Earth surface processes and their effects on human behavior in monsoonal China during the Pleistocene-Holocene epochs

There is a wide diversity of landforms in China. The topography of three major ter- races, decreasing in height stepwise from west to east, was formed by the early Miocene. With the commencement of the Great Northern Hemisphere Glaciations （GHGs） and the glacial-interglacial cycles in the Pleistocene, thick loess deposits accumulated in north China, and fluvial terraces were formed and lakes expanded and contracted in eastern and central China. The earliest evidence of hominins in China is dated to ~1.7 Ma; they occupied the monsoon-dominated region for a long interval, until the late Pleistocene, ~50 ka. In this study, we investigated a large area rich in the relics and artifacts of early man. The results indicate that the early humans occupied riverine areas, especially medium-sized fluvial basins, and lake shores. Even in the relatively recent geological past, the occupation and abandonment of settlements were directly forced by the shifting of sand dune fields in the desert-loess transi- tional zone, which in turn was closely associated with variations in the monsoon climate and vegetation patterns. Our observations indicate that landforms were one of the main determi- nants of early human behavior, in that loess tableland, large alluvial plains, desert-Gobi areas, and the Tibetan Plateau, were not suitable environments for early human settlement. We infer that the early humans in China adapted their behavior to specific landforms and landform processes. The monsoon climate, which shapes the large-scale step-like pattern of fluvial landforms, promotes vegetation coverage and dominates soil formation, provides a crucial context for early human adaptation. The adaptation of early humans to earth surface proc- esses in East Asia is investigated for the first time in this study. Future investigations will provide further information that will increase our understanding of the linkage between early human behavior and landform processes in East Asia.

Understanding the Interactions between Climate Change,Landscape Evolution,Surface Processes and Tectonics in the Earth System:What Can the Studies of Chinese Deserts Contribute?

Due to large deserts on Earth surface a thorough understanding of climate change, landscape evolution and geomorphological processes having occurred in deserts is crucial for Earth System Science. The landscapes in deserts are, however, diverse and different over the globe with regard to their geomorphological nature, human activities and geological histories. In the last decades a great number of efforts have been put to the investigation of the initial timing of the occurrence of arid climate, e. g. in northwestern China. Silty sediments in the downwind directions have been used to deduce the histories of deserts. In general, there is a lack of knowledge about processes and landscapes in Chinese drylands between the initial Miocene silt sedimentation at desert margins and the late Quaternary multiple occurrences of wetter climate with assumed large lakes in many of the deserts in northern China. The geomorphological concept of three primary triggering factors, i.e., the sediment supply, sediment availability and transport capacity of wind, and additionally the underground geology need to be fully considered for a better understanding of the environmental histories of sand seas which should not be viewed as equivalent for deserts because sand seas cover between 〈 1% and ca. 45% of the desert areas in various continents dependent on a complex interaction between various processes of both exogenous and endogenous origins.

Pretreatment of Chrysotile With Rare Earth Compounds Lowered Its Cytotoxicity by Lessening Surface Charges

Pathological effects of asbestos are probably dependent on the special surface properties of the fibers, such as surface charge, surface metal ions. The present study was designed to determine whether the pretreatment of chrysotile asbestos fibers (CAF) with rare earth compounds (REC) solution can reduce their pathogenicity. The results showed that REC-pretreated CAF induced less nitrogen oxide (NO) production by alveolar macrophages (AM). In addition, the pretreatment lowered the capacity of hemolysis and the methylene blue (MB) adsorption of the native CAF. These findings suggested that the pretreatment of CAF with REC solution reduced the in vitro toxicity of CAF by lessening its surface charges. Nevertheless, the pathogenicity and the carcinogenicity of REC-pretreated CAF in vivo remain to be investigated.

