Graphing and communicating compositional data in high dimensions

Visualization of data becomes more challenging as the dimensionality of the data increases, impacting not only the display of the data itself but also the modeling results. This paper discusses common visualization techniques for compositional data. None of them seem to be well suited for changes in compositions that depend on either a metric covariate or a factor. The clr-deviation chart as a chart with a factor or covariate as abscissa and all centered log ratio-transformed component values superimposed on the ordinate axis is then introduced jointly with the clr-component chart. The clr-deviation chart takes advantage of the sum-equals-zero property of clr-transformed compositional data. It has some theoretical and practical advantages over alternatives and one major disadvantage – an arbitrarily scaled ordinate axis; its properties are discussed. The usefulness of the methods are illustrated using an example analyzing the changes of proportions of the different diseases treated by hospitalization over a period of 13 years in Germany

Mapping Itinerant Electrons around Kondo Impurities

We investigate single Fe and Co atoms buried below a Cu(100) surface using low temperature scanning tunneling spectroscopy. By mapping the local density of states of the itinerant electrons at the surface, the Kondo resonance near the Fermi energy is analyzed. Probing bulk impurities in this well-defined scattering geometry allows separating the physics of the Kondo system and the measuring process. The line shape of the Kondo signature shows an oscillatory behavior as a function of depth of the impurity as well as a function of lateral distance. The oscillation period along the different directions reveals that the spectral function of the itinerant electrons is anisotropic.Comment: 5 pages, 4 figures, accepted by Physical Review Letter

"Klassiker zur Jugend": Entwurf zum Diskussionspapier

Das vorliegende Diskussionspapier stellt einige Ausführungen der "Klassiker" Marx, Engels und Lenin zum Thema Jugend bzw. Generation zusammen. Die Ausführungen lassen sich im wesentlichen wie folgt zusammenfassen: (1) Das Problem der Generationsfolge (und folglich der Jugend) ist zwar eine allgemeine Bedingung des menschlichen Lebens, d.h. als rein zeitlich-formaler Aspekt uunabhängig von den konkreten gesellschaftlichen Verhältnissen, ihr Wesen und ihre Wirkung hängt jedoch von den konkreten historischen Verhältnissen ab. (2) Der Kapitalismus als eine spezifisch historische Gesellschaftsformation produziert als Folge der ökonomischen und sozialen Antagonismen einen Generationskonflikt, insofern er jüngere gegen ältere Arbeitnehmer ausspielt (Löhne. Arbeitsplätze usw.) bzw. seine profitorientierte Produktion dazu zwingt. (pmb

UHF and VHF radar observations of thunderstorms

A study of thunderstorms was made in the Summer of 1985 with the 430-MHz and 50-MHz radars at the Arecibo Observatory in Puerto Rico. Both radars use the 300-meter dish, which gives a beam width of less than 2 degrees even at these long wavelengths. Though the radars are steerable, only vertical beams were used in this experiment. The height resolution was 300 and 150 meters for the UHF and VHF, respectively. Lightning echoes, as well as returns from precipitation and clear-air turbulence were detected with both wavelengths. Large increases in the returned power were found to be coincident with increasing downward vertical velocities at UHF, whereas at VHF the total power returned was relatively constant during the life of a storm. This was attributed to the fact that the VHF is more sensitive to scattering from the turbulence-induced inhomogeneities in the refractive index and less sensitive to scatter from precipitation particles. On occasion, the shape of the Doppler spectra was observed to change with the occurrence of a lightning discharge in the pulse volume. Though the total power and mean reflectivity weighted Doppler velocity changed little during these events, the power is Doppler frequency bins near that corresponding to the updraft did increase substantially within a fraction of a second after a discharge was detected in the beam. This suggests some interaction between precipitation and lightning