Tracking of magnetic flux concentrations over a five-day observation and an insight into surface magnetic flux transport

The solar dynamo problem is the question of how the cyclic variation in the solar magnetic field is maintained. One of the important processes is the transport of magnetic flux by surface convection. To reveal this process, the dependence of the squared displacement of magnetic flux concentrations upon the elapsed time is investigated in this paper via a feature-recognition technique and a continual five-day magnetogram. This represents the longest time scale over which a satellite observation has ever been performed for this problem. The dependence is found to follow a power-law and differ significantly from that of diffusion transport. Furthermore there is a change in the behavior at a spatial scale of 10^{3.8} km. A super-diffusion behavior with an index of 1.4 is found on smaller scales, while changing to a sub-diffusion behavior with an index of 0.6 on larger ones. I interpret this difference in the transport regime as coming from the network-flow pattern.Comment: 18 pages, 9 figures, accepted for publication in the Journal of Space Weather and Space Climate (SWSC

Computational procedure for finite difference solution of one-dimensional heat conduction problems reduces computer time

Computational procedure reduces the numerical effort whenever the method of finite differences is used to solve ablation problems for which the surface recession is large relative to the initial slab thickness. The number of numerical operations required for a given maximum space mesh size is reduced

Working while enrolled in a university: Does it pay?

Working while studying at university increases the time-to-degree and may interfere with learning, but the acquired work experience may also improve employment opportunities and increase wages after the graduation. This study examines how university students' employment decisions affect their labor market success after the graduation. The study is based on an individual panel data set of Finnish university students. The data set covers the years 1987-1998, which was a period of significant changes in the Finnish labor market. The study finds that in-school work experience increases graduates' earnings at the beginning of the career, but there are no statistically significant persistent effects on employment or earnings after controlling for the selection bias in work experience acquisition.university; in-school work; earnings

Symmetry energy, unstable nuclei, and neutron star crusts

Phenomenological approach to inhomogeneous nuclear matter is useful to describe fundamental properties of atomic nuclei and neutron star crusts in terms of the equation of state of uniform nuclear matter. We review a series of researches that we have developed by following this approach. We start with more than 200 equations of state that are consistent with empirical masses and charge radii of stable nuclei and then apply them to describe matter radii and masses of unstable nuclei, proton elastic scattering and total reaction cross sections off unstable nuclei, and nuclei in neutron star crusts including nuclear pasta. We finally discuss the possibility of constraining the density dependence of the symmetry energy from experiments on unstable nuclei and even observations of quasi-periodic oscillations in giant flares of soft gamma-ray repeaters.Comment: 17 pages, 16 figures, to appear in EPJA special volume on symmetry energy. arXiv admin note: text overlap with arXiv:1303.450

Network and psychological effects in urban movement

Correlations are regularly found in space syntax studies between graph-based configurational measures of street networks, represented as lines, and observed movement patterns. This suggests that topological and geometric complexity are critically involved in how people navigate urban grids. This has caused difficulties with orthodox urban modelling, since it has always been assumed that insofar as spatial factors play a role in navigation, it will be on the basis of metric distance. In spite of much experimental evidence from cognitive science that geometric and topological factors are involved in navigation, and that metric distance is unlikely to be the best criterion for navigational choices, the matter has not been convincingly resolved since no method has existed for extracting cognitive information from aggregate flows. Within the space syntax literature it has also remained unclear how far the correlations that are found with syntactic variables at the level of aggregate flows are due to cognitive factors operating at the level of individual movers, or they are simply mathematically probable network effects, that is emergent statistical effects from the structure of line networks, independent of the psychology of navigational choices. Here we suggest how both problems can be resolved, by showing three things: first, how cognitive inferences can be made from aggregate urban flow data and distinguished from network effects; second by showing that urban movement, both vehicular and pedestrian, are shaped far more by the geometrical and topological properties of the grid than by its metric properties; and third by demonstrating that the influence of these factors on movement is a cognitive, not network, effect

A Heuristic Method of Generating Diameter 3 Graphs for Order/Degree Problem

We propose a heuristic method that generates a graph for order/degree problem. Target graphs of our heuristics have large order (> 4000) and diameter 3. We describe the ob- servation of smaller graphs and basic structure of our heuristics. We also explain an evaluation function of each edge for efficient 2-opt local search. Using them, we found the best solutions for several graphs.Comment: Proceedings of 10th IEEE/ACM International Symposium on Networks-on-Chip, Nara, Japan, Aug. 201