Evidences of the expanding Earth from space-geodetic data over solid land and sea level rise in recent two decades

According to the space-geodetic data recorded at globally distributed stations over solid land spanning a period of more than 20-years under the International Terrestrial Reference Frame 2008,our previous estimate of the average-weighted vertical variation of the Earth＇s solid surface suggests that the Earth＇s solid part is expanding at a rate of 0.24 ± 0.05 mm/a in recent two decades.In another aspect,the satellite altimetry observations spanning recent two decades demonstrate the sea level rise（SLR） rate 3.2 ± 0.4 mm/a,of which1.8 ± 0.5 mm/a is contributed by the ice melting over land.This study shows that the oceanic thermal expansion is 1.0 ± 0.1 mm/a due to the temperature increase in recent half century,which coincides with the estimate provided by previous authors.The SLR observation by altimetry is not balanced by the ice melting and thermal expansion,which is an open problem before this study.However,in this study we infer that the oceanic part of the Earth is expanding at a rate about 0.4 mm/a.Combining the expansion rates of land part and oceanic part,we conclude that the Earth is expanding at a rate of 0.35 ± 0.47 mm/a in recent two decades.If the Earth expands at this rate,then the altimetry-observed SLR can be well explained.

Comparison of TMI and AMSR-E sea surface temperatures with Argo near-surface temperatures over the global oceans

Satellite-derived sea surface temperatures（SSTs） from the tropical rainfall measuring mission（TRMM）microwave imager（TMI） and the advanced microwave scanning radiometer for the earth observing system（AMSR-E） were compared with non-pumped near-surface temperatures（NSTs） obtained from Argo profiling floats over the global oceans. Factors that might cause temperature differences were examined, including wind speed, columnar water vapor, liquid cloud water, and geographic location. The results show that both TMI and AMSR-E SSTs are highly correlated with the Argo NSTs; however, at low wind speeds, they are on average warmer than the Argo NSTs. The TMI performs slightly better than the AMSR-E at low wind speeds, whereas the TMI SST retrievals might be poorly calibrated at high wind speeds. The temperature differences indicate a warm bias of the TMI/AMSR-E when columnar water vapor is low, which can indicate that neither TMI nor AMSR-E SSTs are well calibrated at high latitudes. The SST in the Kuroshio Extension region has higher variability than in the Kuroshio region. The variability of the temperature difference between the satellite-retrieved SSTs and the Argo NSTs is lower in the Kuroshio Extension during spring. At low wind speeds, neither TMI nor AMSR-E SSTs are well calibrated, although the TMI performs better than the AMSR-E.

A holistic framework for facilitating environmental and human health

In the Anthropocene,health is necessary to achieve global sustainable development.This is a challenge because health issues are complex and span from humans to ecosystems and the environment through dynamic interac-tions across scales.We find that the health issues have been mainly addressed by disciplinary endeavors which unfortunately will not result in panoramic theories or effective solutions.We recommend focusing on the intri-cate interactions between humans,ecosystems and the environment for developing common theoretical under-standings and practical solutions for safeguarding planetary health,with human health as the key indicator and endpoint.To facilitate this paradigm shift,a holistic framework is formulated that incorporates disturbances from inner Earth and our solar system,and accommodates interactions between humans,ecosystems and the environ-ment in a nested hierarchy.An integrative and transdisciplinary health science is advocated along with holistic thinking to resolve our current health challenges and to achieve the health-related sustainable development goals.

Watershed systems science—A new paradigm to understand and govern the impact of human activities on the earth's surface in the Anthropocene

Recent scholars’work in Vol 58 Issue 1(2015)and Cheng and Li’s paper in Vol 58 Issue 7(2015)in Science China Earth Sciences propose development of"Watershed science"by"Bridging new advances in hydrological science with good management of river basins".An analysis of the language and key concepts used in the abstracts,titles and keywords of this set of 8 papers and an editorial reveals that‘Watershed’,‘River’,‘Science’and‘System’are the

