ALBERT

Notes: Zusammenfassung Erstmals werden bei Säugetieren Vesikulationen der äusseren Lamelle der Kernmembran bei Nieren-und Leberzellen von Mäusen gefunden und diese mit der Proteinsynthese in Verbindung gebracht.

Notes: Abstract A multisite solid solution of the type (A, B) (X, Y) has the four possible components AX, AY, BX, BY. Taking the standard state to be the pure phase at the pressure and temperature of interest, the mixing of these components is shown not to be ideal unless the condition: $$\Delta G^0 = (\mu _{AX}^0 + \mu _{BY}^0 - \mu _{AY}^0 - \mu _{BX}^0 = 0$$ applies. Even for the case in which mixing on each of the individual sublattices is ideal, ΔG 0 contributes terms of the following form to the activity coefficients of the constituent components: $$RT\ln \gamma _{AX} = - X_{B_1 } X_{Y_2 } \Delta G^0$$ (X Ji refers to the atomic fraction of J on sublattice i). The above equation, which assumes complete disorder on (A, B) sites and on (X, Y) sites is extended to the general n-component case. Methods of combining the “cross-site” or reciprocal terms with non-ideal terms for each of the individual sites are also described. The reciprocal terms appear to be significant in many geologically important solid solutions, and clinopyroxene, garnet and spinel solid solutions are all used as examples. Finally, it is shown that the assumption of complete disorder only applies under the condition: $$\Delta G^0 \ll zn_1 RT$$ where z is the number of nearest-neighbour (X, Y) sites around A and n 1 is the number of (A, B) sites in the formula unit. If ΔG 0 is relatively large, then substantial short range oder must occur and the activity coefficient is given by (ignoring individual site terms): $$\gamma _{AX} = \left( {\frac{{1 - X'_{Y_2 } }}{{1 - X_{Y_2 } }}} \right)^{zn_1 }$$ where X′Y2 is the equilibrium atomic fraction of Y atoms surrounding A atoms in the structure. The ordered model may be developed for multicomponent solutions and individual site interactions added, but numerical methods are needed to solve the simultaneous equations involved.

Notes: Abstract Since Mesozoic time, Java and Bali have formed part of an evolving system of island arcs comprising the Sunda arc of Indonesia. The present tectonic setting is relatively simple with subduction occurring at the Java Trench to the south. A north-dipping Benioff seismic zone delineates an underthrust lithospheric slab to depths of approximately 600 km beneath the Java Sea. Quaternary lavas of the ‘normal island arc association’ range from tholeiites to high-K calc-alkaline lavas over Benioff zone depths from 120–250 km, respectively. More abundant calc-alkaline lavas lie between these extremes. High-K alkaline lavas are found over Benioff zone depths in excess of 300 km. Both within and between these groups of rocks there are consistent spatial variations in the observed geochemistry. For approximately 200 rocks, incompatible elements such as K, Rb, Cs, Sr, Ba, light REE, U and Th show an increase in abundance of almost an order of magnitude with increasing depth to the seismic zone. Abundances of compatible elements show little consistent variation and trace elements such as Ni, Co, Cr, and Sc are characteristically depleted except in some of the alkaline lavas. Major element abundances in rocks of the normal island arc association show little variation, except for K and P, which both increase in abundance across the arc and Al, which shows a relative decrease. The major and trace element data are inconsistent with the derivation of the analyzed rocks by partial melting of the crustal component of the subducted lithosphere. On the other hand, low Ni abundances (∼20 ppm) in the basalts suggest that most of the lavas are fractionated and few if any represent primary mantle-derived melts. The spatial variations in the geochemistry of erupted lavas across Java and Bali are best explained by a combination of two processes: melting of a geochemically zoned mantle source and smaller degrees of partial melting of that material at progressively greater depths. Primary tholeiitic magmas could be formed by 20–25% melting at depths of 30–40 km, primary high-K calc-alkaline magmas by 5–15% melting at 40–60 km depth, and primary alkaline magmas by 5% melting at depths of 80–90 km. The geochemical zoning in the mantle, which is also manifested by increasing 87Sr/86Sr ratios in lavas across the arc, is interpreted to result from the addition of a small melt fraction derived from the crustal component of the subducted lithosphere.

Notes: Abstract Duhem's theorem states that the equilibrium position of a system of known bulk composition and size is completely determined by two independent variables. Given these data all other equilibrium parameters can be calculated. The method of calculation is set down in detail for olivine-two pyroxene-spinel assemblages which may serve as models for portions of the upper mantle. To make the calculations, equations for the Gibbs energy of the constituent minerals, olivine, spinel, orthopyroxene and clinopyroxene are formulated. The olivine is treated as an ideal, binary, cationic solid solution. The spinel is treated as a ternary, reciprocal solution between the four end members MgAl2O4, MgCr2O4, FeAl2O4 and FeCr2O4. The pyroxenes are treated as seven-component, simplified reciprocal systems. The eight oxides SiO2, TiO2, Al2O3, Cr2O3, FeO, MgO, CaO and Na2O are thought sufficient for expressing the composition of the model mantle. The paucity and inconsistency of the required thermodynamic data preclude accurate calculations. To illustrate the calculation and to arrive at some highly tentative results, the required free energy data are estimated by combining analytical data from Iherzolite xenoliths with interpretations of experimental data. It seems likely that the Al content of pyroxenes cannot be used as a geobarometer without considering the bulk composition of the assemblage or, equivalently, the composition of the associated spinel phase. Temperature estimates based on the Ca to Ca+Mg ratio in Ca-rich pyroxenes may be approximately correct in the restricted composition range of mantle derived xenoliths.

Notes: Abstract An investigation of the steady-state creep of a Ni3Al.10 at% Fe alloy (γ′) has shown that two creep mechanisms were operative over the temperature range 530 to 930° C. The experimental data at low temperatures (below 680° C) were not consistent with any of the established creep theories. However, the experimental data were in good agreement with a proposed model for cross-slip from octahedral {111} planes on to cube {100} planes in Li2 crystals. Above 680° C, the rate-controlling mechanism, which had an activation energy of 3.27eV atom−1, is considered to be the removal/production of APBs during climb.

Notes: Abstract Slitless VUV spectra of the eclipsed Sun were obtained from a rocket experiment for the first time during the 1970 eclipse. The spatially resolved spectra of a quiescent prominence in the wavelength range 900 Å–2200 Å consist of emission lines from ions formed in the temperature range 3.5 × 104k–3.2 × 105k. The spectral intensities have been interpreted in terms of physical parameters which indicate a transition zone of shell-like layers, the inner the cooler and thinner, the outer the hotter and more extended. The transition zone is about 3 km thick for a model thread of 2000 km in diameter.

Notes: Summary A commercially available sample-injection valve (manual version) has been coupled to the nebulizer of a premixed laminar-flow burner on an atomic absorption spectrometer for metal analysis in volumes of 50–500μl. For 500-μl samples statistical analysis showed an overall coefficient of variation of 1.7% for readings from the peak height facility of a digital read-out unit. In order to obtain reproducible results with 50-μl samples (overall coefficient of variation of 4.3%) it was necessary to use the peak height data obtained from a pen-recorder connected to the digital read-out unit.