An explanation is proposed for the fact that pp–waves superpose linearly when they propagate parallely, while they interact nonlinearly, scatter and form singularities or Cauchy horizons if they are antiparallel. Parallel pp–waves do interact, but a generalized gravitoelectric force is exactly cancelled by a gravitomagnetic force. In an analogy, the interaction of light beams in linearized gene...

We study the superconducting vortex states induced by the interplay of long-range Pearl repulsion and short-range intervortex attraction using Langevin dynamics simulations. We show that at low temperatures the vortices form an ordered Abrikosov lattice both in low and high fields. The vortices show distinctive modulated structures at intermediate fields depending on the effective intervortex a...

Henrich and Boyd (2002) were the first to propose a formal model of the role of attraction in cultural evolution. Th ey came to the surprising conclusion that, when both attraction and selection are at work, final outcomes are determined by selection alone. Th is result is based on a determistic view of cultural attraction, different from the probabilistic view introduced in Sperber (1996). We ...

What causes same-sex attraction? Or, more broadly, what controls sex/gender-based attraction? Over the years there have been numerous theories, but more recently scientists have focused on the biology and, more specifically, the neurobiology of gender-based attraction. This article takes the reader through a critical review of the current literature related to sex/gender-based attraction. In ex...

Long-branch attraction is a well-known source of systematic error that can mislead phylogenetic methods; it is frequently invoked post hoc, upon recovering a different tree from the one expected based on prior evidence. We demonstrate that methods that do not force the data onto a single tree, such as spectral analysis, Neighbor-Net, and consensus networks, can be used to detect conflicting sig...

There are several methods for approximating the multiple zeros of a nonlinear function when the multiplicity is known. The methods are classified by the order, informational efficiency and efficiency index. Here we consider other criteria, namely the basin of attraction of the method and its dependence on the order. We discuss all known methods of orders two to four and present the basin of att...

Do people who work hard also tend to play hard? We tested this hypothesis using an online questionnaire-based study of a large volunteer sample of university undergraduate students. Participants responded to questions designed to detect variation in attraction to accomplishment/fame (or ‘work’) and attraction to leisure (or ‘play’). Additional questions were asked, for use in posthoc explorator...

Applicant attraction was examined in the context of Web-based recruitment. A person-organization (P-O) fit framework was adopted to examine how the provision of feedback to individuals regarding their potential P-O fit with an organization related to attraction. Objective and subjective P-O fit, agreement with fit feedback, and self-esteem also were examined in relation to attraction. Results o...

A learning method using domains of attraction in three-layered neural networks is proposed. The method is a combination of output error minimization learning with maximization learning of domains of attraction in one-layered perceptrons. To simplify the structure of the network, a successive learning technique is employed for hidden units. Domains of attraction in the network is derived by rest...

The bouncing ball apparatus exhibits a rich variety of nonlinear dynamical behavior and is one of the simplest mechanical systems to produce chaotic behavior. A computer control system is designed for output calibration, state determination, system identification and control of the bouncing ball apparatus designed by Launch Point Technologies. Two experimental methods are used to determine the ...