6,395 research outputs found
Correlations between pressure and bandwidth effects in metal-insulator transitions in manganites
The effect of pressure on the metal-insulator transition in manganites with a
broad range of bandwidths is investigated. A critical pressure is found at
which the metal-insulator transition temperature, T, reaches a maximum
value in every sample studied. The origin of this universal pressure and the
relation between the pressure effect and the bandwidth on the metal-insulator
transition are discussed
Measurement of the Mass Profile of Abell 1689
In this letter we present calibrated mass and light profiles of the rich
cluster of galaxies Abell 1689 out to 1 Mpc from the center. The high
surface density of faint blue galaxies at high redshift, selected by their low
surface brightness, are unique tools for mapping the projected mass
distribution of foreground mass concentrations. The systematic gravitational
lens distortions of of these background galaxies in 15\arcmin\ fields
reveal detailed mass profiles for intervening clusters of galaxies, and are a
direct measure of the growth of mass inhomogeneity. The mass is measured
directly, avoiding uncertainties encountered in velocity or X-ray derived mass
estimates.
Mass in the rich cluster Abell 1689 follows smoothed light, outside 100
h kpc, with a rest-frame V band mass-to-light ratio of
. Near the cluster center, mass appears to be more
smoothly distributed than light. Out to a radius of 1 Mpc the total
mass follows a steeper than isothermal profile. Comparing with preliminary high
resolution N-body clustering simulations for various cosmogonies on these
scales, these data are incompatible with hot dark matter, a poor fit to most
mixed dark matter models, and favor open or cold dark matter.
Substructure is seen in both the mass and the light, but detailed
correspondence is erased on scales less than 100 kpc.Comment: 13 pages, uuencoded, compressed postscript file, 2 figures included
additional 1Mbyte figure available on request. Only change is that in
original errorbars on Fig. 5 were a factor of 2 too big
Pressure Induced Reentrant Electronic and Magnetic State in Pr0.7Ca0.3MnO3 Manganite
In PrCaMnO, pressure induces reentrant magnetic and
electronic state changes in the range 1 atm to 6 GPa. The
metal-insulator and magnetic transition temperatures coincide from 1 to 5
GPa, decouple outside of this range and do not change monotonically with
pressure. The effects may be explained by pressure tuned competition between
double exchange and super exchange. The insulating state induced by pressure
above 5 GPa is possibly ferromagnetic, different from the ferromagnetic
and antiferromagnetic phase-separated insulating state below 0.8 GPa
Blasphemy and Judicial Legitimacy in Indonesia
When contentious blasphemy laws are pressed into service in fledgling democracies with illiberal tendencies such as Indonesia, critical questions arise about judicial integrity and the political nature of blasphemy trials. Judicial legitimacy in Indonesia is defined according to international standards and conventions. The focus is on judicial propriety rather than the popularity or majoritarian appeal of court decisions. In May 2017 a watershed moment occurred in Indonesia as the former governor of Jakarta Basuki Tjahaja Purnama (popularly known as Ahok) was found guilty of desecrating religion and sentenced to 2 years in prison. Judgments rendered in politicized blasphemy trials such as these fail to meet standards of impartiality, and when discursive transgressions of a blasphemous nature occur there are deep ambiguities of meaning and intent. This paper contends that the revival of blasphemy as a punishable crime relates to political power calculations and electoral opportunities, and offers an analysis of blasphemy in Indonesia through the quasi-historical lens of a discursive crime premised on the fallacy that religious offence threatens public order. Blasphemy trials are further complicated by the fact that religious authorities and Islamic mass organizations in Indonesia have significant influence over judicial processes
Spiral Waves in Media with Complex Excitable Dynamics
The structure of spiral waves is investigated in super-excitable
reaction-diffusion systems where the local dynamics exhibits multi-looped phase
space trajectories. It is shown that such systems support stable spiral waves
with broken symmetry and complex temporal dynamics. The main structural
features of such waves, synchronization defect lines, are demonstrated to be
similar to those of spiral waves in systems with complex-oscillatory dynamics.Comment: to appear in International Journal of Bifurcation and Chao
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