The paper deals with the construction of images from visibilities acquired using aperture synthesis instruments: Fourier synthesis, deconvolution, and spectral interpolation/extrapolation. Its intended application is to specific situations in which the imaged object possesses two superimposed components: (i) an extended component together with (ii) a set of point sources. It is also specificall...

We describe a simple test of the spatial uniformity of an ensemble of discrete events. Given an estimate for the point source luminosity function and an instrumental point spread function (PSF), a robust upper bound on the fractional point source contribution to a diffuse signal can be found. We verify with Monte Carlo tests that the statistic is superior to the two-point correlation function f...

We investigate a class of reactive advection-diffusion problems motivated by an ecological mixing process. We use analytical and numerical methods to determine reaction rates between two initially distinct scalar point masses that are separated from one another by a third (nonreactive) scalar. The scalars are stirred by a single two-dimensional vortex in a variety of geometrical configurations....

Let Ω ⊂ RN be a bounded domain. We introduce a distance ‖A− B‖ between two n-tuples of point sources A = (a1, ..., an), B = (b1, ...., bn) ∈ Ω and we establish upper and lower estimates between ‖A−B‖ and a norm of Pn j=1 δaj − Pn j=1 δbj . Next we will apply the estimates to the following two inverse problems and prove best possible conditional stability estimates: (i) inverse problem of determ...

OBJECTIVES To compare methods for defining the population at risk from a point source of air pollution. A major challenge for environmental epidemiology lies in correctly identifying populations at risk from exposure to environmental pollutants. The complexity of today's environment makes it essential that the methods chosen are accurate and sensitive. METHODS Environmental and mathematical m...

Consider a diffusion field induced by a finite number of localized and instantaneous sources. In this paper, we study the problem of estimating these sources (including their intensities, spatial locations, and activation time) from the spatiotemporal samples taken by a network of spatially distributed sensors. We propose two estimation algorithms, depending on whether the activation time of th...

Current multicast routing protocols have not been designed for mobile nodes and especially roaming sources. Using the remote subscription as basis, we develop a new approach based on a new entity called Mobility-aware Rendezvous Point (MRP) to hide the mobility of a mobile multicast source from the main multicast delivery tree and offer an optimal routing. The key idea of this work is to make t...

General formulae are derived for the orientation of phototropic organisms in a field illuminated by two point-sources of light in the same horizontal plane. It is shown that formulae previously found may all be derived as special cases of these general equations.

The localization of fluorescent microspheres is often employed for drift correction and image registration in single molecule microscopy, and is commonly carried out by fitting a point spread function to the image of the given microsphere. The mismatch between the point spread function and the image of the microsphere, however, calls into question the suitability of this localization approach. ...

Noncommutative gravity in three dimensions with no cosmological constant is reviewed. We find a solution which describes the presence of a torsional source. 1 What does ‘noncommutative’ mean? Please see [1] for a review of noncommutative field theory, if you want to study more. Consider noncommutative coordinates, for example [x, y ] = i θ , (1) where θ is a real constant. Then the ‘uncertainty...