5,492 research outputs found
Synthesis of finite displacements and displacements in continental margins
The scope of the project is the analysis of displacement-rate fields in the transitional regions between cratonal and oceanic lithospheres over Phanerozoic time (last 700 ma). Associated goals are an improved understanding of range of widths of major displacement zones; the partition of displacement gradients and rotations with position and depth in such zones; the temporal characteristics of such zones-the steadiness, episodicity, and duration of uniform versus nonunifrom fields; and the mechanisms and controls of the establishment and kinematics of displacement zones. The objective is to provide a context of time-averaged kinematics of displacement zones. The initial phase is divided topically among the methodology of measurement and reduction of displacements in the lithosphere and the preliminary analysis from geologic and other data of actual displacement histories from the Cordillera, Appalachians, and southern North America
Higher-order structural organization of the mitochondrial proteome charted by in situ cross-linking mass spectrometry
Mitochondria are densely packed with proteins, of which most are involved physically or more transiently in protein-protein interactions (PPIs). Mitochondria host among others all enzymes of the Krebs cycle and the oxidative phosphorylation (OXPHOS) pathway and are foremost associated with cellular bioenergetics (1, 2). However, mitochondria are also important contributors to apoptotic cell death (3) and contain their own genome (4) indicating that they play additionally an eminent role in processes beyond bioenergetics (5). Despite intense efforts in identifying and characterizing mitochondrial protein complexes by structural biology and proteomics techniques, many PPIs have remained elusive. Several of these (membrane embedded) PPIs are less stable in-vitro hampering their characterization by most contemporary methods in structural biology. Particularly in these cases, cross-linking mass spectrometry (XL-MS) has proven valuable for the in-depth characterization of mitochondrial protein complexes in situ. Here, we highlight experimental strategies for the analysis of proteome-wide protein-protein interactions in mitochondria using XL-MS. We showcase the ability of in situ XL-MS as a tool to map sub-organelle interactions and topologies, and aid in refining structural models of protein complexes. We describe some of the most recent technological advances in XL-MS that may benefit the in situ characterization of PPIs even further, especially when combined with electron microscopy and structural modelling
Acoustic tests of duct-burning turbofan jet noise simulation
The results of a static acoustic and aerodynamic performance, model-scale test program on coannular unsuppressed and multielement fan suppressed nozzle configurations are summarized. The results of the static acoustic tests show a very beneficial interaction effect. When the measured noise levels were compared with the predicted noise levels of two independent but equivalent conical nozzle flow streams, noise reductions for the unsuppressed coannular nozzles were of the order of 10 PNdB; high levels of suppression (8 PNdB) were still maintained even when only a small amount of core stream flow was used. The multielement fan suppressed coannular nozzle tests showed 15 PNdB noise reductions and up to 18 PNdB noise reductions when a treated ejector was added. The static aerodynamic performance tests showed that the unsuppressed coannular plug nozzles obtained gross thrust coefficients of 0.972, with 1.2 to 1.7 percent lower levels for the multielement fan-suppressed coannular flow nozzles. For the first time anywhere, laser velocimeter velocity profile measurements were made on these types of nozzle configurations and with supersonic heated flow conditions. Measurements showed that a very rapid decay in the mean velocity occurs for the nozzle tested
Acoustic tests of duct-burning turbofan jet noise simulation: Comprehensive data report. Volume 2: Model design and aerodynamic test results
The selection procedure is described which was used to arrive at the configurations tested, and the performance characteristics of the test nozzles are given
The background from single electromagnetic subcascades for a stereo system of air Cherenkov telescopes
The MAGIC experiment, a very large Imaging Air Cherenkov Telescope (IACT)
with sensitivity to low energy (E < 100 GeV) VHE gamma rays, has been operated
since 2004. It has been found that the gamma/hadron separation in IACTs becomes
much more difficult below 100 GeV [Albert et al 2008] A system of two large
telescopes may eventually be triggered by hadronic events containing Cherenkov
light from only one electromagnetic subcascade or two gamma subcascades, which
are products of the single pi^0 decay. This is a possible reason for the
deterioration of the experiment's sensitivity below 100 GeV. In this paper a
system of two MAGIC telescopes working in stereoscopic mode is studied using
Monte Carlo simulations. The detected images have similar shapes to that of
primary gamma-rays and they have small sizes (mainly below 400 photoelectrons
(p.e.)) which correspond to an energy of primary gamma-rays below 100 GeV. The
background from single or two electromagnetic subcascdes is concentrated at
energies below 200 GeV. Finally the number of background events is compared to
the number of VHE gamma-ray excess events from the Crab Nebula. The
investigated background survives simple cuts for sizes below 250 p.e. and thus
the experiment's sensitivity deteriorates at lower energies.Comment: 15 pages, 7 figures, published in Journ.of Phys.
Coulomb stability of the 4\pi-periodic Josephson effect of Majorana fermions
The Josephson energy of two superconducting islands containing Majorana
fermions is a 4\pi-periodic function of the superconducting phase difference.
If the islands have a small capacitance, their ground state energy is governed
by the competition of Josephson and charging energies. We calculate this ground
state energy in a ring geometry, as a function of the flux -\Phi- enclosed by
the ring, and show that the dependence on the Aharonov-Bohm phase 2e\Phi/\hbar
remains 4\pi-periodic regardless of the ratio of charging and Josephson
energies - provided that the entire ring is in a topologically nontrivial
state. If part of the ring is topologically trivial, then the charging energy
induces quantum phase slips that restore the usual 2\pi-periodicity.Comment: 4 pages, 4 figures; v2: more references, improved phase-slip formula,
and a discussion of the effect of overlapping Majorana'
Demand-led approaches to drive post-harvest innovation and nutritious RTB products
Roots, Tubers and Bananas (RTB) Strategy Development Workshop Report
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