The Flux-Line Lattice in Superconductors

Magnetic flux can penetrate a type-II superconductor in form of Abrikosov vortices. These tend to arrange in a triangular flux-line lattice (FLL) which is more or less perturbed by material inhomogeneities that pin the flux lines, and in high-$T_c$ supercon- ductors (HTSC's) also by thermal fluctuations. Many properties of the FLL are well described by the phenomenological Ginzburg-Landau theory or by the electromagnetic London theory, which treats the vortex core as a singularity. In Nb alloys and HTSC's the FLL is very soft mainly because of the large magnetic penetration depth: The shear modulus of the FLL is thus small and the tilt modulus is dispersive and becomes very small for short distortion wavelength. This softness of the FLL is enhanced further by the pronounced anisotropy and layered structure of HTSC's, which strongly increases the penetration depth for currents along the c-axis of these uniaxial crystals and may even cause a decoupling of two-dimensional vortex lattices in the Cu-O layers. Thermal fluctuations and softening may melt the FLL and cause thermally activated depinning of the flux lines or of the 2D pancake vortices in the layers. Various phase transitions are predicted for the FLL in layered HTSC's. The linear and nonlinear magnetic response of HTSC's gives rise to interesting effects which strongly depend on the geometry of the experiment.Comment: Review paper for Rep.Prog.Phys., 124 narrow pages. The 30 figures do not exist as postscript file

Determining the anterior-posterior extent of the rat Posterior Parietal Cortex

This paper identifies a location defining the anterior-posterior (AP) boundaries of the posterior parietal cortex (PPC) in the rat brain. The PPC receives information from neuronal connections in various regions of the brain; the regions directly anterior and posterior to the PPC likewise receive information from neurons, but from connections in different brain regions. Two retrograde tracers were injected along the AP axis into sites in and around the PPC. The location of the border between the PPC and neighboring regions can be determined as lying between the two injection sites if the two tracers move to different brain regions as this indicates that the injection sites were not both in the same region, but rather straddle the border. Results are analyzed from a series of repeated experiments in which a pair of injection sites were targeted to straddle the border between PPC and the neighboring region, secondary visual cortex (V2). Improvements to the method used are then addressed to aid future experimentation

An extensible framework for providing dynamic data structure visualizations in a lightweight IDE

A framework for producing dynamic data structure visualizations within the context of a lightweight IDE is described. Multiple synchronized visualizations of a data structure can be created with minimal coding through the use of an external viewer model. The framework supplies a customizable viewer template as well as high-level APIs to a graph drawing library and the Java Debugger Interface. Initial classroom use has demonstrated the framework’s ease of use as well as its potential to as an aid to student learning

Visual Support for Incremental Abstraction and Refinement in Ada 95 - by

GRASP is a software engineering tool which uniquely combines a source code diagramming technique, the control structure diagram (CSD), with other comprehension aids such as complexity visualization, syntax coloring and source code folding. The synergistic combination of these features in GRASP has the potential to be a powerful aid in any activity where source code is expected to be read. The primary focus of GRASP is to improve the comprehension efficiency of software and, as a result, improve reliability and reduce costs during design, implementation, testing, maintenance and reengineering. 1.1 Keywords Software visualization, folding, program understandin