Nickel nanoparticles were found to promote the Wittig-type olefination of primary alcohols with phosphorus ylides. The latter can be prepared from the corresponding phosphonium salts with nBuLi or in situ generated with lithium metal. The methodology is especially efficient for…

A cubication procedure of the nonlinear differential equation for conservative nonlinear oscillators is analyzed and discussed. This scheme is based on the Chebyshev series expansion of the restoring force and this allows us to approximate the original nonlinear differential equation…

Multi-agent systems are composed of autonomous entities that cooperate forming emergent behaviors. The communication between agents is sometimes unpredictable, and the resulting communication patterns can become crucial in their performance. This paper presents a metrics suite for evaluating the communication…

This article reviews the state of art of the research concerning the biomechanics of blocking in volleyball. Since it is fundamental to link the "reality of the game" (what happens in the field) with laboratory simulations, the logic procedure to…

We argue that ethical leadership must be in line with corporate governance in general and of the Chief Executive Officer (CEO) who must be the starting point for the rest of the organisational members to have an ethical guideline to…

When aberrations are small, it is possible to use wave aberration variance to obtain the position of the best image plane in both conventional and holographic optical systems. However, when aberrations increase, this measurement is not sufficient and it does…

Kogelnik's coupled-wave theory has provided a well-established basis for understanding how light propagates inside a volume hologram, giving an accurate approximation of the diffraction efficiency in this type of hologram. In this paper we elaborate on some aspects of the…

Bleached holograms are one of the most interesting techniques used to produce phase holograms of high quality on photographic emulsions. Of particular interest is the method of fixation-free rehalogenating bleaching. In this paper we will study the influence of the…

Bleaching is one of the most widely used techniques in the production of phase holograms of high quality on photographic emulsion, particularly in rehalogenating techniques without a fixation step. These techniques were very well understood when Agfa 8E75 HD emulsion…

As a way of forecasting future evolution of inequalities in disease burden and mortality, trends in preventive health behaviours by social class were examined. Using the Spanish National Hearth Survey from 1987 to 1997 the evolution of the Health Practices…