378 research outputs found
Thermo-visual feature fusion for object tracking using multiple spatiogram trackers
In this paper, we propose a framework that can efficiently combine features for robust tracking based on fusing the outputs of multiple spatiogram trackers. This is achieved without the exponential increase in storage and processing that other multimodal tracking approaches suffer from. The framework allows the features to be split arbitrarily between the trackers, as well as providing the flexibility to add, remove or dynamically weight features. We derive a mean-shift type algorithm for the framework that allows efficient object tracking with very low computational overhead. We especially target the fusion of thermal infrared and visible spectrum features as the most useful features for automated surveillance applications. Results are shown on multimodal video sequences clearly illustrating the benefits of combining multiple features using our framework
A QCD Analysis of the Mass Structure of the Nucleon
{}From the deep-inelastic momentum sum rule and the trace anomaly of the
energy-momentum tensor, I derive a separation of the nucleon mass into the
contributions of the quark and gluon kinetic and potential energies, the quark
masses, and the trace anomaly.Comment: 9 pages, MIT-CTP #2368, revtex with 1 tabl
Exponentiation of the Drell-Yan cross section near partonic threshold in the DIS and MSbar schemes
It has been observed that in the DIS scheme the refactorization of the
Drell-Yan cross section leading to exponentiation of threshold logarithms can
also be used to organize a class of constant terms, most of which arise from
the ratio of the timelike Sudakov form factor to its spacelike counterpart. We
extend this exponentiation to include all constant terms, and demonstrate how a
similar organization may be achieved in the MSbar scheme. We study the
relevance of these exponentiations in a two-loop analysis.Comment: 20 pages, JHEP style, no figure
Molecular systematics of swifts of the genus Chaetura (Aves: Apodiformes: Apodidae)
Phylogenetic relationships among swifts of the morphologically conservative genus Chaetura were studied using mitochondrial and nuclear DNA sequences. Taxon sampling included all species and 21 of 30 taxa (species and subspecies) within Chaetura. Our results indicate that Chaetura is monophyletic and support the division of the genus into the two subgenera previously identified using plumage characters. However, our genetic data, when considered in combination with phenotypic data, appear to be at odds with the current classification of some species of Chaetura. We recommend that C. viridipennis, currently generally treated as specifically distinct from C. chapmani, be returned to its former status as C. chapmani viridipennis, and that C. andrei, now generally regarded as synonymous with C. vauxi aphanes, again be recognized as a valid species. Widespread Neotropical species C. spinicaudus is paraphyletic with respect to more range-restricted species C. fumosa, C. egregia, and C. martinica. Geographically structured genetic variation within some other species of Chaetura, especially notable in C. cinereiventris, suggests that future study may lead to recognition of additional species in this genus. Biogeographic analysis indicated that Chaetura originated in South America and identified several dispersal events to Middle and North America following the formation of the Isthmus of Panama
Exact Hypersurface-Homogeneous Solutions in Cosmology and Astrophysics
A framework is introduced which explains the existence and similarities of
most exact solutions of the Einstein equations with a wide range of sources for
the class of hypersurface-homogeneous spacetimes which admit a Hamiltonian
formulation. This class includes the spatially homogeneous cosmological models
and the astrophysically interesting static spherically symmetric models as well
as the stationary cylindrically symmetric models. The framework involves
methods for finding and exploiting hidden symmetries and invariant submanifolds
of the Hamiltonian formulation of the field equations. It unifies, simplifies
and extends most known work on hypersurface-homogeneous exact solutions. It is
shown that the same framework is also relevant to gravitational theories with a
similar structure, like Brans-Dicke or higher-dimensional theories.Comment: 41 pages, REVTEX/LaTeX 2.09 file (don't use LaTeX2e !!!) Accepted for
publication in Phys. Rev.
