37,189 research outputs found
Systematic derivation of a rotationally covariant extension of the 2-dimensional Newell-Whitehead-Segel equation
An extension of the Newell-Whitehead-Segel amplitude equation covariant under
abritrary rotations is derived systematically by the renormalization group
method.Comment: 8 pages, to appear in Phys. Rev. Letters, March 18, 199
Mechanism of margination in confined flows of blood and other multicomponent suspensions
Flowing blood displays a phenomenon called margination, in which leukocytes
and platelets are preferentially found near blood vessel walls, while
erythrocytes are depleted from these regions. Here margination is investigated
using direct hydrodynamic simulations of a binary suspension of stiff (s) and
floppy (f) capsules, as well as a stochastic model that incorporates the key
particle transport mechanisms in suspensions -- wall-induced hydrodynamic
migration and shear-induced pair collisions. The stochastic model allows the
relative importance of these two mechanisms to be directly evaluated and
thereby indicates that margination, at least in the dilute case, is largely due
to the differential dynamics of homogeneous (e.g. s-s) and heterogeneous (s-f)
collisionsComment: 5 Pages, 4 figure
Some Pattern Recognition Challenges in Data-Intensive Astronomy
We review some of the recent developments and challenges posed by the data
analysis in modern digital sky surveys, which are representative of the
information-rich astronomy in the context of Virtual Observatory. Illustrative
examples include the problems of an automated star-galaxy classification in
complex and heterogeneous panoramic imaging data sets, and an automated,
iterative, dynamical classification of transient events detected in synoptic
sky surveys. These problems offer good opportunities for productive
collaborations between astronomers and applied computer scientists and
statisticians, and are representative of the kind of challenges now present in
all data-intensive fields. We discuss briefly some emergent types of scalable
scientific data analysis systems with a broad applicability.Comment: 8 pages, compressed pdf file, figures downgraded in quality in order
to match the arXiv size limi
Measurement of the differential cross-section of B + meson production in pp collisions at âs=7 TeV at ATLAS
The production cross-section of B + mesons is measured as a function of transverse momentum p T and rapidity y in proton-proton collisions at centre-of-mass energy sâ=7 TeV, using 2.4 fbâ1 of data recorded with the ATLAS detector at the Large Hadron Collider. The differential production cross-sections, determined in the range 9 GeV < p T < 120 GeV and |y| < 2.25, are compared to next-to-leading-order theoretical predictions
A sub-product construction of Poincare-Einstein metrics
Given any two Einstein (pseudo-)metrics, with scalar curvatures suitably
related, we give an explicit construction of a Poincar\'e-Einstein
(pseudo-)metric with conformal infinity the conformal class of the product of
the initial metrics. We show that these metrics are equivalent to ambient
metrics for the given conformal structure. The ambient metrics have holonomy
that agrees with the conformal holonomy. In the generic case the ambient metric
arises directly as a product of the metric cones over the original Einstein
spaces. In general the conformal infinity of the Poincare metrics we construct
is not Einstein, and so this describes a class of non-conformally Einstein
metrics for which the (Fefferman-Graham) obstruction tensor vanishes.Comment: 23 pages Minor correction to section 5. References update
Dynamics of isolated-photon plus jet production in pp collisions at âs=7 TeV with the ATLAS detector
The dynamics of isolated-photon plus jet production in pp collisions at a centre-of-mass energy of 7 TeV has been studied with the ATLAS detector at the LHC using an integrated luminosity of 37 pbâ1. Measurements of isolated-photon plus jet bin-averaged cross sections are presented as functions of photon transverse energy, jet transverse momentum and jet rapidity. In addition, the bin-averaged cross sections as functions of the difference between the azimuthal angles of the photon and the jet, the photonâjet invariant mass and the scattering angle in the photonâjet centre-of-mass frame have been measured. Next-to-leading-order QCD calculations are compared to the measurements and provide a good description of the data, except for the case of the azimuthal opening angle
Measurement of jet shapes in top-quark pair events at âs =7 TeV using the ATLAS detector
A measurement of jet shapes in top-quark pair events using 1.8 fbâ1 of âs=7 TeV pp collision data recorded by the ATLAS detector at the LHC is presented. Samples of top-quark pair events are selected in both the single-lepton and dilepton final states. The differential and integrated shapes of the jets initiated by bottom-quarks from the top-quark decays are compared with those of the jets originated by light-quarks from the hadronic W-boson decays WâqqÂŻâČ in the single-lepton channel. The light-quark jets are found to have a narrower distribution of the momentum flow inside the jet area than b-quark jets
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