introduction: the main goal of spect imaging is to determine activity distribution inside the organs of the body. however, due to photon attenuation, it is almost impossible to do a quantitative study. in this paper, we suggest a mathematical relationship between activity distribution and its corresponding projections using a transfer matrix. monte carlo simulation was used to find a precise tr...

Local studies have shown that the distribution of red knots Calidris canutus across intertidal mudflats is consistent with the predictions of an ideal distribution, but not a free distribution. Here, we scale up the study of feeding distributions to their entire wintering area in western Europe. Densities of red knots were compared among seven wintering sites in The Netherlands, UK and France, ...

The uniformly minimum variance unbiased estimator (UMVUE) and the maximum likelihood estimator (MLE) are derived for samples from uniform distribution in the presence of outliers, where outliers are generated from generalized uniform distribution (GUD), when one parameter of the GUD is known. In this case it has been shown that UMVUE is better than MLE. When both the parameters are unknown then...

This paper analyzes the DV-HOP algorithm which is a range-free localization algorithm. We improve this algorithm by revising the hop-size. In our method, uniform distribution model and secondary reference nodes are introduced to localize the unknown nodes. In addition, the hop-size of the nearest hop is used during the estimation of the distances between the beacon nodes to the unknown nodes. S...

In this article we revisit the much-studied behavior of self-assembled aggregates of gold colloidal particles. In the literature, the electrostatic interactions, van der Waals interactions, and the change in free energy due to ligand-ligand or ligand-solvent interactions are mainly considered to be the dominating factors in determining the characteristics of the gold aggregates. However, our li...

A highly polydisperse granular gas is modeled by a continuous distribution of particle sizes, a , giving rise to a corresponding continuous temperature profile, T(a) , which we compute approximately, generalizing previous results for binary or multicomponent mixtures. If the system is driven, it evolves toward a stationary temperature profile, which is discussed for several driving mechanisms i...

We introduce a lattice model able to describe damage and yielding in heterogeneous materials ranging from brittle to ductile ones. Ductile fracture surfaces, obtained when the system breaks once the strain is completely localized, are shown to correspond to minimum energy surfaces. The similarity of the resulting fracture paths to the limits of brittle fracture or minimum energy surfaces is qua...