This study used time-series of global inventory modeling and mapping studies （GIMMS） normalized difference vegetation index （NDVI） datasets at a spatial resolution of 8 km and 15-d interval to investigate the spat...This study used time-series of global inventory modeling and mapping studies （GIMMS） normalized difference vegetation index （NDVI） datasets at a spatial resolution of 8 km and 15-d interval to investigate the spatial patterns of cropland phenology in China. A smoothing algorithm based on an asymmetric Gaussian function was first performed on NDVI dataset to minimize the effects of anomalous values caused by atmospheric haze and cloud contamination. Subsequent processing for identifying cropping systems and extracting phenological parameters, the starting date of growing season （SGS） and the ending date of growing season （EGS） was based on the smoothed NVDI time-series data. The results showed that the cropping systems in China became complex as moving from north to south of China. Under these cropping systems, the SGS and EGS for the first growing season varied largely over space, and those regions with multiple cropping systems generally presented a significant advanced SGS and EGS than the regions with single cropping patterns. On the contrary, the phenological events of the second growing season including both the SGS and EGS showed little difference between regions. The spatial patterns of cropping systems and phenology in Chinese cropland were highly related to the geophysical environmental factors. Several anthropogenic factors, such as crop variety, cultivation levels, irrigation, and fertilizers, could profoundly influence crop phenological status. How to discriminate the impacts of biophysical forces and anthropogenic drivers on phenological events of cultivation remains a great challenge for further studies.展开更多
Background Prior research about N400 has been mainly based on English stimuli,while the cognitive.processing of Chinese characters is still unclear.The aim of the present study was to further investigate the semantic ...Background Prior research about N400 has been mainly based on English stimuli,while the cognitive.processing of Chinese characters is still unclear.The aim of the present study was to further investigate the semantic processing of Chinese idioms.Methods Event related potentials （ERP） component N400 was elicited by 38 pairs of matching （congruent） and mismatching （incongruent） ended Chinese idioms：ending words with same phoneme but different shape and meaning （sPdSdM）,with similar shape but different phoneme and meaning（sSdPdM）,with same meaning but different phoneme and shape（sMdPdS）,and words with different phoneme,shape and meaning（dPdSdM）and recorded by Guangzhou Runjie WJ-1 ERP instruments.In 62 right-handed healthy adults（age 19-50 years）,N400 amplitudes and latencies were compared between matching and mismatching conditions at Fz,Cz and Pz.Results N400 showed a midline distribution and could be elicited in electrodes Fz, Cz and Pz.The mean values of N400 latencies and amplitudes were obtained for matching and mismatching ending werds in healthy adults.Significant differences were found in N400 latencies and amplitudes in matching and mismatching ending-werds idioms in healthy adults（P〈0.05）.Compared with matching ending-werds jdioms, N400 latencies were prolonged and the amplitudes were increased in mismatching ones.N400s elicited by different types of stimuli showed different latencies and amplitudes.and longest N400 latency and largest N400 amplitude were elicited by ending-werds with dPdSdM.No gender difference was found of N400 latency and amplitude in this study （P〉0.05）.Conclusions Compared with English stimuli.Chinese ideographic words could provide more flexible stimuli for N400 research in that the werds have 3-dimension changes-phoneme.shape and meaning.Features of N400 elicited by matching and mismatching ending words in Chinese idioms are mainly determined by the meaning of the werd.Some issues of N400 elicited by Chinese characters deserve further r展开更多
基金supported by the National Natural Science Foundation of China (40930101,40971218)the 948 Program,Ministry of Agriculture of China (2009-Z31)the Foundation for National Non-Profit Scientific Institution,Ministry of Finance of China (IARRP-2010-2)
文摘This study used time-series of global inventory modeling and mapping studies （GIMMS） normalized difference vegetation index （NDVI） datasets at a spatial resolution of 8 km and 15-d interval to investigate the spatial patterns of cropland phenology in China. A smoothing algorithm based on an asymmetric Gaussian function was first performed on NDVI dataset to minimize the effects of anomalous values caused by atmospheric haze and cloud contamination. Subsequent processing for identifying cropping systems and extracting phenological parameters, the starting date of growing season （SGS） and the ending date of growing season （EGS） was based on the smoothed NVDI time-series data. The results showed that the cropping systems in China became complex as moving from north to south of China. Under these cropping systems, the SGS and EGS for the first growing season varied largely over space, and those regions with multiple cropping systems generally presented a significant advanced SGS and EGS than the regions with single cropping patterns. On the contrary, the phenological events of the second growing season including both the SGS and EGS showed little difference between regions. The spatial patterns of cropping systems and phenology in Chinese cropland were highly related to the geophysical environmental factors. Several anthropogenic factors, such as crop variety, cultivation levels, irrigation, and fertilizers, could profoundly influence crop phenological status. How to discriminate the impacts of biophysical forces and anthropogenic drivers on phenological events of cultivation remains a great challenge for further studies.
基金This study was supported by the grants from the National Natural Science Foundation of China （No. 30770772 and No. 30971046）, the Fund of the Municipal Committee of Shanghai Science and Technology （No. 09411968200）, the Joint Key Project of New Frontier Technology in Shanghai Municipal Hospitals （No. SHDC12006105） and the National High Technology Research and Development Program of China （No. 2008AA02Z412 and No. 2007AA02Z420）.
文摘Background Prior research about N400 has been mainly based on English stimuli,while the cognitive.processing of Chinese characters is still unclear.The aim of the present study was to further investigate the semantic processing of Chinese idioms.Methods Event related potentials （ERP） component N400 was elicited by 38 pairs of matching （congruent） and mismatching （incongruent） ended Chinese idioms：ending words with same phoneme but different shape and meaning （sPdSdM）,with similar shape but different phoneme and meaning（sSdPdM）,with same meaning but different phoneme and shape（sMdPdS）,and words with different phoneme,shape and meaning（dPdSdM）and recorded by Guangzhou Runjie WJ-1 ERP instruments.In 62 right-handed healthy adults（age 19-50 years）,N400 amplitudes and latencies were compared between matching and mismatching conditions at Fz,Cz and Pz.Results N400 showed a midline distribution and could be elicited in electrodes Fz, Cz and Pz.The mean values of N400 latencies and amplitudes were obtained for matching and mismatching ending werds in healthy adults.Significant differences were found in N400 latencies and amplitudes in matching and mismatching ending-werds idioms in healthy adults（P〈0.05）.Compared with matching ending-werds jdioms, N400 latencies were prolonged and the amplitudes were increased in mismatching ones.N400s elicited by different types of stimuli showed different latencies and amplitudes.and longest N400 latency and largest N400 amplitude were elicited by ending-werds with dPdSdM.No gender difference was found of N400 latency and amplitude in this study （P〉0.05）.Conclusions Compared with English stimuli.Chinese ideographic words could provide more flexible stimuli for N400 research in that the werds have 3-dimension changes-phoneme.shape and meaning.Features of N400 elicited by matching and mismatching ending words in Chinese idioms are mainly determined by the meaning of the werd.Some issues of N400 elicited by Chinese characters deserve further r