Anisotropic optical properties of single-crystal GdBa2Cu3O7-delta
The optical spectrum of reduced-T(c) GdBa2Cu3O7-delta has been measured for polarizations parallel and perpendicular to the ab plane. The sample was an oxygen-deficient single crystal with a large face containing the c axis. The polarized reflectance from this face was measured from 20-300 K in the spectral region from 30-3000 cm-1, with 300 K data to 30 000 cm-1. Kramers-Kronig analysis was used to determine the spectral dependence of the ab and the c components of the dielectric tensor. The optical properties are strongly anisotropic. The ab-plane response resembles that of other reduced-T(c) materials whereas the c axis, in contrast, shows only the presence of several phonons. There is a complete absence of charge carrier response along c above and below T(c). This observation allows us to set an upper limit to the free-carrier spectral weight for transport perpendicular to the CuO2 planes
Intron with transgenic marker (InTraM) facilitates high-throughput screening of endogenous gene reporter lines
The generation and maintenance of genome edited zebrafish lines is typically labor intensive due to the lack of an easy visual readâout for the modification. To facilitate this process, we have developed a novel method that relies on the inclusion of an artificial intron with a transgenic marker (InTraM) within the knockâin sequence of interest, which upon splicing produces a transcript with a precise and seamless modification. We have demonstrated this technology by replacing the stop codon of the zebrafish fli1a gene with a transcriptional activator KALTA4, using an InTraM that enables red fluorescent protein expression in the heart
Effect of different standing poses on whole body volume acquisition by three-dimensional photonic scanning
The present study compared whole body volumes obtained by three-dimensional (3D) photonic scanning of two different poses and discussed its effect on body composition estimation. Pose A with large angles of shoulder abduction and feet separated and Pose B with shoulders abducted slightly, the elbows extended and heels together. 16 male and 13 female participants were scanned twice in each pose using a 3D scanner. The mean of whole body volume and the mean of body composition obtained with Pose B was corrected by a regression equation and compared with the results obtained from Pose A. After correction, the whole body volumes acquired with these two poses were similar [limit of agreement = (-0.71 l,0.71 l)] but the body compositions obtained with Pose A and Pose B were different [limit of agreement = (-4.4%, 4.4%)]. The results indicated that scanning using either pose gives reliable estimations for whole body volume and body composition. The whole body volume obtained from different poses can be adjusted using the regression equation but small volumetric differences translate into much more substantial differences in body fat percentage. Hence, it is recommended to use the same scanning pose consistently when monitoring individuals longitudinally
Near-Maximal Mixing of Scalar Gluonium and Quark Mesons: A Gaussian Sum-Rule Analysis
Gaussian QCD sum-rules are ideally suited to the study of mixed states of
gluonium (glueballs) and quark () mesons because of their capability
to resolve widely-separated states of comparable strength. The analysis of the
Gaussian QCD sum-rules (GSRs) for all possible two-point correlation functions
of gluonic and non-strange () quark scalar () currents is
discussed. For the non-diagonal sum-rule of gluonic and currents we
show that perturbative and gluon condensate contributions are chirally
suppressed compared to non-perturbative effects of the quark condensate, mixed
condensate, and instantons, implying that the mixing of quark mesons and
gluonium is of non-perturbative origin. The independent predictions of the
masses and relative coupling strengths from the non-diagonal and the two
diagonal GSRs are remarkably consistent with a scenario of two states with
masses of approximately 1 GeV and 1.4 GeV that couple to significant mixtures
of quark and gluonic currents. The mixing is nearly maximal with the heavier
mixed state having a slightly larger coupling to gluonic currents than the
lighter state.Comment: Updated version contains extended analysis and revised analysis
methods. 21 pages, 14 figure
Laws of large numbers for eigenvectors and eigenvalues associated to random subspaces in a tensor product
Given two positive integers and and a parameter , we
choose at random a vector subspace of dimension . We show that the
set of -tuples of singular values of all unit vectors in fills
asymptotically (as tends to infinity) a deterministic convex set
that we describe using a new norm in .
Our proof relies on free probability, random matrix theory, complex analysis
and matrix analysis techniques. The main result result comes together with a
law of large numbers for the singular value decomposition of the eigenvectors
corresponding to large eigenvalues of a random truncation of a matrix with high
eigenvalue degeneracy.Comment: v3 changes: minor typographic improvements; accepted versio
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