24 resultados para ELONGATION-FACTOR-P


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The loess sediment embedding the main Gravettian layer at the Krems-Wachtberg archaeological site facilitates exceptional preservation. To gain insight in the sedimentation process before and after the Paleolithic settlement, the magnetic fabric (preferential orientation of magnetic particles) of loess of the Krems-Wachtberg site is investigated. Magnetic fabric properties clearly show an eolian origin of the loess, but may indicate some relocation in the meter above the cultural layer. The magnetic fabric properties can be divided into three intervals, the top interval shows lowest foliation and inconsistent magnetic fabric directions. The middle interval around the main cultural layer shows low foliation, but a clear preferential NW - SE direction of the lineation. This lineation is interpreted as preferential direction of the eolian loess accumulation from the South-East. The interval below ca. 0.5 m underneath the main find horizon shows a northeast-southwest lineation, but an imbrication suggesting that sediment accumulation occurred perpendicular to this direction, similar to the interval around the find horizon.

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As reported by Shipboard Scientific Party (2001b, doi:10.2973/odp.proc.ir.191.104.2001) in the Site 1179 chapter of the Initial Reports volume, Leg 191 Site 1179 is located on abyssal seafloor northwest of Shatsky Rise, ~1650 km east of Japan. This part of the Pacific plate was formed during the Early Cretaceous, as shown by northeast-trending M-series magnetic lineations that become younger toward the northwest (Larson and Chase, 1972, doi:10.1130/0016-7606(1972)83[3627:LMEOTW]2.0.CO;2; Sager et al., 1988, doi:10.1029/JB093iB10p11753; Nakanishi et al., 1989, doi:10.1029/1999JB900002). The site is situated on magnetic Anomaly M8 (Nakanishi et al., 1999, doi:10.1029/1999JB900002), corresponding to an age of ~129 Ma and the Hauterivian stage of the Early Cretaceous (Gradstein et al., 1994, doi:10.1029/94JB01889; 1995). The sediments recovered at Site 1179 are split into four lithostratigraphic units based on composition and color (Shipboard Scientific Party, 2001b, doi:10.2973/odp.proc.ir.191.104.2001). Unit I (0-221.52 meters below seafloor [mbsf]) is a dominantly olive-gray clay- and radiolarian-bearing diatom ooze. Unit II (221.52-246.0 mbsf) is a yellowish brown to light brown clay-rich and diatom-bearing radiolarian ooze. Unit III (246.0-283.53 mbsf) is composed of brown pelagic clay. Unit IV (283.53-377.15 mbsf) is composed of chert and some porcellanite; any softer sediments present were washed out of the core barrel by the fluid circulating during the coring process.

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During Leg 134, the influence of ridge collision and subduction on the structural evolution of island arcs was investigated by drilling at a series of sites in the collision zone between the d'Entrecasteaux Zone (DEZ) and the central New Hebrides Island Arc. The DEZ is an arcuate Eocene-Oligocene submarine volcanic chain that extends from the northern New Caledonia Ridge to the New Hebrides Trench. High magnetic susceptibilities and intensities of magnetic remanence were measured in volcanic silts, sands, siltstones, and sandstones from collision zone sites. This chapter presents the preliminary results of studies of magnetic mineralogy, magnetic properties, and magnetic fabric of sediments and rocks from Sites 827 through 830 in the collision zone. The dominant carrier of remanence in the highly magnetic sediments and sedimentary rocks in the DEZ is low-titanium titanomagnetite of variable particle size. Changes in rock magnetic properties reflect variations in the abundance and size of titanomagnetite particles, which result from differences in volcanogenic contribution and the presence or absence of graded beds. Although the anisotropy of magnetic susceptibility results are difficult to interpret in terms of regional stresses because the cores were azimuthally unoriented, the shapes of the susceptibility ellipsoids provide information about deformation style. The magnetic fabric of most samples is oblate, dominated by foliation, as is the structural fabric. The variability of degree of anisotropy (P) and a factor that measures the shape of the ellipsoid (q) reflect the patchy nature of deformation, at a micrometer scale, that is elucidated by scanning electron microscope analysis. The nature of this patchiness implies that deformation in the shear zones is accomplished primarily by motion along bedding planes, whereas the material within the beds themselves remains relatively undeformed.

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Marine organisms have to cope with increasing CO2 partial pressures and decreasing pH in the oceans. We elucidated the impacts of an 8-week acclimation period to four seawater pCO2 treatments (39, 113, 243 and 405 Pa/385, 1,120, 2,400 and 4,000 µatm) on mantle gene expression patterns in the blue mussel Mytilus edulis from the Baltic Sea. Based on the M. edulis mantle tissue transcriptome, the expression of several genes involved in metabolism, calcification and stress responses was assessed in the outer (marginal and pallial zone) and the inner mantle tissues (central zone) using quantitative real-time PCR. The expression of genes involved in energy and protein metabolism (F-ATPase, hexokinase and elongation factor alpha) was strongly affected by acclimation to moderately elevated CO2 partial pressures. Expression of a chitinase, potentially important for the calcification process, was strongly depressed (maximum ninefold), correlating with a linear decrease in shell growth observed in the experimental animals. Interestingly, shell matrix protein candidate genes were less affected by CO2 in both tissues. A compensatory process toward enhanced shell protection is indicated by a massive increase in the expression of tyrosinase, a gene involved in periostracum formation (maximum 220-fold). Using correlation matrices and a force-directed layout network graph, we were able to uncover possible underlying regulatory networks and the connections between different pathways, thereby providing a molecular basis of observed changes in animal physiology in response to ocean acidification.