Elastic networks of protein particles

This paper describes the formation and properties of protein particle suspensions. The protein particles were prepared by a versatile method based on quenching a phase-separating protein–polysaccharide mixture. Two proteins were selected, gelatin and whey protein. Gelatin forms aggregates by means of reversible physical bonds, and whey protein forms aggregates that can be stabilized by chemical bonds. Rheology and microscopy show that protein particles aggregate into an elastic particle gel for both proteins. Properties similar to model systems of synthetic colloidal particles were obtained using protein particle suspensions. This suggests that the behaviour of the particle suspensions is mainly governed by the mesoscopic properties of the particle networks and to a lesser extent on the molecular properties of the particle

Towards automated loop-shaping in controller parameter space

This paper presents a data-based control design method for optimal tuning of the parameters of a fixed structure controller with respect to the given closed-loop (CL) performance specifications. The proposed approach is to translate the CL specifications into controller parameter space and to automate the parameter choice through optimization problems. The developed method ensures CL stability and close to optimal controller design for any user defined controller structure, given the frequency response data set of the uncertain plant

Various series expansions for the bilayer S=1/2 Heisenberg antiferromagnet

Various series expansions have been developed for the two-layer, S=1/2, square lattice Heisenberg antiferromagnet. High temperature expansions are used to calculate the temperature dependence of the susceptibility and specific heat. At T=0, Ising expansions are used to study the properties of the N\'{e}el-ordered phase, while dimer expansions are used to calculate the ground-state properties and excitation spectra of the magnetically disordered phase. The antiferromagnetic order-disorder transition point is determined to be $(J_2/J_1)_c=2.537(5)$. Quantities computed include the staggered magnetization, the susceptibility, the triplet spin-wave excitation spectra, the spin-wave velocity, and the spin-wave stiffness. We also estimates that the ratio of the intra- and inter-layer exchange constants to be $J_2/J_1\simeq 0.07$ for cuprate superconductor $YBa_2Cu_3O_{6.2}$.Comment: RevTeX, 9 figure

Model-free norm-based fixed structure controller synthesis

This paper presents a method to perform model-free fixed structure controller synthesis. Based on frequency response data of the plant, the parameters of a predefined controller structure are optimized directly with respect to closed-loop performance specifications. As a result, no parametric plant model is required such that time consuming iterative identification-synthesis procedures can be omitted. A framework is presented to both assure stability and optimize closed-loop performance based on frequency response data. Furthermore, based upon these results, a cost-function is formulated that can be exploited to converge from a destabilizing- to the stabilizing controller parameter region. Both the stability guarantee and performance optimization procedures are combined in one optimization algorithm that is illustrated by means of an example

Density Matrix Renormalisation Group Approach to the Massive Schwinger Model

The massive Schwinger model is studied, using a density matrix renormalisation group approach to the staggered lattice Hamiltonian version of the model. Lattice sizes up to 256 sites are calculated, and the estimates in the continuum limit are almost two orders of magnitude more accurate than previous calculations. Coleman's picture of `half-asymptotic' particles at background field theta = pi is confirmed. The predicted phase transition at finite fermion mass (m/g) is accurately located, and demonstrated to belong in the 2D Ising universality class.Comment: 38 pages, 18 figures, submitted to PR

One strategy doesn’t fit all: determinants of urban adaptation in mammals

Urbanization exposes wildlife to new challenging conditions and environmental pressures. Some mammalian species have adapted to these novel environments, but it remains unclear which characteristics allow them to persist. To address this question we identified 190 mammals regularly recorded in urban settlements worldwide, and used phylogenetic path analysis to test hypotheses regarding which behavioural, ecological, and life history traits favour adaptation to urban environments for different mammalian groups. Our results show that all urban mammals produce larger litters; whereas other traits such as body size, behavioural plasticity and diet diversity were important for some but not all taxonomic groups. This variation highlights the idiosyncrasies of the urban adaptation process and likely reflects the diversity of ecological niches and roles mammals can play. Our study contributes towards a better understanding of mammal association to humans, which will ultimately allow the design of wildlife-friendly urban environments and contribute to mitigate human-wildlife conflicts

Science in Focus: Combining Radiotherapy with Inhibitors of the DNA Damage Response

No abstract available