The choice of idols from a social psychological perspective

The study of adolescents’ idols has an over 100-year tradition. The meta-analysis of Teigen, Normann, Bjorkheim and Helland (2000) showed that idols, which are commonly understood as role models, changed over the last century which is attributed to changes in the social context. The present paper argues that Social Identity Theory (Tajfel & Turner, 1979, 1986) offers an appropriate theoretical framework to conceptualize social context by hypothesising a functional relationship between idols and identity management strategies moderated by the status position of the adolescent’s group s/he belongs to. The hypothesised functional relationship was tested in two studies with white and black adolescent South Africans. The results of the two studies supported our assumptions that the functional relationship between idols and identity management strategies is indeed moderated by status position. The results also indicate that Social Identity Theory seems to be an appropriate theoretical framework when social context is particularly conceptualised as social change

Investigation of unconventional reconstruction and electronic properties on the Na2IrO3 surface

Na2IrO3 is an intriguing material for which spin-orbit coupling plays a key role. Theoretical predictions, so far unverified, have been made that the surface of Na2IrO3 should exhibit a clear signature of the quantum spin Hall effect. We studied the surface of Na2IrO3 using scanning tunneling microscopy and density-functional theory calculations. We observed atomic level resolution of the surface and two types of terminations with different surface periodicity and Na content. By comparing bias-dependent experimental topographic images to simulated images, we determined the detailed atomistic structure of both observed surfaces. One of these reveals a strong relaxation to the surface of Na atoms from the subsurface region two atomic layers below. Such dramatic structural changes at the surface cast doubt on any prediction of surface properties based on bulk electronic structure. Indeed, using spatially resolved tunneling spectroscopy we found no indication of the predicted quantum spin Hall behavior

Raíces pequeñas del dosel del pinabete (Picea abies): distribución e influencia en el crecimiento de hayas

The horizontal and vertical distribution of live fine roots (diameter < 2 mm) of overstory Norway spruce [Picea abies (L.) Karst.] and their influence on diameter and height growth of underplanted beech (Fagus sylvatica L.) and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) saplings were studied on experimental plots in the Solling Mountains (Germany). The aims of this study were to investigate how overstory fine root density varies with stand density, and how it influences growth of the underplanted saplings to changes in belowground resources availability in connection with simultaneously changing light availability. Most fine roots were concentrated in the humus layer (more than 45%) and in the top mineral soil (0-5 cm, about 15%). Fine root biomass increases with overstory basal area and decreases with rising distance from the nearest overstory tree, reaching about zero within ca. 8 m distance. Over the whole two-year study period, light availability alone was the decisive factor for growth of the beech saplings (5 resp. 6 years of age) while growth of the Douglas-fir saplings in the first study year (6 years of age) was additionally affected by a shortage of belowground resources due to root competition in a season with less than average rainfall. This species-specific response of underplanted saplings to changes in above and belowground resources is of silvicultural importance for the establishment of a mixed stand beneath a mature canopy: the more sensitive Douglasfir should be planted on the central parts of openings with little or none belowground competition while the less sensitive beech can be placed below the denser parts of the overstory.Se estudia la distribución horizontal y vertical de las raíces finas (diámetro < 2 mm) vivas del dosel de pinabete y su influencia en el diámetro y el crecimiento en altura de hayas plantadas y en brinzales de abeto Douglas en parcelas experimentales en las montes de Solling (Alemania). Los objetivos de este estudio es analizar cómo la densidad de raíces finas del dosel varía con la densidad del rodal, y cómo influye en el crecimiento de los árboles jóvenes del subpiso debido a los cambios en la disponibilidad de recursos en el suelo, en relación con el cambio al mismo tiempo en la disponibilidad de luz. Las raíces más finas se concentra en la capa de humus (más del 45%) y en la parte mineral superior del suelo (0-5 cm, aproximadamente el 15%). La biomasa de raíces finas aumenta con el área bisimétrica del dosel y disminuye con la distancia creciente al árbol más cercano del dosel, hasta llegar a cero dentro de ca. 8 m de distancia. Durante el periodo de estudio de dos años, la disponibilidad de luz era el único factor decisivo para el crecimiento de los plantones de haya (5 resp. 6 años de edad) mientras que el crecimiento de las plántulas de pino de Douglas en el primer año de estudio (6 años de edad) se vio afectado adicionalmente por la escasez de recursos en el suelo debido a la competencia de las raíces en una temporada con una precipitación menor del promedio. Esta respuesta especie-especifica de los árboles del subpiso a los cambios en los recursos por encima y por debajo del suelo es de importancia silvícola para la creación de una masa mixta bajo un dosel maduro: la especie más sensible, pino de Douglas, se debe plantar en las partes centrales de las aberturas con poca o ninguna competencia bajo tierra, mientras que el haya, menos sensible, se puede colocar debajo de las partes más densas del estrato superior

