866 research outputs found

    Controls on the apex location of large deltas

    Get PDF
    Acknowledgements and Funding We would like to acknowledge the sponsors of the Fluvial Systems Research Group consortium BP, BG, Chevron, ConocoPhillips and Total. We would like to thank A. Felicia for image generation and database management.Peer reviewedPublisher PD

    Vertical trends within the prograding Salt Wash distributive fluvial system, SW USA

    Get PDF
    This work has been supported by the Fluvial Systems Research Group Consortium Phase 1, supported by BG, Chevron, Conoco Philips and Total. Discussions with John Howell on prograding sequences are greatly appreciated. The authors would also like to thank Anna Kulikova, Guy Prince, Kelsey McNamara and Karen Oud for assistance in the field. We thank reviewer Brian Willis, an anonymous reviewer and Editor Sebastien Castelltort for constructive comments that improved this manuscript.Peer reviewedPostprin

    Pressure dependence of Raman modes in double wall carbon nanotubes filled with α-Fe.

    Get PDF
    The preparation of highly anisotropic one-dimensional (1D) structures confined into carbon nanotubes (CNTs) in general is a key objective in CNTs research. In this work, the capillary effect was used to fill double wall carbon nanotubes with iron. The samples are characterized by Mössbauer and Raman spectroscopy, transmission electron microscopy, scanning area electron diffraction, and magnetization. In order to investigate their structural stability and compare it with that of single wall carbon nanotubes (SWNTs), elucidating the differences induced by the inner-outer tube interaction, unpolarized Raman spectra of tangential modes of double wall carbon nanotubes (DWNTs) filled with 1D nanocrystallin α-Fe excited with 514 nm were studied at room temperature and elevated pressure. Up to 16 GPa we find a pressure coefficient for the internal tube of 4.3 cm−1 GPa−1 and for the external tube of 5.5 cm−1 GPa−1. In addition, the tangential band of the external and internal tubes broadens and decreases in amplitude. All findings lead to the conclusion that the outer tube acts as a protection shield for the inner tubes (at least up 16 GPa). Structural phase transitions were not observed in this range of pressure

    Stress-Strain Analysis of Single Cubic Crystals and Its Application to the Ordering of CuAu I : Paper II

    Get PDF
    A stress-strain analysis of single cubic crystals is developed which utilizes the strain data supplied by the x-ray back-reflection divergent beam method. The principal strains and their directions are determined and from the principal strains and the known elastic constants the complete stress-strain configuration is obtained. Thus the maximum magnitude and the direction of the shearing strain on a given set of crystallographic planes are obtained and the set of planes on which the maximum value of the shearing maxima occurs is also determined. From a knowledge of the stress-strain configuration, the sotred elastic energy of the crystal is deduced ; it can be partitioned into two components, that due to shearing strains and that due to a mixture of normal and shearing strains. The conditions under which the principal stress system coincides with the principal strain system are also investigated. Furthermore, a number is constructed that measures the distortion of the crystal in terms of the energy increments associated with the elastic constants. The stress-strain analysis applied to the ordering of a CuAu crystal at 125℃ corroborates quantitatively the qualitative results previously obtained by transmission electron microscopy The dependence of stored elastic energy on annealing time is determined and it is shown that the first maximum and decline are associated with the maximum and decline of coherency strains set up between the ordered CuAu I nuclei and the disordered matrix. Upon increasing the annealing time, twinning occurs to relieve the tetragonality strains introduced by the ordered CuAu I domains. The second maximum is compounded by twinning on certain (110) planes and delayed ordering on other (110) planes of the matrix. The subsequent decline of the stored elastic energy is associated with twinning on all (110) planes. The shearing stress necessary to initiate microtwinning does not exceed 7×10^8 dyn/cm^

    BubR1 promotes Bub3-dependent APC/C inhibition during Spindle Assembly Checkpoint signaling.

    No full text
    The spindle assembly checkpoint (SAC) prevents premature sister chromatid separation during mitosis. Phosphorylation of unattached kinetochores by the Mps1 kinase promotes recruitment of SAC machinery that catalyzes assembly of the SAC effector mitotic checkpoint complex (MCC). The SAC protein Bub3 is a phospho-amino acid adaptor that forms structurally related stable complexes with functionally distinct paralogs named Bub1 and BubR1. A short motif ("loop") of Bub1, but not the equivalent loop of BubR1, enhances binding of Bub3 to kinetochore phospho-targets. Here, we asked whether the BubR1 loop directs Bub3 to different phospho-targets. The BubR1 loop is essential for SAC function and cannot be removed or replaced with the Bub1 loop. BubR1 loop mutants bind Bub3 and are normally incorporated in MCC in vitro but have reduced ability to inhibit the MCC target anaphase-promoting complex (APC/C), suggesting that BubR1:Bub3 recognition and inhibition of APC/C requires phosphorylation. Thus, small sequence differences in Bub1 and BubR1 direct Bub3 to different phosphorylated targets in the SAC signaling cascade
    corecore