Chaos in a Two-Dimensional Ising Spin Glass

We study chaos in a two dimensional Ising spin glass by finite temperature Monte Carlo simulations. We are able to detect chaos with respect to temperature changes as well as chaos with respect to changing the bonds, and find that the chaos exponents for these two cases are equal. Our value for the exponent appears to be consistent with that obtained in studies at zero temperature.Comment: 4 pages, LaTeX, 4 postscript figures included. The analysis of the data is now done somewhat differently. The results are consistent with the chaos exponent found at zero temperature. Additional papers of PY can be obtained on-line at http://schubert.ucsc.edu/pete

Rocking isolation of a typical bridge pier on spread foundation

It has been observed that after some earthquakes a number of structures resting on spread footings responded to seismic excitation by rocking on their foundation and in some cases this enabled them to avoid failure. Through application to a standard bridge supported by direct foundations, this paper discusses the major differences in response when foundation uplift is taken into consideration. Special focus is given on the modifications of rocking response under biaxial and tri-axial excitation with respect to uniaxial excitation. It is found that inelastic rocking has a significant isolation effect. It is also shown that this effect increases under biaxial excitation while it is less sensitive to the vertical component of the earthquake. Finally, parametric analyses show that the isolation effect of foundation rocking increases as the size of the footing and the yield strength of the underlying soil decreases

Universality and universal finite-size scaling functions in four-dimensional Ising spin glasses

We study the four-dimensional Ising spin glass with Gaussian and bond-diluted bimodal distributed interactions via large-scale Monte Carlo simulations and show via an extensive finite-size scaling analysis that four-dimensional Ising spin glasses obey universality.Comment: 12 pages, 9 figures, 4 table

Global processes of anthropogenesis characterise the early Anthropocene in the Japanese Islands

Although many scholars date the onset of the Anthropocene to the Industrial Revolution or the post-1945 ‘Great Acceleration’, there is growing interest in understanding earlier human impacts on the earth system. Research on the ‘Palaeoanthropocene’ has investigated the role of fire, agriculture, trade, urbanisation and other anthropogenic impacts. While there is increasing consensus that such impacts were more important than previously realised, geographical variation during the Palaeoanthropocene remains poorly understood. Here, we present a preliminary comparative analysis of claims that pre-industrial anthropogenic impacts in Japan were significantly reduced by four factors: the late arrival of agriculture, an emphasis on wet-rice farming limited to alluvial plains, a reliance on seafood rather than domesticated animals as a primary source of dietary protein, and cultural ideologies of environmental stewardship. We find that none of these claims of Japanese exceptionalism can be supported by the archaeological and historical records. We make some suggestions for further research but conclude that the Japanese sequence appears consistent with global trends towards increased anthropogenic impacts over the course of the Palaeoanthropocene.Introduction Claims for Japanese environmental exceptionalism - Claim 1: late arrival of agriculture. - Claim 2: the sustainability of rice. - Claim 3: domesticated animals versus marine foods. - Claim 4: cultural ideologies of stewardship. Conclusion

Evidences Against Temperature Chaos in Mean Field and Realistic Spin Glasses

We discuss temperature chaos in mean field and realistic 3D spin glasses. Our numerical simulations show no trace of a temperature chaotic behavior for the system sizes considered. We discuss the experimental and theoretical implications of these findings.Comment: 4 pages in aps format. 6 .ps figures. It is better to print the paper in colou

Aluminium oxide in the atmosphere of hot Jupiter WASP-43bv

We have conducted a re-analysis of publicly available Hubble Space Telescope Wide Field Camera 3 (HST WFC3) transmission data for the hot-Jupiter exoplanet WASP-43b, using the Bayesian retrieval package Tau-REx. We report evidence of AlO in transmission to a high level of statistical significance (>5σ in comparison to a flat model, and 3.4σ in comparison to a model with H2O only). We find no evidence of the presence of CO, CO2, or CH4 based on the available HST WFC3 data or on Spitzer IRAC data. We demonstrate that AlO is the molecule that fits the data to the highest level of confidence out of all molecules for which high-temperature opacity data currently exists in the infrared region covered by the HST WFC3 instrument, and that the subsequent inclusion of Spitzer IRAC data points in our retrieval further supports the presence of AlO. H2O is the only other molecule we find to be statistically significant in this region. AlO is not expected from the equilibrium chemistry at the temperatures and pressures of the atmospheric layer that is being probed by the observed data. Its presence therefore implies direct evidence of some disequilibrium processes with links to atmospheric dynamics. Implications for future study using instruments such as the James Webb Space Telescope are discussed, along with future opacity needs. Comparisons are made with previous studies into WASP-43b

Two component butterfly hysteresis in Ru1222 ruthenocuprate

We report detailed studies of the ac susceptibility butterfly hysteresis on the Ru1222 ruthenocuprate compounds. Two separate contributions to these hysteresis have been identified and studied. One contribution is ferromagnetic-like and is characterized by the coercive field maximum. Another contribution, represented by the so called inverted maximum, is related to the unusual inverted loops, unique feature of Ru1222 butterfly hysteresis. The different nature of the two identified magnetic contributions is proved by the different temperature dependences involved. By lowering the temperature the inverted peak gradually disappears while the coercive field slowly raises. If the maximum dc field for the hysteresis is increased, the size of the inverted part of the butterfly hysteresis monotonously grows while the position of the peak saturates. In reaching saturation exponential field dependence has been demonstrated to take place. At T = 78 K the saturation field is 42 Oe.Comment: 5 pages, 5 figure