Why did the apartheid’s endgame favor the African National Congress (ANC) over other contenders? This article advances a path dependence argument, hypothesizing Mandela’s 1962 trip across Africa as a “critical junc...Why did the apartheid’s endgame favor the African National Congress (ANC) over other contenders? This article advances a path dependence argument, hypothesizing Mandela’s 1962 trip across Africa as a “critical juncture” whose arc of counter-intuitive developments narrowed the ruling National Party’s bargaining options down to its worst enemy—Mandela’s ANC.展开更多
An extensive study of ring current injection and intensification of the storm-time symmetric ring current is conducted with three-dimensional (3-D) test particle trajectory calculations (TPTCs) in this paper. TPTCs re...An extensive study of ring current injection and intensification of the storm-time symmetric ring current is conducted with three-dimensional (3-D) test particle trajectory calculations (TPTCs) in this paper. TPTCs reveal more accurately the process of ring current injection. The main results are the following: (1) an intense convection electric field can effec-tively energize and inject plasma sheet particles into ring current region within 1-3 h. (2) Injection ions often follow chaotic trajectories in non-adiabatic regions,which may have implications in storm and ring current physics. (3) The shielding electric field, which arises as a consequence of enhanced convection and co-exists with injection and convection electric field, leads the original open trajectories to change into closed ones, thus may play an important role in the formation of the symmetric ring current.展开更多
Determining how cells regulate their transcriptional response toextracellular signals is key to the understanding of complex eukaryotic systems. This study wasinitiated with the goals of furthering the study of mammal...Determining how cells regulate their transcriptional response toextracellular signals is key to the understanding of complex eukaryotic systems. This study wasinitiated with the goals of furthering the study of mammalian transcriptional regulation andanalyzing the relative benefits of related computational methodologies. One dataset available forsuch an analysis involved gene expression profiling of the early growth factor response to plateletderived growth factor (PDGF) in a human glioblastoma cell line; this study differentiated geneswhose expression was regulated by signaling through the phosphoinositide-3-kinase (PI3K) versus theextracellular-signal regulated kinase (ERK) pathways. We have compared the inferred transcriptionfactors from this previous study with additional predictions of regulatory transcription factorsusing two alternative promoter sequence analysis techniques. This comparative analysis, in which thealgorithms predict overlapping, although not identical, sets of factors, argues for meticulousbenchmarking of promoter sequence analysis methods to determine the positive and negative attributesthat contribute to their varying results. Finally, we inferred transcriptional regulatory networksderiving from various signaling pathways using the CARRIE program suite. These networks not onlyincluded previously described transcriptional features of the response to growth signals, but alsopredicted new regulatory features for the propagation and modulation of the growth signal.展开更多
文摘Why did the apartheid’s endgame favor the African National Congress (ANC) over other contenders? This article advances a path dependence argument, hypothesizing Mandela’s 1962 trip across Africa as a “critical juncture” whose arc of counter-intuitive developments narrowed the ruling National Party’s bargaining options down to its worst enemy—Mandela’s ANC.
文摘An extensive study of ring current injection and intensification of the storm-time symmetric ring current is conducted with three-dimensional (3-D) test particle trajectory calculations (TPTCs) in this paper. TPTCs reveal more accurately the process of ring current injection. The main results are the following: (1) an intense convection electric field can effec-tively energize and inject plasma sheet particles into ring current region within 1-3 h. (2) Injection ions often follow chaotic trajectories in non-adiabatic regions,which may have implications in storm and ring current physics. (3) The shielding electric field, which arises as a consequence of enhanced convection and co-exists with injection and convection electric field, leads the original open trajectories to change into closed ones, thus may play an important role in the formation of the symmetric ring current.
文摘Determining how cells regulate their transcriptional response toextracellular signals is key to the understanding of complex eukaryotic systems. This study wasinitiated with the goals of furthering the study of mammalian transcriptional regulation andanalyzing the relative benefits of related computational methodologies. One dataset available forsuch an analysis involved gene expression profiling of the early growth factor response to plateletderived growth factor (PDGF) in a human glioblastoma cell line; this study differentiated geneswhose expression was regulated by signaling through the phosphoinositide-3-kinase (PI3K) versus theextracellular-signal regulated kinase (ERK) pathways. We have compared the inferred transcriptionfactors from this previous study with additional predictions of regulatory transcription factorsusing two alternative promoter sequence analysis techniques. This comparative analysis, in which thealgorithms predict overlapping, although not identical, sets of factors, argues for meticulousbenchmarking of promoter sequence analysis methods to determine the positive and negative attributesthat contribute to their varying results. Finally, we inferred transcriptional regulatory networksderiving from various signaling pathways using the CARRIE program suite. These networks not onlyincluded previously described transcriptional features of the response to growth signals, but alsopredicted new regulatory features for the propagation and modulation of the growth signal.