We use conditional nonlinear optimal perturbation （CNOP） to investigate the optimal precursory disturbances in the Zebiak- Cane El Nino-Southern Oscillation （ENSO） model. The conditions of the CNOP-type precursors...We use conditional nonlinear optimal perturbation （CNOP） to investigate the optimal precursory disturbances in the Zebiak- Cane El Nino-Southern Oscillation （ENSO） model. The conditions of the CNOP-type precursors are highly likely to evolve into El Nino events in the Zebiak-Cane model. By exploring the dynamic behaviors of these nonlinear El Nino events caused by the CNOP-type precursors, we find that they, as expected, tend to phase-lock to the annual cycles in the Zebiak-Cane model with the SSTA peak at the end of a calendar year. However, E1 Nino events with CNOPs as initial anomalies in the linearized Zebiak-Cane model are inclined to phase-lock earlier than nonlinear E1 Nino events despite the existence of annual cycles in the model. It is clear that nonlinearities play an important role in El Nino＇s phase-locking. In particular, nonlinear temperature advection increases anomalous zonal SST differences and anomalous westerlies, which weakens anomalous upwelling and acts on the increasing anomalous vertical temperature difference and, as a result, enhances E1 Nino and then delays the peak SSTA. Finally, we demonstrate that nonlinear temperature advection, together with the effect of the annual cycle, causes El Nino events to peak at the end of the calendar year.展开更多
MicroRNAs(miRNAs) are small non-coding RNAs that regulate a variety of biological processes. miRNA expression often exhibits spatial and temporal specificity. However, genome-wide miRNA expression patterns in differen...MicroRNAs(miRNAs) are small non-coding RNAs that regulate a variety of biological processes. miRNA expression often exhibits spatial and temporal specificity. However, genome-wide miRNA expression patterns in different organs during development of Arabidopsis thaliana have not yet been systemically investigated. In this study, we sequenced small RNA libraries generated from 27 different organ/tissue types, which cover the entire life cycle of Arabidopsis. Analysis of the sequencing data revealed that most miRNAs are ubiquitously expressed, whereas a small set of miRNAs display highly specific expression patterns. In addition, different miRNA members within the same family have distinct spatial and temporal expression patterns. Moreover, we found that some miRNAs are produced from different arms of their hairpin precursors at different developmental stages. This work provides new insights into the regulation of miRNA biogenesis and a rich resource for future investigation of miRNA functions in Arabidopsis.展开更多
基金sponsored by the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KZCX2-YW-QN203)the National Basic Research Program of China(Grant Nos.2010CB950400&2012CB955202)the National Natural Science Foundation of China(Grant No.41176013)
文摘We use conditional nonlinear optimal perturbation （CNOP） to investigate the optimal precursory disturbances in the Zebiak- Cane El Nino-Southern Oscillation （ENSO） model. The conditions of the CNOP-type precursors are highly likely to evolve into El Nino events in the Zebiak-Cane model. By exploring the dynamic behaviors of these nonlinear El Nino events caused by the CNOP-type precursors, we find that they, as expected, tend to phase-lock to the annual cycles in the Zebiak-Cane model with the SSTA peak at the end of a calendar year. However, E1 Nino events with CNOPs as initial anomalies in the linearized Zebiak-Cane model are inclined to phase-lock earlier than nonlinear E1 Nino events despite the existence of annual cycles in the model. It is clear that nonlinearities play an important role in El Nino＇s phase-locking. In particular, nonlinear temperature advection increases anomalous zonal SST differences and anomalous westerlies, which weakens anomalous upwelling and acts on the increasing anomalous vertical temperature difference and, as a result, enhances E1 Nino and then delays the peak SSTA. Finally, we demonstrate that nonlinear temperature advection, together with the effect of the annual cycle, causes El Nino events to peak at the end of the calendar year.
基金supported by grants fromNational Key Research and Development Program of China (2016YFA0500800)National Natural Science Foundation of China (31421001, 31225015) to Yijun Qi
文摘MicroRNAs(miRNAs) are small non-coding RNAs that regulate a variety of biological processes. miRNA expression often exhibits spatial and temporal specificity. However, genome-wide miRNA expression patterns in different organs during development of Arabidopsis thaliana have not yet been systemically investigated. In this study, we sequenced small RNA libraries generated from 27 different organ/tissue types, which cover the entire life cycle of Arabidopsis. Analysis of the sequencing data revealed that most miRNAs are ubiquitously expressed, whereas a small set of miRNAs display highly specific expression patterns. In addition, different miRNA members within the same family have distinct spatial and temporal expression patterns. Moreover, we found that some miRNAs are produced from different arms of their hairpin precursors at different developmental stages. This work provides new insights into the regulation of miRNA biogenesis and a rich resource for future investigation of miRNA functions in Arabidopsis.
