We present the X-ray timing results of the new black hole candidate (BHC) MAXI J1535-571 during its 2017 outburst from Hard X-ray Modulation Telescope (Insight -HXMT) observations taken from 2017 September 6 to 23. Following the definitions given by Belloni (2010), we find that the source exhibits state transitions from Low/Hard state (LHS) to Hard Intermediate state (HIMS) and eventually to Soft Intermediate state (SIMS). Quasi-periodic oscillations (QPOs) are found in the intermediate states, which suggest different types of QPOs. With the large effective area of Insight -HXMT at high energies, we are able to present the energy dependence of the QPO amplitude and centroid frequency up to 100 keV which is rarely explored by previous satellites. We also find that the phase lag at the type-C QPOs centroid frequency is negative (soft lags) and strongly correlated with the centroid frequency. By assuming a geometrical origin of type-C QPOs, the source is consistent with being a high inclination system.

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Some studies on the relationship between soil erosion and subsequent redeposition of eroded soils in the same field and soil quality have been conducted in croplands, yet few studies have revealed this relationship in rangelands. We selected a toposequence with a slope of 30% and a horizontal length of 342 m from the rangeland in the northern Tibet Autonomous Region, China (31 16 0 N, 92 09 0 E) to determine the relationship between soil erosion, soil organic carbon (SOC) content and available P patterns within a hillslope landscape. Soil samples for the determination of 137 Cs as well as SOC, available P and particle-size fractions were collected at 20 m intervals along a transect of this hillslope. Soil redistribution was caused primarily by wind erosion at toe-slope positions, but primarily by water erosion at the hillslope positions above the toe-slope. In upper-and mid-slope portions (0 m to 244 m horizontal length), SOC content is closely correlated to 137 Cs concentration (r ¼ 0.74, P < 0.01, n ¼ 15), suggesting that SOC distribution along the slope was similar to 137 Cs distribution, which itself was dependent on topographic changes. However, SOC contents in toe-slope portions are less than those above the toe-slope (i.e. upper-and mid-slope portions), and the correlation between 137 Cs and SOC in the toe-slope portion is weaker than that above the toe-slope. A highly significant correlation (r ¼ 0.72, P < 0.001, n ¼ 20) between 137 Cs concentration and available P was found within the whole hillslope landscape, implying the distribution pattern of available P was somewhat different from that of SOC. We suggest that the distribution of SOC within the hillslope landscape is also affected by factors such as assimilation rates due to difference in grassland productivity at different points and different biological oxidation rates of carbon related to patterns of moisture distribution.

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