Interplay between structure and magnetism in Mo12S9I9Mo_{12} S_9 I_9 nanowires

We investigate the equilibrium geometry and electronic structure of Mo$_{12}$S$_{9}$I$_{9}$ nanowires using ab initio Density Functional calculations. The skeleton of these unusually stable nanowires consists of rigid, functionalized Mo octahedra, connected by flexible, bi-stable sulphur bridges. This structural flexibility translates into a capability to stretch up to approximate 20% at almost no energy cost. The nanowires change from conductors to narrow-gap magnetic semiconductors in one of their structural isomers.Comment: 4 pages with PRL standards and 3 figure

Lattice simulations of real-time quantum fields

We investigate lattice simulations of scalar and nonabelian gauge fields in Minkowski space-time. For SU(2) gauge-theory expectation values of link variables in 3+1 dimensions are constructed by a stochastic process in an additional (5th) ``Langevin-time''. A sufficiently small Langevin step size and the use of a tilted real-time contour leads to converging results in general. All fixed point solutions are shown to fulfil the infinite hierarchy of Dyson-Schwinger identities, however, they are not unique without further constraints. For the nonabelian gauge theory the thermal equilibrium fixed point is only approached at intermediate Langevin-times. It becomes more stable if the complex time path is deformed towards Euclidean space-time. We analyze this behavior further using the real-time evolution of a quantum anharmonic oscillator, which is alternatively solved by diagonalizing its Hamiltonian. Without further optimization stochastic quantization can give accurate descriptions if the real-time extend of the lattice is small on the scale of the inverse temperature.Comment: 36 pages, 15 figures, Late

Simulating nonequilibrium quantum fields with stochastic quantization techniques

We present lattice simulations of nonequilibrium quantum fields in Minkowskian space-time. Starting from a non-thermal initial state, the real-time quantum ensemble in 3+1 dimensions is constructed by a stochastic process in an additional (5th) ``Langevin-time''. For the example of a self-interacting scalar field we show how to resolve apparent unstable Langevin dynamics, and compare our quantum results with those obtained in classical field theory. Such a direct simulation method is crucial for our understanding of collision experiments of heavy nuclei or other nonequilibrium phenomena in strongly coupled quantum many-body systems.Comment: 4 pages, 4 figures, PRL version, minor change

Complex Langevin Equation and the Many-Fermion Problem

We study the utility of a complex Langevin (CL) equation as an alternative for the Monte Carlo (MC) procedure in the evaluation of expectation values occurring in fermionic many-body problems. We find that a CL approach is natural in cases where non-positive definite probability measures occur, and remains accurate even when the corresponding MC calculation develops a severe ``sign problem''. While the convergence of CL averages cannot be guaranteed in principle, we show how convergent results can be obtained in three examples ranging from simple one-dimensional integrals over quantum mechanical models to a schematic shell model path integral.Comment: 19 pages, 10 PS figures embedded in tex

Development and characterization of osteogenic cell sheets in an in vivo model

[Excerpt] Despite some successes in the tissue engineering field its evolution seems to be tampered by limitations such as cell sourcing and the lack of adequate scaffolds to support cell growth and differentiation. The use of stem cells combined with cell sheet engineering technology seems a promising way to overcome these limitations. In this work bone marrow cells were flushed from 3 weeks old Wistar rat femurs and cultured in basal DMEM medium until subconfluence. Cells were then transferred to thermo-responsive dishes (3 x10⁵ cells/dish) and cultured for 3 weeks in osteogenic medium. [...]info:eu-repo/semantics/publishedVersio

Surgical anatomy of the sural nerve for peripheral nerve reconstruction research in swine

The use of peripheral nerves as donor nerves for peripheral nerve regeneration studies, which can provide a long peripheral nerve with intact physiological functions, for autologous nerve grafts was unknown in swine. This study investigated the surgical anatomy of sural nerves (nervus suralis) of cadavers and anesthetized miniature pigs. A loose-S shape incision line was made from the border of the biceps femoris muscle (musculus biceps femoris) to 2 cm above the calx in the leg of anesthetized miniature pigs. The sural nerve was found to branch from the sciatic nerve (nervus ischiadicus) under the biceps femoris muscle and run along the small saphenous vein (vena saphena parva). After being isolated and stimulated using a nerve stimulator, the sural nerve innervated no muscles and tissues in the leg. The sural nerve (14.

Southward propagating auroral structure in meso-micro scale obtained from ground-based multiple observations at Poker Flat Research Range

第3回極域科学シンポジウム/第36回極域宙空圏シンポジウム 11月26日（月）、27日（火） 国立極地研究所 2階ラウン

Generalized Dynamic Scaling for Critical Magnetic Systems

The short-time behaviour of the critical dynamics for magnetic systems is investigated with Monte Carlo methods. Without losing the generality, we consider the relaxation process for the two dimensional Ising and Potts model starting from an initial state with very high temperature and arbitrary magnetization. We confirm the generalized scaling form and observe that the critical characteristic functions of the initial magnetization for the Ising and the Potts model are quite different.Comment: 32 pages with15 eps-figure