The Exact Solution of the Anti-ferromagnetic Ising Model with Multisite Interaction on the Simplest Pure Husimi Lattice

We investigate the anti-ferromagnetic spin- $1/2$ Ising model with the presence of the multisite interaction on the pure Husimi lattice with three sites in the elementary polygon ( $p=3$ ) and coordination number $z=4$ . It represents the simplest approximation of the corresponding anti-ferromagnetic Ising model on the two-dimensional Kagome lattice which takes into account effects of frustration. The exact analytical solution of the model is found and discussed. It is shown that, regardless of the strength of the multisite interaction, the model does not exhibit any kind of the phase transitions. The behavior and properties of the magnetization as the function of the parameter which controls the strength of the multisite interaction and as the function of the external magnetic field are studied in detail. The existence of the magnetization plateaus for low temperatures is shown. In addition, all possible ground states of the model are found and their properties are discussed.     

Trimodal imaging system capable of quantitative phase imaging without 2 pi ambiguities

A neoteric approach to interferometric phase imaging unencumbered by 2 pi phase ambiguities is presented. This technique utilizes an actively controlled angular displacement glass plate positioned in the reference arm of an environmentally stabilized pseudoheterodyne Mach-Zehnder interferometer. The plate is continually adjusted to maintain a constant interferometric output phase, as a phase object in the sample arm is raster scanned. Using a 632.8 nm source, unwrapped phase images of translucent samples ranging from approximately 150 nm to 1.5 microm thick were obtained. This system is incorporated into a conventional near-field scanning optical microscope, which permits simultaneous phase, intensity, and surface morphology studies.     

The Paradox of Time in Dynamic Causal Systems

Recent work has shown that people use temporal information including order, delay, and variability to infer causality between events. In this study, we build on this work by investigating the role of time in dynamic systems, where causes take continuous values and also continually influence their effects. Recent studies of learning in these systems explored short interactions in a setting with rapidly evolving dynamics and modeled people as relying on simpler, resource-limited strategies to grapple with the stream of information. A natural question that arises from such an account is whether interacting with systems that unfold more slowly might reduce the systematic errors that result from these strategies. Paradoxically, we find that slowing the task indeed reduced the frequency of one type of error, albeit at the cost of increasing the overall error rate. To explain these results we posit that human learners analyze continuous dynamics into discrete events and use the observed relationships between events to draw conclusions about causal structure. We formalize this intuition in terms of a novel Causal Event Abstraction model and show that this model indeed captures the observed pattern of errors. We comment on the implications these results have for causal cognition.     

Cationic Geminoid Peptide Amphiphiles Inhibit DENV2 Protease,Furin, and Viral Replication

Dengue is an important arboviral infectious disease for which there is currently no specific cure. We report gemini-like (geminoid) alkylated amphiphilic peptides containing lysines in combination with glycines or alanines (C₁₅H₃₁C(O)-Lys-(Gly or Ala)_nLys-NHC₁₆H₃₃, shorthand notation C₁₆-KX_nK-C₁₆ with X = A or G, and n = 0–2). The representatives with 1 or 2 Ala inhibit dengue protease and human furin, two serine proteases involved in dengue virus infection that have peptides with cationic amino acids as their preferred substrates, with IC₅₀ values in the lower µM range. The geminoid C₁₆-KAK-C₁₆ combined inhibition of DENV2 protease (IC₅₀ 2.3 µM) with efficacy against replication of wildtype DENV2 in LLC-MK2 cells (EC₅₀ 4.1 µM) and an absence of toxicity. We conclude that the lysine-based geminoids have activity against dengue virus infection, which is based on their inhibition of the proteases involved in viral replication and are therefore promising leads to further developing antiviral therapeutics, not limited to dengue.     

Homogenization Approach Based on Laminates

In this work, a homogenization approach for the modeling of the material behavior of two-phase composites motivated by modeling a thin-layer-type microstructure is presented. The basic idea here is to idealize the thin-layered microstructure as a first-order laminate. In particular, a jump in deformation state across the phase interface is modeled constitutively via a rank-one connection of habit-plane type. In the material framework, the value for the jump as well as its direction remain as independent constitutive variables. However, in the case of laminates and an ideal plain interface, the direction is given and stays in a first approach constant. We assume that their values are determined by mechanical and configurational equilibrium in the two-phase composite at the interface. This yields to a set of implicit equations which lead to the corresponding response of the structure. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Local and non‐local ductile damage and failure modelling at large deformation with applications to engineering

The numerical analysis of ductile damage and failure in engineering materials is often based on the micromechanical model of Gurson [1]. Numerical studies in the context of the finite‐element method demonstrate that, as with other such types of local damage models, the numerical simulation of the initiation and propagation of damage zones is strongly mesh‐dependent and thus unreliable. The numerical problems concern the global load‐displacement response as well as the onset, size and orientation of damage zones. From a mathematical point of view, this problem is caused by the loss of ellipticity of the set of partial di.erential equations determining the (rate of) deformation field. One possible way to overcome these problems with and shortcomings of the local modelling is the application of so‐called non‐local damage models. In particular, these are based on the introduction of a gradient type evolution equation of the damage variable regarding the spatial distribution of damage. In this work, we investigate the (material) stability behaviour of local Gurson‐based damage modelling and a gradient‐extension of this modelling at large deformation in order to be able to model the width and other physical aspects of the localization of the damage and failure process in metallic materials.