Livestock Husbandry between Ethics and Economics: Finding a Feasible Way Out by Target Costing?

Livestock husbandry is a major line of conflict in many industrialized countries. Farmers are caught in a dilemma between ethical considerations imposed by, for instance, nongovernmental organizations and the wider public on the one hand and competitive and economic pressures on the other. In this paper we use a target-costing approach to determine whether it is possible to implement more animal-friendly husbandry conditions for turkey fattening in Germany without sacrificing competitiveness. Empirical results show that, at first glance, the willingness on the part of consumers to pay for more animal welfare exceeds the costs to farmers of more animal-friendly husbandry systems. A critical discussion reveals that this result may be flawed by methodological problems for which no solutions have yet been found.animal welfare, livestock husbandry, target costing, willingness to pay, Livestock Production/Industries, D12, D63, Q12,

Nicht zu vergessende Moleküle ... : flexibles "Networking" von Nervenzellen formt das Gedächtnis

Ein funktionierendes Gedächtnis beruht darauf, dass die Kontakte zwischen den Milliarden Nervenzellen in unserem Gehirn sich ständig verändern und anpassen. Häufig verwendete Signalwege werden verstärkt und ausgebaut, wie eine Landstraße zu einer Schnellstraße. Weniger häufig benutze Signalwege können dagegen abgebaut werden. Die Signalübertragung verlangsamt sich wie der Verkehr auf einer lange nicht mehr instand gehaltenen Straße. Will man diese Prozesse auf molekularer Ebene verstehen, muss man die Synapsen näher betrachten. Das sind spezialisierte Kontaktstellen, die es den Nervenzellen ermöglichen, hochkomplexe Netzwerke, sogenannte Schaltkreise, zu knüpfen. Die Flexibilität dieser Schaltkreise ermöglicht es uns, Informationen zu verarbeiten und entsprechend zu reagieren. Inzwischen kennt man eine Fülle von Boten-Molekülen, Rezeptoren und Liganden, die diese Prozesse auf molekularer Ebene steuern

Crossover from hc/e to hc/2e current oscillations in rings of s-wave superconductors

We analyze the crossover from an hc/e-periodicity of the persistent current in flux threaded clean metallic rings towards an hc/2e-flux periodicity of the supercurrent upon entering the superconducting state. On the basis of a model calculation for a one-dimensional ring we identify the underlying mechanism, which balances the hc/e versus the hc/2e periodic components of the current density. When the ring circumference exceeds the coherence length of the superconductor, the flux dependence is strictly hc/2e periodic. Further, we develop a multi-channel model which reduces the Bogoliubov - de Gennes equations to a one-dimensional differential equation for the radial component of the wave function. The discretization of this differential equation introduces transverse channels, whose number scales with the thickness of the ring. The periodicity crossover is analyzed close the critical temperature

Growth of a vortex polycrystal in type II superconductors

We discuss the formation of a vortex polycrystal in type II superconductors from the competition between pinning and elastic forces. We compute the elastic energy of a deformed grain boundary, that is strongly non-local, and obtain the depinning stress for weak and strong pinning. Our estimates for the grain size dependence on the magnetic field strength are in good agreement with previous experiments on NbMo. Finally, we discuss the effect of thermal noise on grain growth.Comment: 4 pages, 2 figure

Expertise and Trust-Aware Social Web Service Recommendation

With the increasing number of Web services, the personalized recommendation of Web services has become more and more important. Fortunately, the social network popularity nowadays brings a good alternative for social recommendation to avoid the data sparsity problem that is not treated very well in the collaborative filtering approach. Since the social network provides a big data about the users, the trust concept has become necessary to filter this abundance and to foster the successful interactions between the users. In this paper, we firstly propose a trusted friend detection mechanism in a social network. The dynamic of the users’ interactions over time and the similarity of their interests have been considered. Secondly, we propose a Web service social recommendation mechanism which considers the expertise of the trusted friends according to their past invocation histories and the active user’s query. The experiments of each mechanism produced satisfactory results

