High topography in eastern Tibet is thought to have formed when deep crust beneath the central Tibetan Plateau flowed towards the plateau margin, causing crustal thickening and surface uplift. Rapid exhumation starting about 10-15 million years ago is inferred to mark the onset of surface uplift and fluvial incision. Although geophysical data are consistent with weak crust capable of flow, it is unclear how the timing and amount of deformation adjacent to the Sichuan Basin during the Cenozoic era can be explained in this way. Here we use thermochronology to measure the cooling histories of rocks exposed in a section that stretches vertically over 3 km adjacent to the Sichuan Basin. Our thermal models of exhumation-driven cooling show that these rocks, and hence the plateau margin, were subject to slow, steady exhumation during early Cenozoic time, followed by two pulses of rapid exhumation, one beginning 30-25 million years ago and a second 10-15 million years ago that continues to present. Our findings imply that significant topographic relief existed adjacent to the Sichuan Basin before the Indo-Asian collision. Furthermore, the onset of Cenozoic mountain building probably pre-dated development of the weak lower crust, implying that early topography was instead formed during thickening of the upper crust along faults. We suggest that episodes of mountain building may reflect distinct geodynamic mechanisms of crustal thickening.

It has been a long-lasting debate whether the heart's stroke volume (SV) increases at high aerobic intensities or plateau. Further, sex and level of aerobic power are shown to influence the response. The purpose of this study was to investigate the SV at increasing intensities in elite female athletes and moderately trained females. 13 elite athletes and 11 moderately trained controls with maximal oxygen consumption (VO2max) of 67.1 +/- 6.1 and 49.5 +/- 2.3 mL.min(-1) . kg(-1), respectively, were recruited. SV was measured at rest, and running on a treadmill at 40%, 60%, 80% and 100% of VO2max using the single breath acetylene uptake (SB) technique. Both groups showed a significant (p < 0.05) increase in SV from 40% of VO2max to VO2max, with increases from 105.3 +/- 19.0 to 129.1 +/- 16.3 mL.beat(-1) for the elite females and from 68.7 +/- 21.7 to 82.7 +/- 14.0 mL.beat(-1) for the moderately trained. No diff erences were observed between groups in these increases, but the elite athletes displayed a larger (p < 0.05) SV at all intensities. It is concluded that the SV increases at high aerobic intensities both in elite athlete females and moderately trained females.

GYRO is used to examine the perturbed magnetic field structure generated by electromagnetic gyrokinetic simulations of the CYCLONE base case as beta e is varied from 0.1% to 0.7%, as investigated by J. Candy [Phys. Plasmas 12, 072307 (2005)]. Poincare surface of section plots obtained from integrating the self-consistent magnetic field demonstrates widespread stochasticity for all nonzero values of beta e. Despite widespread stochasticity of the perturbed magnetic fields, no significant increase in electron transport is observed. The magnetic diffusion, d m [A. B. Rechester and M. N. Rosenbluth, Phys. Rev. Lett 40, 38 (1978)], is used to quantify the degree of stochasticity and related to the electron heat transport for hundreds of time slices in each simulation.

Earthquake ruptures on the San Andreas Fault are affected by the material contrast across the fault. Previous observations of microearthquakes at the northern end of the creeping section have found strong signals of asymmetry in both rupture directivity (preferential propagation to the SE), and aftershock asymmetry (many more to the NW, on timescales from 10s to 9 hr). To understand the aftershock asymmetry, Rubin & Ampuero simulated slip-weakening ruptures on a bimaterial interface and observed differences in the timescales for the two edges to experience their peak stress after being slowed by barriers. This is suggestive of the possibility of asymmetry of subevents in compound earthquakes. A second possible source of subevent asymmetry is that when slowed by barriers, a significant tensile stress pulse is predicted to propagate in the SE but not the NW direction. To study the possible asymmetry of subevent distribution, we search for compound events using an empirical Green's function method. Three sections on the northern San Andreas and part of the Calaveras faults were selected where the events have high spatial density and similar focal mechanisms. About 677 candidate compound events were identified in a 28869-event catalogue from 1984 to 2009. Most delays between the two subevents cluster around the shear wave transit time over the subevent separation, although with considerable scatter. For subevents on the San Andreas Fault separated by 0.7-2 times the estimated radius of the first subevent (the same spatial separation found to exhibit strong asymmetry of longer term aftershocks), nearly twice as many second subevents occurred to the SE of the first than to the NW. This asymmetry of second subevent distribution is not present on the Calaveras Fault, which does not have a significant across-fault contrast in wave speed in this region. One interpretation is that the extra SE subevents on the San Andreas Fault are representative of the events `missing'from the `longer term'(10s-9 hr) aftershock population because they became part of the main shock.