3,179 research outputs found

    Hidden treasure: Financial models for retrofits

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    This paper examines financial models capable of enabling the adoption of fuel-efficiency and alternative fuel technologies that profitably reduce the fuel use and resulting greenhouse gas emissions (GHG) of the shipping industry

    Statistics and Quantum Chaos

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    We use multi-time correlation functions of quantum systems to construct random variables with statistical properties that reflect the degree of complexity of the underlying quantum dynamics.Comment: 12 pages, LateX, no figures, restructured versio

    Reconstruction and thermal stability of the cubic SiC(001) surfaces

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    The (001) surfaces of cubic SiC were investigated with ab-initio molecular dynamics simulations. We show that C-terminated surfaces can have different c(2x2) and p(2x1) reconstructions, depending on preparation conditions and thermal treatment, and we suggest experimental probes to identify the various reconstructed geometries. Furthermore we show that Si-terminated surfaces exhibit a p(2x1) reconstruction at T=0, whereas above room temperature they oscillate between a dimer row and an ideal geometry below 500 K, and sample several patterns including a c(4x2) above 500 K.Comment: 12 pages, RevTeX, figures 1 and 2 available in gif form at http://irrmawww.epfl.ch/fg/sic/fig1.gif and http://irrmawww.epfl.ch/fg/sic/fig2.gi

    The Index of (White) Noises and their Product Systems

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    (See detailed abstract in the article.) We single out the correct class of spatial product systems (and the spatial endomorphism semigroups with which the product systems are associated) that allows the most far reaching analogy in their classifiaction when compared with Arveson systems. The main differences are that mere existence of a unit is not it sufficient: The unit must be CENTRAL. And the tensor product under which the index is additive is not available for product systems of Hilbert modules. It must be replaced by a new product that even for Arveson systems need not coincide with the tensor product

    The Role of Bilayer Tilt Difference in Equilibrium Membrane Shapes

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    Lipid bilayer membranes below their main transition have two tilt order parameters, corresponding to the two monolayers. These two tilts may be strongly coupled to membrane shape but only weakly coupled to each other. We discuss some implications of this observation for rippled and saddle phases, bilayer tubules, and bicontinuous phases. Tilt difference introduces a length scale into the elastic theory of tilted fluid membranes. It can drive an instability of the flat phase; it also provides a simple mechanism for the spontaneous breaking of inversion symmetry seen in some recent experiments.Comment: Latex file; .ps available at http://dept.physics.upenn.edu/~nelson/saddle.p

    Structure and Function of Human DnaJ Homologue Subfamily A Member 1 (DNAJA1) and Its Relationship to Pancreatic Cancer

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    Pancreatic cancer has a dismal 5 year survival rate of 5.5% that has not been improved over the past 25 years despite an enormous amount of effort. Thus, there is an urgent need to identify truly novel yet druggable protein targets for drug discovery. The human protein DnaJ homologue subfamily A member 1 (DNAJA1) was previously shown to be downregulated 5- fold in pancreatic cancer cells and has been targeted as a biomarker for pancreatic cancer, but little is known about the specific biological function for DNAJA1 or the other members of the DnaJ family encoded in the human genome. Our results suggest the overexpression of DNAJA1 suppresses the stress response capabilities of the oncogenic transcription factor, c-Jun, and results in the diminution of cell survival. DNAJA1 likely activates a DnaK protein by forming a complex that suppresses the JNK pathway, the hyperphosphorylation of c-Jun, and the anti-apoptosis state found in pancreatic cancer cells. A high-quality nuclear magnetic resonance solution structure of the J-domain of DNAJA1 combined with a bioinformatics analysis and a ligand affinity screen identifies a potential DnaK binding site, which is also predicted to overlap with an inhibitory binding site, suggesting DNAJA1 activity is highly regulated

    The existence problem for dynamics of dissipative systems in quantum probability

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    Motivated by existence problems for dissipative systems arising naturally in lattice models from quantum statistical mechanics, we consider the following C∗C^{\ast}-algebraic setting: A given hermitian dissipative mapping δ\delta is densely defined in a unital C∗C^{\ast}-algebra A\mathfrak{A}. The identity element in A{\frak A} is also in the domain of δ\delta. Completely dissipative maps δ\delta are defined by the requirement that the induced maps, (aij)→(δ(aij))(a_{ij})\to (\delta (a_{ij})), are dissipative on the nn by nn complex matrices over A{\frak A} for all nn. We establish the existence of different types of maximal extensions of completely dissipative maps. If the enveloping von Neumann algebra of A{\frak A} is injective, we show the existence of an extension of δ\delta which is the infinitesimal generator of a quantum dynamical semigroup of completely positive maps in the von Neumann algebra. If δ\delta is a given well-behaved *-derivation, then we show that each of the maps δ\delta and −δ-\delta is completely dissipative.Comment: 24 pages, LaTeX/REVTeX v. 4.0, submitted to J. Math. Phys.; PACS 02., 02.10.Hh, 02.30.Tb, 03.65.-w, 05.30.-
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