Modelling molecule-surface interactions-an automated quantum-classical approach using a genetic algorithm

We present an automated and efficient method to develop force fields for molecule-surface interactions. A genetic algorithm (GA) is used to parameterise a classical force field so that the classical adsorption energy landscape of a molecule on a surface matches the corresponding landscape from density functional theory (DFT) calculations. The procedure performs a sophisticated search in the parameter phase space and converges very quickly. The method is capable of fitting a significant number of structures and corresponding adsorption energies. Water on a ZnO(0001) surface was chosen as a benchmark system but the method is implemented in a flexible way and can be applied to any system of interest. In the present case, pairwise Lennard Jones (LJ) and Coulomb potentials are used to describe the molecule-surface interactions. In the course of the fitting procedure, the LJ parameters are refined in order to reproduce the adsorption energy landscape. The classical model is capable of describing a wide range of energies, which is essential for a realistic description of a fluid-solid interface

Tackling Exascale Software Challenges in Molecular Dynamics Simulations with GROMACS

GROMACS is a widely used package for biomolecular simulation, and over the last two decades it has evolved from small-scale efficiency to advanced heterogeneous acceleration and multi-level parallelism targeting some of the largest supercomputers in the world. Here, we describe some of the ways we have been able to realize this through the use of parallelization on all levels, combined with a constant focus on absolute performance. Release 4.6 of GROMACS uses SIMD acceleration on a wide range of architectures, GPU offloading acceleration, and both OpenMP and MPI parallelism within and between nodes, respectively. The recent work on acceleration made it necessary to revisit the fundamental algorithms of molecular simulation, including the concept of neighborsearching, and we discuss the present and future challenges we see for exascale simulation - in particular a very fine-grained task parallelism. We also discuss the software management, code peer review and continuous integration testing required for a project of this complexity.Comment: EASC 2014 conference proceedin

Electron-beam-induced shift in the apparent position of a pinned vortex in a thin superconducting film

When an electron beam strikes a superconducting thin film near a pinned vortex, it locally increases the temperature-dependent London penetration depth and perturbs the circulating supercurrent, thereby distorting the vortex's magnetic field toward the heated spot. This phenomenon has been used to visualize vortices pinned in SQUIDs using low-temperature scanning electron microscopy. In this paper I develop a quantitative theory to calculate the displacement of the vortex-generated magnetic-flux distribution as a function of the distance of the beam spot from the vortex core. The results are calculated using four different models for the spatial distribution of the thermal power deposited by the electron beam.Comment: 9 pages, 6 figures, resubmitted to PRB with referee-suggested revisions, includes new paragraph on numerical evaluatio

Investigating Interactions of Biomembranes and Alcohols: A Multiscale Approach

We study the interaction of lipid bilayers with short chain alcohols using molecular dynamics on different length scales. We use detailed atomistic modeling and modeling on the length scale where an alcohol is just an amphiphilic dimer. Our strategy is to calibrate a coarse--grained model against the detailed model at selected state points at low alcohol concentration and then perform a wider range of simulations using the coarse--grained model. We get semiquantitative agreement with experiment for the major observables such as order parameter and area per molecule. We find a linear increase of area per molecule with alcohol concentration. The alcohol molecules in both system descriptions are in close contact with the glycerol backbone. Butanol molecules can enter the bilayer to some extent in contrast to the behavior of shorter alcohols. At very high alcohol concentrations we find clearly increased interdigitation between leaflets.Comment: 14 pages, 6 figure

Local Simulation Algorithms for Coulombic Interactions

We consider dynamically constrained Monte-Carlo dynamics and show that this leads to the generation of long ranged effective interactions. This allows us to construct a local algorithm for the simulation of charged systems without ever having to evaluate pair potentials or solve the Poisson equation. We discuss a simple implementation of a charged lattice gas as well as more elaborate off-lattice versions of the algorithm. There are analogies between our formulation of electrostatics and the bosonic Hubbard model in the phase approximation. Cluster methods developed for this model further improve the efficiency of the electrostatics algorithm.Comment: Proceedings Statphys22 10 page