1,746,942 research outputs found
(Table 1) Age control points and of sediment core MD01-2444
No full textThe marine isotopic stage 3 (MIS3) at Ocean Drilling Program (ODP) Site 1060 (Gulf Stream) shows both sharp onset and end of interstadials, the existence of very short lived warm events during stadials, and points to differences in detail between the sea surface temperature (SST) record from the western North Atlantic and the atmospheric temperature record inferred from d18O in Greenland ice. Investigating MIS3 and obtaining comparable data from other locations appears crucial. The eastern Atlantic provides well-documented records of climate changes. We have selected a core from off Portugal and use it to examine Dansgaard/Oeschger events (D/O) at centennial-scale resolution (139 years on average between two data points). We have obtained a faunal data set for core MD01-2444, 37°N, 10°W, 2600 m water depth and use a group of species (Globigerina bulloides + Globigerinita glutinata) as a proxy of upwelling intensity driven by trade winds intensity changes. We tentatively relate the variation of this group to a North Atlantic Oscillation-like phenomenon (NAO) off Portugal. We observe that it resembles the rainfall index in the Caribbean as recorded at ODP Site 1002 (Cariaco Basin) which traces the Intertropical Convergence Zone (ITCZ) location through changes of terrigenous inputs. The driest intervals (ITZC to the south) at Site 1002 correspond to intervals of increased upwelling in MD01-2444 as well as the driest periods identified during stadials on similar cores in the area. Because the ITZC to the south is consistent with an El Niño–Southern Oscillation (ENSO+) situation, our study suggests a positive correlation between ENSO-like conditions and NAO-like conditions at a millennial timescale. During interstadial intervals when increased wetness over Cariaco is recorded (ITCZ to the north) and the upwelling in MD01-2444 is decreased, we see from both SSTs and faunal tropical indicators that MD01-2444 site is warm. In addition, interstadials are equally warm through each so-called Bond cycle. This contrasts with the Greenland Ice Core Project (GRIP) record where interstadial peaks are successively cooler through each Bond cycle. This record confirms a link between tropical climate linked to ITCZ position and the climate of southern Europe at millennial timescales, in spite of showing a very good correlation with polar latitudes (GRIP) through d18O on Globigerina bulloides. In addition, because the warmest SSTs and the d18O on G. bulloides are so remarkably different, our work points to changes in seasonality as a strong control over the climatic pattern of the North Atlantic area and the marked influence of winter conditions
Southern Pacific (SP) 2444
No full textA photograph print showing the Southern Pacific (SP) 2444, 4-6-2, Oakland, CA
Santa Fe (ATSF) 2444
No full textA photograph print showing Santa Fe 2444, 2-8-0 Brooks), class 2442, ex: SFP&P No. 56
Southern Pacific (SP) 2444
No full textA photograph print showing the Southern Pacific (SP) 2444, 4-6-2, West Oakland, CA
Back to the future? Thoughts on the political economy of expanding state ownership in Russia
No full textThe period since early 2004 has a significant expansion of the direct role of the Russian state in owning and managing industrial assets, particular in ‘strategic sectors’ of the economy, such as power-generation machines, aviation, oil and finance. Increasingly, policy seems to have been focused less on market reforms than on tightening the state’s grip on the ‘commanding heights’ of the economy. Many factors contribute to this shift – factional, ideological, geopolitical and conjunctural – and, as will be argued below, there is not one single process at work, but several. This chapter seeks to understand what has been driving the expansion of state ownership in Russia over the recent past and what that expansion might imply for the future. Its central conclusion is that a great deal of the explanation for this trend is in fact structural. While press coverage and public discussion have largely focused on factional politics and the political conjuncture – particularly conflicts between the Kremlin and big business and rivalry among Kremlin ‘clans’ ahead of the Putin succession in 2008 – a deeper understanding of the growth of the state requires an examination of the interaction between state capacities and Russia’s industrial structure
Calcium carbonate and corresponding Ca/Ti ratios in sediment core MD01-2444
No full textA composite section was created by splicing Cores MD01-2444 and MD01-2443 together at ~194 ka. The splice tie point corresponds to a depth of 27.42 mbsf in MD01-2444 and 16.74 mbsf in Core MD01-2443
Age model of composite sediment core MD01-2444/2443
No full textA composite section was created by splicing Cores MD01-2444 and MD01-2443 together at ~194 ka. The splice tie point corresponds to a depth of 27.42 mbsf in MD01-2444 and 16.74 mbsf in Core MD01-2443. The age model is a modified version of the one derived by Barker et al. (2011) based on correlation of millennial variability in MD01-2444 and MD01-2443 records to a synthetic Greenland temperature record produced using the EPICA Dome C (EDC) ice core and placed on the absolute speleothem timescale (GLt_syn age)
Coccolithosphores and fossil organic compounds of sediment core MD01-2444
No full textThis study analyzes coccolithophore abundance fluctuations (e.g., Emiliania huxleyi, Gephyrocapsa specimens, and Florisphaera profunda) in core MD01-2444 sediment strata retrieved at the Iberian Margin, northeastern Atlantic Ocean. Coccolithophores are calcareous nannofossils, a major component of the oceanic phytoplankton, which provide information about past ecological and climatological variability. Results are supported by data on fossil organic compounds (sea surface temperatures, alkenones, and n-hexacosan-1-ol index) and geochemical analyses (benthic d13Ccc and planktonic d18Occ isotopes). Three scenarios are taken into account for this location at centennial-scale resolution over the last 70,000 years: the Holocene and the stadial and interstadial modes. The different alternatives are described by means of elements such as nutrients; upwelling phenomena; temperatures at surface and subsurface level; or the arrival of surface turbid, fresh, and cold waters due to icebergs, low sea level, increased aridity, and dust. During the Holocene, moderate primary productivity was observed (mainly concentrated in E. huxleyi specimens); surface temperatures were at maxima while the water column was highly ventilated by northern-sourced polar deep waters and warmer subsurface, nutrient-poor subtropical waters. Over most of the last glacial stadials, surface productivity weakened (higher F. profunda and reworked specimen percentages and lower diunsaturated and triunsaturated C37 alkenones); the arrival of cold Arctic surface waters traced by tetraunsaturated C37 peaks and large E. huxleyi, together with powerful ventilated southern-sourced polar deep waters, disturbed, in all likelihood, the delicate vertical equilibrium while preventing significant upwelling mixing. Finally, during the last glacial interstadials (lower F. profunda percentages, nonreworked material, and higher diunsaturated and triunsaturated C37 alkenones) a combined signal is observed: warm surface temperatures were concurrent with generally low oxygenation of the deep-sea floor, moderate arrival of northern-sourced deep waters, and subsurface cold, nutrient-rich, recently upwelled waters, probably of polar origin; these particular conditions may have promoted vertical mixing while enhancing surface primary productivity (mainly of Gephyrocapsa specimens)
- …
