When do we feel sorry for others?: an externality of lake use as an example

The purpose of the study was to verify, through the use of an experimental method, the assumption that the ‘economic human’ pays more attention to the externality he/she causes as the strength of externality increases. We used a social-experiment design within an undergraduate classroom to test assumptions, using statistical method. A lakeside plant was used as an example. Our results confirmed the following: (1) 66% of subjects behaved altruistically, while the remainder (34%) behaved selfishly, suggesting that the assumption of mainstream economics may not be appropriate; (2) when we compared situations in which the plots with the natural resource (e.g. the plant) to which the economic human had property rights were large or small in number, those who possessed larger plots tended to be more conservative in resource use; and (3) when we compared situations where the economic human’s extent of influence on natural resources was large or small, those with greater influence tended to be more conservative in resource use. Although mainstream economics assumes a rational economic human—who is supposedly selfish—our results suggest that altruistic behaviour dominates selfish behaviour, and that altruistic behavior should be taken into greater consideration when making policy

Peculiar Behavior of Si Cluster Ions in Solid Al

A peculiar ion behavior is found in a Si cluster, moving with a speed of ~0.22c (c: speed of light) in a solid Al plasma: the Si ion, moving behind the forward moving Si ion closely in a several angstrom distance in the cluster, feels the wake field generated by the forward Si. The interaction potential on the rear Si may balance the deceleration backward force by itself with the acceleration forward force by the forward Si in the longitudinal moving direction. The forward Si would be decelerated normally. However, the deceleration of the rear Si, moving behind closely, would be reduced significantly, and the rear Si may catch up and overtake the forward moving Si in the cluster during the Si cluster interaction with the high-density Al plasma

SPMHD simulations of Structure Formation

The intracluster medium of galaxy clusters is permeated by {\mu}G magnetic fields. Observations with current and future facilities have the potential to illuminate the role of these magnetic fields play in the astrophysical processes of galaxy clusters. To obtain a greater understanding of how the initial seed fields evolve to the magnetic fields in the intracluster medium requires magnetohydrodynamic simulations. We critically assess the current Smoothed Particle Magneto-Hydrodynamics (SPMHD) schemes, especially highlighting the impact of a hyperbolic divergence cleaning scheme and artificial resistivity switch on the magnetic field evolution in cosmological simulations of the formation of a galaxy cluster using the N-body/SPMHD code gcmhd++. The impact and performance of the cleaning scheme and two different schemes for the artificial resistivity switch is demonstrated via idealized test cases and cosmological simulations. We demonstrate that the hyperbolic divergence cleaning scheme is effective at suppressing the growth of the numerical divergence error of the magnetic field and should be applied to any SPMHD simulation. Although the artificial resistivity is important in the strong field regime, it can suppress the growth of the magnetic field in the weak field regime, such as galaxy clusters. With sufficient resolution, simulations with divergence cleaning can reproduce observed magnetic fields. We conclude that the cleaning scheme alone is sufficient for galaxy cluster simulations, but our results indicate that the SPMHD scheme must be carefully chosen depending on the regime of the magnetic field.Comment: 15 pages, 11 figures, published (MNRAS 476 2890