8 resultados para Dominic Gagnon
em Publishing Network for Geoscientific
Resumo:
The present dataset contain source data for Figure 5a from Schilling et al., 2009. Cell fate decisions are regulated by the coordinated activation of signalling pathways such as the extracellular signal-regulated kinase (ERK) cascade, but contributions of individual kinase isoforms are mostly unknown. The authors combined quantitative data from erythropoietin-induced pathway activation in primary erythroid progenitor (colony-forming unit erythroid stage, CFU-E) cells with mathematical modelling, in order to predict and experimentally confirmed a distributive ERK phosphorylation mechanism in CFU-E cells. The authors found evidences that double-phosphorylated ERK1 attenuates proliferation beyond a certain activation level, whereas activated ERK2 enhances proliferation with saturation kinetics. Phosphorylation levels of JAK2 at 7 min after stimulation for Epo concentrations ranging from 0.1 to 1000 U/ml were simulated.
Resumo:
The present dataset contain source data for Figure 5b from Schilling et al., 2009. Cell fate decisions are regulated by the coordinated activation of signalling pathways such as the extracellular signal-regulated kinase (ERK) cascade, but contributions of individual kinase isoforms are mostly unknown. The authors combined quantitative data from erythropoietin-induced pathway activation in primary erythroid progenitor (colony-forming unit erythroid stage, CFU-E) cells with mathematical modelling, in order to predict and experimentally confirmed a distributive ERK phosphorylation mechanism in CFU-E cells. The authors found evidences that double-phosphorylated ERK1 attenuates proliferation beyond a certain activation level, whereas activated ERK2 enhances proliferation with saturation kinetics. They show integrated responses of double-phosphorylated ERK1 and ERK2 that were calculated for different Epo concentrations for the original model as well as for models with elevated ERK1 or ERK2 levels.
Resumo:
The present dataset data contain source data for Figure 5a from Schilling et al., 2009. Cell fate decisions are regulated by the coordinated activation of signalling pathways such as the extracellular signal-regulated kinase (ERK) cascade, but contributions of individual kinase isoforms are mostly unknown. The authors combined quantitative data from erythropoietin-induced pathway activation in primary erythroid progenitor (colony-forming unit erythroid stage, CFU-E) cells with mathematical modelling, in order to predict and experimentally confirmed a distributive ERK phosphorylation mechanism in CFU-E cells. The authors found evidences that double-phosphorylated ERK1 attenuates proliferation beyond a certain activation level, whereas activated ERK2 enhances proliferation with saturation kinetics. CFU-E cells were stimulated with the indicated Epo concentrations for 7 min and phosphorylation levels were determined by quantitative immunoblotting.
Resumo:
Data contain source data for Figure 5c from Schilling et al., 2009. Cell fate decisions are regulated by the coordinated activation of signalling pathways such as the extracellular signal-regulated kinase (ERK) cascade, but contributions of individual kinase isoforms are mostly unknown. The authors combined quantitative data from erythropoietin-induced pathway activation in primary erythroid progenitor (colony-forming unit erythroid stage, CFU-E) cells with mathematical modelling, in order to predict and experimentally confirmed a distributive ERK phosphorylation mechanism in CFU-E cells. The authors found evidences that double-phosphorylated ERK1 attenuates proliferation beyond a certain activation level, whereas activated ERK2 enhances proliferation with saturation kinetics. Retrovirally transduced CFU-E cells were incubated with increasing Epo concentrations for 14 h and proliferation was measured by [3H]-thymidine incorporation.