New Molecular Collisional Interaction Effect in Low-Energy Sputtering

Y. Yao, Z. Hargitai, M. Albert, R. G. Albridge, A. V. Barnes, J. M. Gilligan, B. Pratt Ferguson, G. Lüpke, V. D. Gordon (currently with UT Austin), and N. H. Tolk are with the Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 -- J. C. Tully is with the Department of Physics and Department of Chemistry, Yale University, New Haven, Connecticut 06520 -- G. Betz and W. Husinsky are with the Institut für Allgemeine Physik, Technische Universität Wien, A-1040 Vienna, AustriaAn unexpected pronounced enhancement is observed in sputtering yields per atom for N2+ compared to N+ from a polycrystalline gold target. This effect is seen when the kinetic energy per projectile atom is below 500 eV and increases as projectile energy decreases to near-threshold energies. Enhancements for O2+ over O+ begin at even lower kinetic energies below 100 eV per atom. This new molecular interaction effect may be explained qualitatively by invoking a simple energy transfer model which involves the vibrational frequency of the molecule and the collisional interaction time. [S0031-9007(98)06668-X]Chemistr

Gene expression analysis of ELF-MF exposed human monocytes indicating the involvement of the alternative activation pathway

This study focused on the cell activating capacity of extremely low frequency magnetic fields (ELF-MF) on human umbilical cord blood-derived monocytes. Our results confirm the previous findings of cell activating capacity of ELF-MF (1.0 mT) in human monocytes, which was detected as an increased ROS release. Furthermore, gene expression profiling (whole-genome cDNA array Human Unigene RZPD-2) was performed to achieve a comprehensive view of involved genes during the cell activation process after 45 min ELF-MF exposure. Our results indicate the alteration of 986 genes involved in metabolism, cellular physiological processes, signal transduction and immune response. Significant regulations could be analyzed for 5 genes (expression >2- or <0.5-fold): IL15RA (Interleukin 15 receptor, alpha chain), EPS15R (Epidermal growth factor receptor pathway substrate 15 - like 1), DNMT3A (Hypothetical protein MGC16121), DNMT3A (DNA (cytosine-5) methyltransferase 3 alpha), and one gene with no match to known genes, DKFZP586J1624. Real-time RT-PCR analysis of the kinetic of the expression of IL15RA, and IL10RA during 45 min ELF-MF exposure indicates the regulation of cell activation via the alternative pathway, whereas the delayed gene expression of FOS, IL2RA and the melatonin synthesizing enzyme HIOMT suggests the suppression of inflammatory processes. Accordingly, we suggest that ELF-MF activates human monocytes via the alternative pathway

Evidence for two coupled subsystems in the superconducting state of La2-xSrxCuO4

We used a pump-probe technique to measure the transient change of optical reflectivity of both La2-xSrxCuO4, of various dopings, and slightly underdoped YBa2Cu3O7-x and NdBa2Cu3O7-x thin films. For the La2-xSrxCuO4 films, our data demonstrate the coexistence, in the superconducting state, of two coupled subsystems with different relaxation times and different contributions to the optical reflectivity. One subsystem is associated with the superconducting phase. By contrast. the data from YBa2Cu3O7-x, and NdBa2Cu3O7-x shows that the coupling between the two subsystems is weak or absent