We propose differential holography as a method to overcome the long-standing forward-scattering problem in photoelectron holography and related techniques for the three-dimensional imaging of atoms. Atomic images reconstructed from experimental and theoretical Cu 3p holograms from Cu(001) demonstrate that this method suppresses strong forward-scattering effects so as to yield more accurate thre...

Mailing address: Marcelo Luiz Campos Vieira • Rua Cardoso de Melo, 463/21 04548-002 São Paulo, SP Brazil E-mail: [email protected] Manuscript received January 09, 2007; revised manuscript received January 01, 2007; accepted March 13, 2007. The use of three-dimensional echocardiography for the analysis of cardiac structures allows the viewing of planes that make the anatomic identification m...

We study the role played by bilinguals in the competition between two languages and in the formation of a bilingual community. To this aim we introduce a simple three-state model that combines the Minett-Wang model, in which the bilinguals do not affect directly the probability of transition of an individual from monolingualism to bilingualism, and the Baggs-Freedman model, in which such a tran...

We focused on how repeat collaborations in projects for inventions affect performance. Repeat collaborations have two contradictory aspects. A positive aspect is team development or experience, and a negative aspect is team degeneration or decline. Since both contradicting phenomena are observed, inventors have a dilemma as to whether they should keep collaborating in a team or not. The dilemma...

The results of experiments in developing a method for extracting three-dimensional information from a scene by means of a polarimetric passive imaging sensor are summarized. This sensor provides a full Stokes vector at each sensor pixel location from which degree and angle of linear polarization are computed. The angle of linear polarization provides the azimuth angle of the surface normal vect...

This article addresses the current state of the art of technology in three-dimensional echocardiography as it applies to transducer design, beam forming, display, and quantification. Because three-dimensional echocardiography encompasses many technical and clinical areas, this article reviews its strengths and limitations and concludes with an analysis of what to use when.

represent in renewal theory the elapsed lifetimes of the "item in use" at time t. The limiting behavior of Y% as t—* °° has been extensively studied; if ju = £(X¿) < oo, Yt itself has a limiting distribution [8; 2] while if p= oo, the generalized arc-sine laws emerge as the possible limit distributions of Yt/t [2; 6]. It may be remarked that Yt forms a Markov process with right-continuous path ...

By international standards the economy of South Africa is extremely energy intensive with only a few countries having higher intensities. SA’s primary energy use per unit of GDP is amongst the highest in the world The high energy and electricity intensity of the economy partly reflects SA’s resource endowments (in particular the abundance of coal) but is also a function of the historical under-...