Substrate effects on surface magetetism of Fe/W(110) from first principles

Surface magnetic properties of the pseudomorphic Fe(110) monolayer on a W(110) substrate are investigated from first principles as a function of the substrate thickness (up to eight layers). Analyzing the magnetocrystalline anisotropy energies, we find stable (with respect to the number of substrate layers) in-plane easy and hard axes of magnetization along the [1[overline 1]0] and [001] directions, respectively, reaching a value in good agreement with experiment for thick substrates. Additionally, the changes to the magnetic spin moments and the density of the Fe d states are analyzed with respect to the number of substrate layers as well as with respect to the direction of magnetization. With respect to the number of W(110) substrate layers beneath the Fe(110) surface, we find that the first four substrate layers have a large influence on the electronic and magnetic properties of the surface. Beyond the fourth layer, the substrate has only marginal influence on the surface properties.Comment: 8 Pages, 3 Figures, 3 Table

From Homing Behavior to Cognitive Mapping - Integration of Egocentric Pose Relations and Allocentric Landmark Information in a Graph Model

This thesis describes a behavior based approach to the problem of simultaneous localization and mapping ( SLAM ). The complex behavior of exploring an unknown environment is based on a combination of three local navigation strategies: obstacle avoidance, path integration, and scene based homing. :p: In this context the role of metric pose information is discussed. In the proposed system pose information is used to overcome several shortcomings of topological navigation, especially the problem of spatial aliasing. The spatial memory of the agent is modeled as a graph, which is embedded into the three dimensional pose space. In order to achieve global consistency a modified multidimensional scaling algorithm ( MDS ) is used. The proposed system differs from recent robotic systems in several ways. First, pose estimates are derived only between known places, i.e. there is no explicit knowledge about the location of single landmarks. Second, all pose relations are derived from odometry. Third, globally consistent position estimates are calculated separately from globally consistent heading estimates

El Sexo en los Apotelesmatica de Tolomeo

The sexual polarity, belonging to a world-wide web of oppositions, concerns the heavenly bodies and regions themselves as well as their influence on entire peoples and idividuals on earth. Ptolemy depends on Babylonian and Hellenistic astrology, Pythagorean numerology, Aristotelian ethics and Greek mythology. His detailed enumeration of all thinkable cases shows a rigorous schematism of both contents and syntax that considers all possible varieties of sexual comportment and depravation.La polaridad sexual, que pertenece a una red universal de oposiciones, concierne tanto a los cuerpos y regiones del cielo como a su influencia sobre pueblos enteros e individuos sobre la tierra. Tolomeo depende de la astrología babilonia y helenística, de la numerología pitagórica, de la ética aristotélica y de la mitología griega. Su detallada enumeración de todos los casos imaginables muestra un riguroso esquematismo de ambos contenidos y una sintaxis que considera todas las variedades posibles del comportamiento y la depravación sexuales

Zukunftsmusik: Telephonie und Sphärenharmonie in einer Karikatur des Jahres 1877

In 1877 an unknown ironic caricaturist prizes the invention of telephony by the harmony of the spheres, representing the planets as musicians playing various instruments that are connected by cables and poles with the earth and its three continents. In a coherent system, the drawing combines manifold ideas of ancient and contemporary astronomy and technique up to the music of Richard Wagner, which was perceived at that time as epoch-making as telephony.Ein unbekannter Karikaturist des Jahres 1877 feiert ironisch die Erfindung der Telephonie mit einem Bild der Sphärenharmonie, wobei die Planeten verschiedene Musikinstrumente spielen, die mit Kabeln und Telephonmasten an die Erde und ihre drei Kontinente angeschlossen sind. Die Zeichnung kombiniert in einem schlüssigen System mannigfache Ideen der antiken und zeitgenössischen Astronomie und Technik, bis hin zu der Musik Richard Wagners, die seinerzeit als ebenso bahnbrechend empfunden wurde wie die Telephonie