Aeolian particle transport inferred using a ~150-year sediment record from Sayram Lake, arid northwest China

We studied sediment cores from Sayram Lake in the Tianshan Mountains of northwest China to evaluate variations in aeolian transport processes over the past ~150 years. Using an end-member modeling algorithm of particle size data, we interpreted end members with a strong bimodal distribution as having been transported by aeolian processes, whereas other end members were interpreted to have been transported by fluvial processes. The aeolian fraction accounted for an average of 27% of the terrigenous components in the core. We used the ratio of aeolian to fluvial content in the Sayram Lake sediments as an index of past intensity of aeolian transport in the Tianshan Mountains. During the interval 1910-1930, the index was high, reflecting the fact that dry climate provided optimal conditions for aeolian dust transport. From 1930-1980, the intensity of aeolian transport was weak. From the 1980s to the 2000s, aeolian transport to Sayram Lake increased. Although climate in northwest China became more humid in the mid-1980s, human activity had by that time altered the impact of climate on the landscape, leading to enhanced surface erosion, which provided more transportable material for dust storms. Comparison of the Lake Sayram sediment record with sediment records from other lakes in the region indicates synchronous intervals of enhanced aeolian transport from 1910 to 1930 and 1980 to 2000.</p

Environmental variability and human activity over the past 140 years documented by sediments of Ebinur Lake in arid central Asia

A short (50-cm-long) sediment core from Ebinur Lake in arid central Asia has been analyzed for various environmental proxies, including organic matter content, δ13C in organic matter, magnetic susceptibility, heavy metal contents, and stable isotopic compositions of bulk carbonate (δ18O and δ13C). The results reveal that the evolutionary stages inferred from environmental indicators have an asynchronous nature. If the asynchrony of periodic changes in multi-environmental proxies is ignored, important information may be lost, especially regarding anthropogenic influences. On the basis of magnetic susceptibility and heavy metal contents, human activities appear to have resulted in increases in surface erosion and measurable heavy-metal accumulation from the mid-1960s, whereas the organic matter contents, which display an obvious shift in the late 1930s, correlate with regional climate. However, the changes in the stable isotopes of bulk carbonate are mainly controlled by the isotopic composition of the host water which is generally consistent with the lake level. From the late 1870s to the 1960s, the lake was in a natural evolutionary state. From the 1960s to the mid-2000s, the runoff feeding Ebinur Lake dropped rapidly, in association with a sharp increase in agricultural development. Finally, beginning in the early twenty-first century, the climate became wetter than during the earlier two stages, and as agricultural water demand decreased, surface runoff once again increased. It is noted that, although the different proxies respond differently to climate changes and human activities, any analysis of environmental evolution should consider them each individually, in order to fully understand the complex interactions between climate and human influence. </p

The Revision and Application of Aurora in China: Based on Successful Intelligence

Aurora Battery is a corresponding test of successful intelligence. This study aims to examine the factorial structure of the Chinese version of Aurora Battery and to investigate its internal consistency and validity, as well as to discover the developmental features of Chinese students. A total number of 2007 students were recruited from 13 schools across eastern, central, and western China, ranging from 4th to 8th grade (mean age = 12.29 years) and among them, 43.9% are girls. Confirmatory factor analysis (CFA) was used to examine the factorial structure. Among the tested models, a second-order factor model, in which the three ability factors serve as indicators of a general factor, provided an acceptable model fit to the data. Moreover, measurement invariance across gender and grades were supported, which suggests the mean scores of analytical, creative, and practical abilities are comparable in this research. The criterion-related validity analysis suggests that the battery and its three subscales have good criterion validity. The scale reliability analysis shows that the Cronbach&#39;s alpha and the McDonald&#39;s omega value of the whole test were .84 and .87, respectively, indicating the scale&#39;s internal reliability is good. For ability differences among grades, students&#39; analytical and practical abilities increase across all grades, while creativity presents an upward trend from grade 4 to 6, followed by a downward trend from grade 6 to 7, and an increase from grade 7 to 8. Female students outperform male students on both analytical and creative ability, while with no obvious difference on practical abilities.</p

Geochemical Responses to Anthropogenic and Natural Influences in Ebinur Lake Sediments of Arid Northwest China

<div><p>Geochemical concentrations were extracted for a short sediment core from Ebinur Lake, located in arid northwest China, and mathematical methods were used to demonstrate the complex pattern of the geochemical anomalies resulting from the temporal changes in natural and anthropogenic forces on the lake sediments. The first element assemblage (C1) (aluminum, potassium, iron, magnesium, beryllium, etc.) was predominantly terrigenous; among the assemblage, total phosphorus and titanium were generally consistent with aluminum except with regards to their surface sequences, which inferred the differences of source regions for terrigenous detrital material led to this change around ca. 2000AD. The second assemblage (C2) (calcium and strontium) was found to have a negative relationship with aluminum through a cluster analysis. The third assemblage (C3) included sodium and magnesium, which were influenced by the underwater lake environment and deposited in the Ebinur depression. The concentration ratio of C1/(C1+C2) was used as an indicator for denudation amount of detrital materials, which was supported by the values of magnetic susceptibility. The enrichment factors for heavy metals suggested that the influence of human activities on heavy-metal enrichment in Ebinur Lake region was not severe over the past century. Prior to the 1960s, geochemical indicators suggested a stable lacustrine environment with higher water levels. Beginning in the 1960s, high agricultural water demand resulted in rapid declines in lake water level, with subsequent increases of lake water salinity, as evidenced by enhanced sodium concentration in lake core sediments. During this period, anthropogenic activity also enhanced the intensity of weathering and the denudation of the Ebinur watershed.</p></div

Quantification of Root Anatomical Traits in RGP Transgenic Maize Plants Based on Micro-CT

International audienceThe RGP transgenic plants show good resistance to drought especially reflected in corn yield. However, little is known about root traits which contribute to drought resistance. Here, we characterized root anatomy in the transgenic plants based on micro-CT scanning. Quantitative analysis of root anatomical traits showed that the drought-resistant RGP transgenic plants had larger root and stele cross-sectional areas in the fourth and the fifth whorls of nodal roots. The metaxylem vessel number and total area of metaxylem vessels was higher or larger in the fifth and the sixth whorls of nodal roots from RGP transgenic plants

Hierarchical clustering of geochemical elements in the Ebinur Lake sediment core.

<p>Hierarchical clustering of geochemical elements in the Ebinur Lake sediment core.</p

Geochemical evolution of the Ebinur Lake sediment core compared with the lake surface area change with axis scale in reverse, and meteorological data in the surrounding area.

<p>Geochemical evolution of the Ebinur Lake sediment core compared with the lake surface area change with axis scale in reverse, and meteorological data in the surrounding area.</p

The specific activity of ¹³⁷Cs, ²²⁶Ra and total ²¹⁰Pb activity in Ebinur Lake core sediment and the profiles for elemental concentrations in Ebinur Lake core sediment.

<p>The specific activity of ¹³⁷Cs, ²²⁶Ra and total ²¹⁰Pb activity in Ebinur Lake core sediment and the profiles for elemental concentrations in Ebinur Lake core sediment.</p