Response to climate change of different tree species and NDVI variation since 1923 in the middle arid region of Ningxia,China

The normalized difference vegetation index （NDVI） is used extensively to describe vegetation cover and ecological environ- ment change. The purpose of this study was to contrast the response of different tree species growing in the same habitat to climate change and retrieve past NDVI using tree-ring width data from tree cores collected from the transitional zone of Pinus tabulaeformis and Picea crassifolia in the Luoshan Mountains in the middle arid region of Ningxia. Correlation analysis indi- cated that radial growth ofP tabulaeJbrmis is more sensitive to precipitation and temperature change than that ofP crassifolia. Natural factors such as water availability and heat at this elevation are more suited to the growth ofP crassifolia, and are more advantageous to its renewal and succession. P. crassifolia is probably the better of the two species for protecting the forest ecosystem and conserving water in the Luoshan desertification area. Ring width of P. crassifolia correlates significantly with average NDVI for April-May （r =0.641, p 〈0.01）, and both of them are influenced positively by precipitation in April-May. The reconstructed NDVI for 1923-2007 shows the relatively low vegetation cover occurred in the 1920s-1930s, the 1960s-1970s, and the early 21 st century. The reconstructed NDVI better reflected the drought climate in the study area.

Comprehensive study on genetic pathways and parent materials of secondary biogenic gas in coalbeds

The types of substances in coal rock used by microbes,the specific ways in which microbes produce secondary biogenic gas(SBG)and whether substances exist in the coal seam for the formation of a large amount of SBG are important basic scientific issues.This paper conducts a systematic and comprehensive research study on the above issues using methods such as the isotopic tracing of gas,the analysis of coal organic geochemistry,and gas-producing simulation experiments of coal.Results show that the formation of SBG is by the microbial reduction of CO2and the SBG-producing coal seam undergoes microbial degradation.The thermogenic heavy gaseous hydrocarbons have also been degraded by microorganisms and possibly transformed into microbialoriginated CO2.A large amount of CO2,a relatively large amount of H2and a certain amount of heavy gaseous hydrocarbons may form in the thermal evolution of coal.These substances and the microbial-originated CO2and coal seam water can finally become parent materials of SBG.These components are rich in coal seams of medium–low thermal evolution,which should be the main coal seams for SBG formation and exploration.

Asynchronous Brain-Computer Interface Shared Control of Robotic Grasping

The control of a high Degree of Freedom(DoF) robot to grasp a target in three-dimensional space using Brain-Computer Interface(BCI) remains a very difficult problem to solve. Design of synchronous BCI requires the user perform the brain activity task all the time according to the predefined paradigm; such a process is boring and fatiguing. Furthermore, the strategy of switching between robotic auto-control and BCI control is not very reliable because the accuracy of Motor Imagery(MI) pattern recognition rarely reaches 100%. In this paper, an asynchronous BCI shared control method is proposed for the high DoF robotic grasping task. The proposed method combines BCI control and automatic robotic control to simultaneously consider the robotic vision feedback and revise the unreasonable control commands. The user can easily mentally control the system and is only required to intervene and send brain commands to the automatic control system at the appropriate time according to the experience of the user. Two experiments are designed to validate our method: one aims to illustrate the accuracy of MI pattern recognition of our asynchronous BCI system; the other is the online practical experiment that controls the robot to grasp a target while avoiding an obstacle using the asynchronous BCI shared control method that can improve the safety and robustness of our system.

Preface

信号处理的所有光的实现由于这条途径的唯一的潜力吸引了很多注意克服带宽和电子设备的速度瓶颈。许多所有光的信号处理技术，出现处理带宽直到几 THz，在大量区域被建议了并且成功地采用了例如 ultrafast 电信，光计算，微波 photonics，和 bio-photonics [17 ] 。

Evolutionary and Functional Analysis of the Key Pluripotency Factor Oct4 and Its Family Proteins

Oct4 is one of the key pluripotent factors essential for embryonic stem cells and induced pluripotent stem （iPS） cells. Oct4 belongs to the POU domain family, which contains multiples genes with various important functions. Although the function of Oct4 has been extensively studied, detailed comparison of Oct4 with other POU family genes and their evolutionary analysis are still lacking. Here, we systematically identified POU family genes from lower to higher animal species. We observed an expansion of POU family genes in vertebrates, with an additional increment in mammalian genomes. We analyzed the phylogenetic relationship, tissue specific expression profiles and regulatory networks of POU family genes of the human genome, and predicted the putative binding microRNAs of human POU family genes. These results provide the first comprehensive evolutionary and comparative analysis of POU family genes, which will help to better understand the relationships among POU family genes and shed light on their future functional studies.