HUMAN MOTION ANALYSIS AND SYNTHESIS USING GRAPHICAL BIOMECHANICS MODELS IN SPORTS ACTIVITIES

In many applications the study of human movement using a computer is very useful. One such application is the three-dimensional reconstruction of the structure of the human body and its movement using sequences of images and graphic models. For this reconstruction to be accurate and precise the person analyzed and the virtual human (humanoid) must have similar anthropometric characteristics. A process is therefore defined that attempts to adjust the humanoid to the morphology of the person, a process which can be very laborious and subjective if done manually or by selection of points. This article presents a process of semiautomatic matching between person and humanoid. Once this process is carried out we are ready to analyze and represent the movements under study. The study is adapted to specific sports activities. In these cases the adjustment process can be assisted by the computer. At present, it is used in indoor spaces, but its use in outdoor spaces is also intended. The system requires no markers or special clothing to be worn by the athlete or sports participant, and its range of application is therefore very wide. Also very important are its portability into domestic environments using VRML 2.0 and the H-anim standard for specification of virtual humanoids. This advantage is very important because experts can visualize movements on any personal computer with a commercial Internet browser

Anisotropic Atom-Surface Interactions in the Casimir-Polder Regime

The distance-dependence of the anisotropic atom-wall interaction is studied. The central result is the 1/z^6 quadrupolar anisotropy decay in the retarded Casimir-Polder regime. Analysis of the transition region between non-retarded van der Waals regime (in 1/z^3) and Casimir-Polder regime shows that the anisotropy cross-over occurs at very short distances from the surface, on the order of 0.03 Lambda, where Lambda is the atom characteristic wavelength. Possible experimental verifications of this distance dependence are discussed.Comment: 5 pages, 2 figure

Negative-index media for matter-wave optics

We consider the extension of optical meta-materials to matter waves. We show that the generic property of pulsed comoving magnetic fields allows us to fashion the wave-number dependence of the atomic phase shift. It can be used to produce a transient negative group velocity of an atomic wave packet, which results into a negative refraction of the matter wave. Application to slow metastable argon atoms Ar*(3P2) shows that the device is able to operate either as an efficient beam splitter or an atomic meta-lens. Implications of "meta-media" in atom optics are considered.Comment: 4 pages, 4 figures, submitted at PRL 4 November 200

Synchronization of the Frenet-Serret linear system with a chaotic nonlinear system by feedback of states

A synchronization procedure of the generalized type in the sense of Rulkov et al [Phys. Rev. E 51, 980 (1995)] is used to impose a nonlinear Malasoma chaotic motion on the Frenet-Serret system of vectors in the differential geometry of space curves. This could have applications to the mesoscopic motion of biological filamentsComment: 12 pages, 7 figures, accepted at Int. J. Theor. Phy

El status actual de las ecoescuelas: el caso de la provincia de Granada (España)

La preocupación progresiva por la sostenibilidad de las organizaciones sociales representa hoy un factor de calidad de la madurez institucional de un país. Las ecoauditorías ambientales son un ejemplo de buenas prácticas ambientales en los centros educativos. En esta comunicación se analiza la aplicación de estas metodologías al campo de la planificación y gestión escolar. La implantación del Programa a 21 ecoescuelas de la Provincia de Granada se evalúa mediante un diseño de investigación cualitativa con estudio de casos, entrevistas y registros fotográficos. Los resultados se interpretan a través de unas tipologías previas de ecoescuelas -señalando debilidades y fortalezas-, analizando el liderazgo de los coordinadores de los programas y marcando estrategias de futuro

Penning collisions of laser-cooled metastable helium atoms

We present experimental results on the two-body loss rates in a magneto-optical trap of metastable helium atoms. Absolute rates are measured in a systematic way for several laser detunings ranging from -5 to -30 MHz and at different intensities, by monitoring the decay of the trap fluorescence. The dependence of the two-body loss rate coefficient $\beta$ on the excited state ($2^3P_2$) and metastable state ($2^3S_1$) populations is also investigated. From these results we infer a rather uniform rate constant $K_{sp}=(1{\pm}0.4)\times10^{-7}$ cm$^3$/s.Comment: 8 pages, 9 figures, Revte