8,993 research outputs found
Effect of Our Galaxy's Motion on Weak Lensing Measurements of Shear and Convergence
In this work we investigate the effect on weak-lensing shear and convergence
measurements due to distortions from the Lorentz boost induced by our Galaxy's
motion. While no ellipticity is induced in an image from the Lorentz boost to
first order in beta = v/c, the image is magnified. This affects the inferred
convergence at a 10 per cent level, and is most notable for low multipoles in
the convergence power spectrum C {\kappa}{\kappa} and for surveys with large
sky coverage like LSST and DES. Experiments which image only small fractions of
the sky and convergence power spectrum determinations at l > 5 can safely
neglect the boost effect to first order in beta.Comment: 4 pages, replaced to reflect changes made for publication to MNRA
Analysis of economics of a TV broadcasting satellite for additional nationwide TV programs
The influence of a TV broadcasting satellite, transmitting four additional TV networks was analyzed. It is assumed that the cost of the satellite systems will be financed by the cable TV system operators. The additional TV programs increase income by attracting additional subscribers. Two economic models were established: (1) each local network is regarded as an independent economic unit with individual fees (cost price model) and (2) all networks are part of one public cable TV company with uniform fees (uniform price model). Assumptions are made for penetration as a function of subscription rates. Main results of the study are: the installation of a TV broadcasting satellite improves the economics of CTV-networks in both models; the overall coverage achievable by the uniform price model is significantly higher than that achievable by the cost price model
Switching of the vortex polarity in a magnetic nanodisk by a DC current
We study the dynamics of a vortex state nanodisk due to a dc spin current,
perpendicular to the disk plane. The irreversible switching of the vortex
polarity takes place above some threshold current. The detailed description of
these processes is obtained by spin-lattice simulations.Comment: REVTeX, 4 pages, 3 figure
Controlled vortex core switching in a magnetic nanodisk by a rotating field
The switching process of the vortex core in a Permalloy nanodisk affected by
a rotating magnetic field is studied theoretically. A detailed description of
magnetization dynamics is obtained by micromagnetic simulations.Comment: REVTeX, 5 pages, 5 figure
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