Decomposition of the mixed rare earth concentrate by microwave-assisted method

A novel process was proposed to strengthen the decomposition of the mixed rare earth concentrate by utilizing the microwave radiation.Mineralogical information on the mechanisms by which microwave heating improved the leaching behavior of rare earth elements（REEs）,and an interpretation of the interrelationship between mineralogy,decomposition process,and leaching process were provided in this study.The influences of the temperature,time of microwave heating and contents of NaO H（mass ratio of NaO H to mixed rare earth concentrate）on the decomposition of mixed rare earth concentrate were investigated.The results revealed that the temperature was the main factor affecting the decomposition process.The recovery of REEs by hydrochloric acid leaching reached 93.28% under the microwave heating conditions：140 oC,30 min and 35.35% NaO H.The BET specific surface area and SEM analysis indicated that the particles of mixed rare earth concentrate were non-hole,while the particles presented a porous structure after heating the concentrate by microwave radiation.For the microwave treated sample after water leaching,the BET specific surface area was 11.04 m^2/g,which was higher than the corresponding values（6.94 m^2/g）for the mixed rare earth concentrate.This result could be attributed to the phase changes of bastnaesite and monazite,and a number of cracks induced by thermal stress.The increase of BET specific surface area resulted in an increase of the recovery of REEs by promoting interaction within the system of acid leaching.

Surface modification of (Tb,Dy)Fe_2 alloy by nitrogen ion implantation

Effects of nitriding modification on surface phase structure, morphology, corrosion resistance and magnetostriction of （Tb,Dy）Fe2 alloy were investigated by nitrogen ion implantation. Results showed that the surface REFe2 phase gradually decomposed and transformed into REN, α-Fe and Fe8N phases with the increase of nitrogen ion implantation dose. The surface morphology of the alloy had an obvious change after nitrogen ion implantation. The corrosion resistance properties of the alloy in acidic, alkaline and chloridion environment were also greatly improved. In addition, the magnetostriction performance of the alloy was almost not affected by ion implantation as the nitrided layer was quite thin and the operating temperature was very low. The results proved that nitrogen ion implantation was an effective method for surface modification of （Tb,Dy）Fe2 alloy.

Surface characteristics of Y3Al5O12：Ce^3＋ phosphor with greatly enhanced photoluminescence after chemical defect-selective etching

The surface of a commercial Y3Al5O12：Ce^3＋ phosphor was modified by 99% NH_4F＋CH_3COOH solution in a supersonic bath with water temperature of 80 oC for 4 h. The scanning electron microscopy（SEM） results showed that the edge angles were not as sharp as the unmodified particles and the flat surfaces turned rough with many micro-structures covered. Positron lifetime measurements quantitatively showed that surface defects were removed away by more than 50%. As a result, the photoluminescence determinations showed that the backscatter loss was reduced by 4.2% and the emission power was enhanced by 5.6% after the surface modification. The conversion efficiency was greatly improved from 47.3% to 51.1%, as presented by the fluorescence images. Therefore, it would be greatly helpful for the improvement of efficiency, transparency and stability of pc-LED. Moreover, this method was significantly suitable for mass production due to its easy operation and low cost.

Retrospect and prospect of Geographical Sciences in China： A comparison with the Strategic Directions for Geography in the USA

Understanding the Changing Planet： Strategic Directions for the Geographical Sciences （UCP）, published by the National Research Council （USA）, and its comments in The Professional Geographer propose that uppercase and plural ＂Geographical Sciences＂ （GS） is the strategic direction for geography in the next decade for better understanding of our rapidly changing planet. According to these comments, UCP valued technologies and tools exces- sively （＂task＂）, and did not pay much attention to methodology （＂discipline＂）. Actually, both ＂task＂ and ＂discipline＂ are geographical wings, especially in the time of ＂big science＂. Enlightenment from UCP and its comments is the strategic direction that should be balanced between ＂task＂ and ＂discipline＂, GS should be a three-dimensional construct of a disciplinary system, methodology, and technologies and tools, and this system should be scientific hu- manism based on scientific spirit and directed by humanism. During the last 60 years, Chi- nese geographers devoted themselves to GS, including practice and theory. Obviously pro- gress and outlook are proposed as interdisciplinary GS, Earth Surface Sciences （ESS） and Geographical Construction （GC）. The disciplinary system of GS is very complex, and is composed of such human knowledge domains as sciences, technologies, engineering, and philosophy. The main mission is to research the open, complex, and macro earth system （not only scientifically, but also humanistically）, and one significant methodology is ＂comprehen- sive integration of qualitative and quantitative means＂ （CIQQM）. At the same time, another changing direction in Chinese geography is Human-Economic Geography （HEG）.

