13,503 research outputs found
Non-perturbative decay of Non-Abelian hair
We construct a solution of Heterotic supergravity which interpolates between
two different AdS geometries corresponding to the
near-horizon limits of two 5-dimensional black holes, only one of which has
non-Abelian hair. This solution can be used to estimate the amplitude of
probability of the non-perturbative decay of the gauge 5-brane responsible for
the non-Abelian hair into eight solitonic 5-branes by evaluating its Euclidean
action. The Wick rotation of this solution poses several problems which we
argue can be overcome by using a non-extremal off-shell (NEOS) deformation of
the solution. This NEOS field configuration can be Wick rotated straight away
and its Euclidean action can be computed for any value of the deformation
parameter. The Euclidean result can then be anti-Wick-rotated and its extremal
limit gives the Euclidean action of the original solution, which turns out to
be one half of the difference between the entropies of the 5-dimensional black
holes.Comment: Few typos corrected. Two references and a footnote added. Version to
be published in JHE
Square root kalman filter with contaminated observations
The algorithm of square root Kalman filtering for the case of contaminated observations is described in the paper. This algorithm is suitable for the parallel computer implementation allowing to treat dynamic linear systems with large number of state variables in a robust recursive way
EGF receptor trafficking: consequences for signaling and cancer
The ligand-stimulated epidermal growth factor receptor (EGFR) has been extensively studied in the analysis of molecular mechanisms regulating endocytic traffic and the role of that traffic in signal transduction. Although such studies have largely focused on mitogenic signaling and dysregulated traffic in tumorigenesis, there is growing interest in the potential role of EGFR traffic in cell survival and the consequent response to cancer therapy. Here we review recent advances in our understanding of molecular mechanisms regulating ligand-stimulated EGFR activation, internalization, and post-endocytic sorting. The role of EGFR overexpression/mutation and new modulators of EGFR traffic in cancer and the response to cancer therapeutics are also discussed. Finally, we speculate on the relationship between EGFR traffic and cell survival
Autonomous Systems as Legal Agents: Directly by the Recognition of Personhood or Indirectly by the Alchemy of Algorithmic Entities
The clinical manifestations of platelet dense (δ) granule defects are easy bruising, as well as epistaxis and bleeding after delivery, tooth extractions and surgical procedures. The observed symptoms may be explained either by a decreased number of granules or by a defect in the uptake/release of granule contents. We have developed a method to study platelet dense granule storage and release. The uptake of the fluorescent marker, mepacrine, into the platelet dense granule was measured using flow cytometry. The platelet population was identified by the size and binding of a phycoerythrin-conjugated antibody against GPIb. Cells within the discrimination frame were analysed for green (mepacrine) fluorescence. Both resting platelets and platelets previously stimulated with collagen and the thrombin receptor agonist peptide SFLLRN was analysed for mepacrine uptake. By subtracting the value for mepacrine uptake after stimulation from the value for uptake without stimulation for each individual, the platelet dense granule release capacity could be estimated. Whole blood samples from 22 healthy individuals were analysed. Mepacrine incubation without previous stimulation gave mean fluorescence intensity (MFI) values of 83±6 (mean ± 1 SD, range 69–91). The difference in MFI between resting and stimulated platelets was 28±7 (range 17–40). Six members of a family, of whom one had a known δ-storage pool disease, were analysed. The two members (mother and son) who had prolonged bleeding times also had MFI values disparate from the normal population in this analysis. The values of one daughter with mild bleeding problems but a normal bleeding time were in the lower part of the reference interval
Drude in D major
We study holographic momentum relaxation in the limit of a large number of
spacetime dimensions D. For an axion model we find that momentum conservation
is restored as D becomes large. To compensate we scale the strength of the
sources with D so that momentum is relaxed even at infinite D. We analytically
obtain the quasi-normal modes which control electric and heat transport, and
give their frequencies in a 1/D expansion. We also obtain the AC thermal
conductivity as an expansion in 1/D, which at leading order takes Drude form.
To order 1/D our analytical result provides a reasonable approximation to the
AC conductivity even at D=4, establishing large D as a practical method in this
context. As a further application, we discuss the signature of the transition
from coherent to incoherent behaviour known to exist in the system for finite
D.Comment: 19 pages, 2 figure
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