4,081 research outputs found
Slots in Dielectrically Loaded Waveguide
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116085/1/rds19661131.pd
Statistics and Quantum Chaos
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
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
(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
Gallid herpesvirus 3 SB-1 strain as a recombinant viral vector for poultry vaccination
Live herpesvirus-vectored vaccines are widely used in veterinary medicine to protect against many infectious diseases. In poultry, three strains of herpesvirus vaccines are used against Marek’s disease (MD). However, of these, only the herpesvirus of turkeys (HVT) has been successfully developed and used as a recombinant vaccine vector to induce protection against other avian viral diseases such as infectious bursal disease (IBD), Newcastle disease (ND) or avian influenza (AI). Although effective when administered individually, recombinant HVT vectors have limitations when combined in multivalent vaccines. Thus there is a need for developing additional viral vectors that could be combined with HVT in inducing protection against multiple avian diseases in multivalent vaccines. Gallid herpesvirus 3 (GaHV3) strain SB-1 is widely used by the poultry industry as bivalent vaccine in combination with HVT to exploit synergistic effects against MD. Here, we report the development and application of SB-1 as a vaccine vector to express the VP2 capsid antigen of IBD virus. A VP2 expression cassette was introduced into the SB-1 genome at three intergenic locations (UL3/UL4, UL10/UL11 and UL21/UL22) using recombineering methods on the full-length pSB-1 infectious clone of the virus. We show that the recombinant SB-1 vectors expressing VP2 induced neutralising antibody responses at levels comparable to that of commercial HVT-based VAXXITEKHVT+IBD vaccine. Birds vaccinated with the experimental recombinant SB-1 vaccine were protected against clinical disease after challenge with the very virulent UK661 IBDV isolate, demonstrating its value as an efficient viral vector for developing multivalent vaccines against avian diseases
Atg6 is required for multiple vesicle trafficking pathways and hematopoiesis in Drosophila
Atg6 (beclin 1 in mammals) is a core component of the Vps34 complex that is required for autophagy. Beclin 1 (Becn1) functions as a tumor suppressor, and Becn1(+/-) tumors in mice possess elevated cell stress and p62 levels, altered NF-kappaB signaling and genome instability. The tumor suppressor function of Becn1 has been attributed to its role in autophagy, and the potential functions of Atg6/Becn1 in other vesicle trafficking pathways for tumor development have not been considered. Here, we generate Atg6 mutant Drosophila and demonstrate that Atg6 is essential for autophagy, endocytosis and protein secretion. By contrast, the core autophagy gene Atg1 is required for autophagy and protein secretion, but it is not required for endocytosis. Unlike null mutants of other core autophagy genes, all Atg6 mutant animals possess blood cell masses. Atg6 mutants have enlarged lymph glands (the hematopoietic organ in Drosophila), possess elevated blood cell numbers, and the formation of melanotic blood cell masses in these mutants is not suppressed by mutations in either p62 or NFkappaB genes. Thus, like mammals, altered Atg6 function in flies causes hematopoietic abnormalities and lethality, and our data indicate that this is due to defects in multiple membrane trafficking processes
Nematic Films and Radially Anisotropic Delaunay Surfaces
We develop a theory of axisymmetric surfaces minimizing a combination of
surface tension and nematic elastic energies which may be suitable for
describing simple film and bubble shapes. As a function of the elastic constant
and the applied tension on the bubbles, we find the analogues of the unduloid,
sphere, and nodoid in addition to other new surfaces.Comment: 15 pages, 18 figure
Modeling the series of (n x 2) Si-rich reconstructions of beta-SiC(001): a prospective atomic wire?
We perform ab initio plane wave supercell density functional calculations on
three candidate models of the (3 x 2) reconstruction of the beta-SiC(001)
surface. We find that the two-adlayer asymmetric-dimer model (TAADM) is
unambiguously favored for all reasonable values of Si chemical potential. We
then use structures derived from the TAADM parent to model the silicon lines
that are observed when the (3 x 2) reconstruction is annealed (the (n x 2)
series of reconstructions), using a tight-binding method. We find that as we
increase n, and so separate the lines, a structural transition occurs in which
the top addimer of the line flattens. We also find that associated with the
separation of the lines is a large decrease in the HOMO-LUMO gap, and that the
HOMO state becomes quasi-one-dimensional. These properties are qualititatively
and quantitatively different from the electronic properties of the original (3
x 2) reconstruction.Comment: 22 pages, including 6 EPS figure
Fredholm determinants and the statistics of charge transport
Using operator algebraic methods we show that the moment generating function
of charge transport in a system with infinitely many non-interacting Fermions
is given by a determinant of a certain operator in the one-particle Hilbert
space. The formula is equivalent to a formula of Levitov and Lesovik in the
finite dimensional case and may be viewed as its regularized form in general.
Our result embodies two tenets often realized in mesoscopic physics, namely,
that the transport properties are essentially independent of the length of the
leads and of the depth of the Fermi sea.Comment: 30 pages, 2 figures, reference added, credit amende
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