Resumo:
Recent intensification of wind-driven upwelling of warm upper circumpolar deep water (UCDW) has been linked to accelerated melting of West Antarctic ice shelves and glaciers. To better assess the long term relationship between UCDWupwelling and the stability of theWest Antarctic Ice Sheet, we present a multi-proxy reconstruction of surface and bottom water conditions in Marguerite Bay, West Antarctic Peninsula (WAP), through the Holocene. A combination of sedimentological, diatom and foraminiferal records are, for the first time, presented together to infer a decline in UCDW influence within Marguerite Bay through the early to mid Holocene and the dominance of cyclic forcing in the late Holocene. Extensive glacial melt, limited sea ice and enhanced primary productivity between 9.7 and 7.0 ka BP is considered to be most consistent with persistent incursions of UCDW through Marguerite Trough. From 7.0 ka BP sea ice seasons increased and productivity decreased, suggesting that UCDW influence within Marguerite Bay waned, coincident with the equatorward migration of the Southern Hemisphere Westerly Winds (SWW). UCDW influence continued through the mid Holocene, and by 4.2 ka BP lengthy sea ice seasons persisted within Marguerite Bay. Intermittent melting and reforming of this sea ice within the late Holocene may be indicative of episodic incursions of UCDW into Marguerite Bay during this period. The cyclical changes in the oceanography within Marguerite Bay during the late Holocene is consistent with enhanced sensitively to ENSO forcing as opposed to the SWW-forcing that appears to have dominated the early to mid Holocene. Current measurements of the oceanography of the WAP continental shelf suggest that the system has now returned to the early Holocene-like oceanographic configuration reported here, which in both cases has been associated with rapid deglaciation.
Resumo:
A total of 51,074 archaeological sites from the early Neolithic to the early Iron Age (c. 8000-500 BC), with a spatial extent covering most regions of China (c. 73-131°E and c. 20-53°N), were analysed over space and time in this study. Site maps of 25 Chinese provinces, autonomous regions and municipalities, published in the series 'Atlas of Chinese Cultural Relics', were used to extract, digitalise and correlate its archaeological data. The data were, in turn, entered into a database using a self-developed mapping software that makes the data, in a dynamic way, analysable as a contribution to various scientific questions, such as population growth and migrations, spread of agriculture and changes in subsistence strategies. The results clearly show asynchronous patterns of changes between the northern and southern parts of China (i.e. north and south of the Yangtze River, respectively) but also within these macro-regions. In the northern part of China (i.e. along the Yellow River and its tributaries and in the Xiliao River basin), the first noticeable increase in the concentration of Neolithic sites occurred between c. 5000 and 4000 BC; however, highest site concentrations were reached between c. 2000 and 500 BC. Our analysis shows a radical north-eastern shift of high site-density clusters (over 50 sites per 100 * 100 km grid cell) from the Wei and middle/lower Yellow Rivers to the Liao River system sometime between 2350 BC and 1750 BC. This shift is hypothetically discussed in the context of the incorporation of West Asian domesticated animals and plants into the existing northern Chinese agricultural system. In the southern part of China, archaeological sites do not show a noticeable increase in the absolute number of sites until after c. 1500 BC, reaching a maximum around 1000 BC.
Resumo:
Precise relative sea level (RSL) data are important for inferring regional ice sheet histories, as well as helping to validate numerical models of ice sheet evolution and glacial isostatic adjustment. Here we develop a new RSL curve for Fildes Peninsula, South Shetland Islands (SSIs), a sub-Antarctic archipelago peripheral to the northern Antarctic Peninsula ice sheet, by integrating sedimentary evidence from isolation basins with geomorphological evidence from raised beaches. This combined approach yields not only a Holocene RSL curve, but also the spatial pattern of how RSL change varied across the archipelago. The curve shows a mid-Holocene RSL highstand on Fildes Peninsula at 15.5 m above mean sea level between 8000 and 7000 cal a BP. Subsequently RSL gradually fell as a consequence of isostatic uplift in response to regional deglaciation. We propose that isostatic uplift occurred at a non-steady rate, with a temporary pause in ice retreat ca. 7200 cal a BP, leading to a short-lived RSL rise of ~1 m and forming a second peak to the mid-Holocene highstand. Two independent approaches were taken to constrain the long-term tectonic uplift rate of the SSIs at 0.22-0.48 m/ka, placing the tectonic contribution to the reconstructed RSL highstand between 1.4 and 2.9 m. Finally, we make comparisons to predictions from three global sea level models.