12,643 research outputs found
Conatraints on from Prompt Photon plus Jet Production at HERA-
The utility of prompt photon plus associated jet production for constraining
the size and shape of the polarized gluon density of the proton is
examined at GeV, appropriate for the proposed HERA-
polarized collider experiment. The calculation is performed at
next-to-leading order (O()) in QCD. The reliability of the
predictions are examined in some detail.Comment: 16 pages, 3 figure
Global Research Report – South and East Asia
Global Research Report – South and East Asia by Jonathan Adams, David Pendlebury, Gordon Rogers & Martin Szomszor. Published by Institute for Scientific Information, Web of Science Group
The almost alternating diagrams of the trivial knot
Bankwitz characterized an alternating diagram representing the trivial knot.
A non-alternating diagram is called almost alternating if one crossing change
makes the diagram alternating. We characterize an almost alternaing diagram
representing the trivial knot. As a corollary we determine an unknotting number
one alternating knot with a property that the unknotting operation can be done
on its alternating diagram.Comment: 29 pages, 18 figure
The Beginning of the End of the Anthropic Principle
We argue that if string theory as an approach to the fundamental laws of
physics is correct, then there is almost no room for anthropic arguments in
cosmology. The quark and lepton masses and interaction strengths are
determined.Comment: 12 page
Gaussian Process Kernels for Pattern Discovery and Extrapolation
Gaussian processes are rich distributions over functions, which provide a Bayesian nonparametric approach to smoothing and interpolation. We introduce simple closed form kernels that can be used with Gaussian processes to discover patterns and enable extrapolation. These kernels are derived by modeling a spectral density – the Fourier transform of a kernel – with a Gaussian mixture. The proposed kernels support a broad class of stationary covariances, but Gaussian process inference remains simple and analytic. We demonstrate the proposed kernels by discovering patterns and performing long range extrapolation on synthetic examples, as well as atmospheric CO2 trends and airline passenger data. We also show that it is possible to reconstruct several popular standard covariances within our framework.Engineering and Applied Science
Engineering polymer informatics: Towards the computer-aided design of polymers
The computer-aided design of polymers is one of the holy grails of modern chemical
informatics and of significant interest for a number of communities in polymer
science. The paper outlines a vision for the in silico design of polymers and presents
an information model for polymers based on modern semantic web technologies, thus
laying the foundations for achieving the vision
Strong Anisotropy in Liquid Water upon Librational Excitation using Terahertz Laser Fields
Tracking the excitation of water molecules in the homogeneous liquid is
challenging due to the ultrafast dissipation of rotational excitation energy
through the hydrogen-bonded network. Here we demonstrate strong transient
anisotropy of liquid water through librational excitation using single-color
pump-probe experiments at 12.3 THz. We deduce a third order response of chi^3
exceeding previously reported values in the optical range by three orders of
magnitude. Using a theory that replaces the nonlinear response with a material
response property amenable to molecular dynamics simulation, we show that the
rotationally damped motion of water molecules in the librational band is
resonantly driven at this frequency, which could explain the enhancement of the
anisotropy in the liquid by the external Terahertz field. By addition of salt
(MgSO4), the hydration water is instead dominated by the local electric field
of the ions, resulting in reduction of water molecules that can be dynamically
perturbed by THz pulses
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