Barium isotope cosmochemistry and geochemistry

While the isotopic variations of barium were reported for the first time fourty years ago, the number of studies on barium isotopes significantly increased only after 2010. Barium isotope anomalies in meteorites have been successfully used to provide constraints about the origin of presolar Si C grains. In carbonaceous chondrites Ba isotope anomalies are indicative of the heterogeneity of the early solar system, possibly resulting from of a later injection of material after the cooling of solar system. Barium isotope fractionation in the same carbonaceous chondrites suggests that a strong magnetic field was present in the innermost part of the early solar system. Barium mass-dependent isotope fractionation has also been detected throughout Earth surface materials. While igneous rocks show limited Ba isotopic variations, relatively large isotopic variations are observed amongst and within soils, rivers, and biological materials. Indeed, plants seem to fractionate Ba isotopes during Ba uptake from soil solutions.Therefore, Ba isotope signatures have the potential to provide clues on the biological cycling of Ba at the Earth surface. In seawater, Ba isotopic variations have been mapped out, and are mainly related to barite precipitation, which is in turn related to organic matter remineralization in the water column.This makes Ba isotopes a potentially powerful tool to reconstruct past ocean productivity, although constraints are still lacking regarding the inputs of dissolved Ba to the oceans by rivers or hydrothermalism.

Tribological properties of nanometer cerium oxide as additives in lithium grease

This paper presents a comparative study of the influence of nanometer-CeO_2（nano-CeO_2） and temperature on tribological and lubricating properties of lithium grease. The morphology and structure of nanocrystals were characterized by means of transmission electron microscopy（TEM） and X-ray diffraction（XRD）, respectively. Friction and wear tests were conducted on the friction and wear tester.Results show that the lithium grease with addition of nanometer-CeO_2 has much better friction-reducing and anti-wear performance than that of base grease. When the additive in grease is 0.6 wt%, the friction coefficient（COF） and wear scar diameter（WSD） decrease by 28% and 13% comparing with base grease,respectively. The base grease and grease with 0.6 wt% nanometer-CeO_2 both possess the lowest average COF and wear width at 50 ℃. The worn surface morphology after friction test was analyzed by scanning electron microscopy（SEM） and NANOVEA three-dimensional profilometer. Under the lubrication of the lithium grease containing 0.6 wt% nano-CeO_2. few shallow furrows can be observed on the quite smoothed surface and the WSD decreased. Moreover, It was found that the nano-CeO_2 has been incorporated into the surface protective and lubricious layer by energy dispersive spectrometer（EDS） analysis.

Modification of Cu/ZSM-5 catalyst with CeO_2 for selective catalytic reduction of NO_x with ammonia

Cu/ZSM-5 and CeO_2-modified Cu/ZSM-5 catalysts were prepared by a wetness impregnation method. The addition of CeO_2 was found to enhance the NO_x selective catalytic reduction（SCR） activity of the catalyst at low temperatures, but the high-temperature activity was weakened. The catalysts were characterized by X-ray diffraction（XRD）, nitrogen physisorption, inductively coupled plasma optical emission spectrometry（ICP-OES）, X-ray photoelectron spectroscopy（XPS）, electron paramagnetic resonance（EPR）, H_2 temperature-programmed reduction（TPR） and NH_3 temperature-programmed desorption（TPD）. The results showed that more CuO clusters instead of isolated Cu^（2＋） species were obtained on the modified catalyst. These active CuO clusters, as well as the Cu-Ce synergistic effect, improved the redox property of the catalyst and low-temperatures SCR activity via promoting the oxidation of NO to NO_2 and fast SCR reaction. The loss in high-temperatures activity was attributed to the enhanced competitive oxidation of NH_3 by O_2 and decreased surface acidity of the catalyst.