46,962 research outputs found
A measure for the chirality of triangles
A measure for the description of the chirality of triangles is introduced.
The measure is zero for triangles with at least one mirror axe, i.e.
equilateral or isosceles triangles, and positive or negative for scalane, i.e.
left or right handed triangles, respectively
Optimized Data Representation for Interactive Multiview Navigation
In contrary to traditional media streaming services where a unique media
content is delivered to different users, interactive multiview navigation
applications enable users to choose their own viewpoints and freely navigate in
a 3-D scene. The interactivity brings new challenges in addition to the
classical rate-distortion trade-off, which considers only the compression
performance and viewing quality. On the one hand, interactivity necessitates
sufficient viewpoints for richer navigation; on the other hand, it requires to
provide low bandwidth and delay costs for smooth navigation during view
transitions. In this paper, we formally describe the novel trade-offs posed by
the navigation interactivity and classical rate-distortion criterion. Based on
an original formulation, we look for the optimal design of the data
representation by introducing novel rate and distortion models and practical
solving algorithms. Experiments show that the proposed data representation
method outperforms the baseline solution by providing lower resource
consumptions and higher visual quality in all navigation configurations, which
certainly confirms the potential of the proposed data representation in
practical interactive navigation systems
Statistical properties at the spectrum edge of the QCD Dirac operator
The statistical properties of the spectrum of the staggered Dirac operator in
an SU(2) lattice gauge theory are analyzed both in the bulk of the spectrum and
at the spectrum edge. Two commonly used statistics, the number variance and the
spectral rigidity, are investigated. While the spectral fluctuations at the
edge are suppressed to the same extent as in the bulk, the spectra are more
rigid at the edge. To study this effect, we introduce a microscopic unfolding
procedure to separate the variation of the microscopic spectral density from
the fluctuations. For the unfolded data, the number variance shows oscillations
of the same kind as before unfolding, and the average spectral rigidity becomes
larger than the one in the bulk. In addition, the short-range statistics at the
origin is studied. The lattice data are compared to predictions of chiral
random-matrix theory, and agreement with the chiral Gaussian Symplectic
Ensemble is found.Comment: 12 pages, 22 figures, minor typos corrected, version to appear in
Euro. Phys. J.
Discovery of a two-dimensional topological insulator in SiTe
Two-dimensional (2D) topological insulators (TIs), a new state of quantum
matter, are promising for achieving the low-power-consuming electronic devices
owning to the remarkable robustness of their conducting edge states against
backscattering. Currently, the major challenge to further studies and possible
applications is the lack of suitable materials, which should be with high
feasibility of fabrication and sizeable nontrivial gaps. Here, we demonstrate
through first-principles calculations that SiTe 2D crystal is a promising 2D TI
with a sizeable nontrivial gap of 0.220 eV. This material is dynamically and
thermally stable. Most importantly, it could be easily exfoliated from its
three-dimensional superlattice due to the weakly bonded layered structure.
Moreover, strain engineering can effectively control its nontrivial gap and
even induce a topological phase transition. Our results provide a realistic
candidate for experimental explorations and potential applications of 2D TIs
Emanations of Dark Matter: Muon Anomalous Magnetic Moment, Radiative Neutrino Mass, and Novel Leptogenesis at the TeV Scale
The evidence for dark matter signals a new class of particles at the TeV
scale, which may manifest themselves indirectly through loop effects. In a
simple model we show that these loop effects may be responsible for the
enhanced muon anomalous magnetic moment, for the neutrino mass, as well as for
leptogenesis in a novel way. This scenario can be verified at LHC experiments.Comment: 12 pages, 3 figure
Comparing location decisions of domestic and foreign auto supplier plants
Plant locations in the U.S. auto industry have been moving southward for some time now. This paper utilizes a comprehensive dataset of the U.S. auto industry and focuses on plant location decisions of auto supplier plants that were opened less than 15 years ago in the U.S. We find that agglomeration continues to matter: suppliers want to be close to each other as well as to their assembly plant customers. We also find evidence of differences in location factors for domestic and foreign suppliers. Foreign suppliers exhibit a stronger preference to be near highways, other foreign suppliers and foreign assembly plants. That helps explain the different location patterns observed for these two groups within the auto region.Automobile industry and trade ; Automobiles - Prices ; Industrial location
Pathogenicity of anti-ADAMTS13 autoantibodies in acquired thrombotic thrombocytopenic purpura.
BACKGROUND: Acquired thrombotic thrombocytopenic purpura (TTP) is an autoimmune disease in which anti-ADAMTS13 autoantibodies cause severe enzyme deficiency. ADAMTS13 deficiency causes the loss of regulation of von Willebrand factor multimeric size and platelet-tethering function, which results in the formation of disseminated microvascular platelet microthrombi. Precisely how anti-ADAMTS13 autoantibodies, or antibody subsets, cause ADAMTS13 deficiency (ADAMTS13 activity generally <Â 10%) has not been formally investigated. METHODS: We analysed 92 acquired TTP episodes at presentation, through treatment and remission/relapse using epitope mapping and functional analyses to understand the pathogenic mechanisms of anti-ADAMTS13 IgG. RESULTS: 89/92 of TTP episodes had IgG recognising the ADAMTS13 N-terminal domains. The central spacer domain was the only N-terminal antigenic target detected. 38/92 TTP episodes had autoantibodies recognising the N-terminal domains alone; 54/92 TTP episodes also had antibodies against the ADAMTS13 C-terminal domains (TSP2-8 and/or CUB domains). Changes in autoantibody specificity were detected in 9/16 patients at relapse, suggesting a continued development of the disease. Functional analyses on IgG from 43 patients revealed inhibitory IgG were limited to anti-spacer domain antibodies. However, 15/43 patients had autoantibodies with no detectable inhibitory action and as many as 32/43 patients had autoantibodies with inhibitory function that was insufficient to account for the severe deficiency state, suggesting that in many patients there is an alternative pathogenic mechanism. We therefore analysed plasma ADAMTS13 antigen levels in 91 acquired TTP presentation samples. We demonstrated markedly reduced ADAMTS13 antigen levels in all presentation samples, median 6% normal (range 0-47%), with 84/91 patients having <Â 25% ADAMTS13 antigen. ADAMTS13 antigen in the lowest quartile at first presentation was associated with increased mortality (odds ratio 5.7). CONCLUSIONS: Anti-spacer domain autoantibodies are the major inhibitory antibodies in acquired TTP. However, depletion of ADAMTS13 antigen (rather than enzyme inhibition) is a dominant pathogenic mechanism. ADAMTS13 antigen levels at presentation have prognostic significance. Taken together, our results provide new insights into the pathophysiology of acquired TTP
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