificially selected wasps with the highest killing rate of D. suzukii for seven generations to test whether host‐killing could be improved. There was a small and inconsistent response to selection in the three selection lines. Realized heritability (hr2) after four generations of selection was 0.17 but near zero after seven generations of selection. The genetic response might have been masked by an increased D. suzukii fitness resulting from adaptation to laboratory conditions. Our study reveals that native, European, L. heterotoma can attack the invasive pest, D. suzukii and significantly reduce fly survival and that different steps of the parasitization process need to be considered in the evolution of host‐range. It highlights how evolutionary principles can be applied to optimize performance of native species for biological control

Periodic travelling waves in cyclic populations: field studies and reaction–diffusion models

Periodic travelling waves have been reported in a number of recent spatio-temporal field studies of populations undergoing multi-year cycles. Mathematical modelling has a major role to play in understanding these results and informing future empirical studies. We review the relevant field data and summarize the statistical methods used to detect periodic waves. We then discuss the mathematical theory of periodic travelling waves in oscillatory reaction–diffusion equations. We describe the notion of a wave family, and various ecologically relevant scenarios in which periodic travelling waves occur. We also discuss wave stability, including recent computational developments. Although we focus on oscillatory reaction–diffusion equations, a brief discussion of other types of model in which periodic travelling waves have been demonstrated is also included. We end by proposing 10 research challenges in this area, five mathematical and five empirical