ALBERT

Notizen: Abstract This study utilizes an econometric model of equilibrium in the U.S. livestock and feedgrain markets to investigate a number of questions of economic methodology and policy. Both nonlinear consumer demand equations that obey the constraints of neoclassical demand theory and a model of supply are used. This approach allows for the measurement of the effects on consumer welfare of actual government policies. In particular, the model is employed to analyze the welfare effects of an actual policy situation — the sale of U.S. grain to the Soviet Union in the third quarter of 1972.

Notizen: Abstract The recent literature dealing with the redox mechanism of the lead-acid cell positive electrode is reviewed. The basis electrochemistry of lead dioxide in its various polymorphic modifications and states of subdivision is considered in relation to the important aspects of electrode technology of which the major industrial application of the material is the conventional lead-acid cell. The proposed mechanism of the reduction (discharge) of lead dioxide in various acidic solutions are considered in relation to the present state of electrode kinetic theory. The reverse reaction by which lead dioxide is formed and the parasitic intrusion of the self discharge are dealt with as a precursor to the total cyclic process. It is concluded that in a number of respects the mechanisms proposed do not adequately represent the totality of the experimental observations. Such shortcomings are emphasized and extensions to present research are proposed.

Notizen: Abstract The mineralogy and chemistry of picrites from Mauna Loa and Kilauea have been investigated to evaluate, for Hawaiian tholeiitic picrites, the contrasting genetic models which have been proposed for these Mg-rich volcanics, namely products of direct crystallization of high-Mg melts (20–25% MgO) or the result of accumulation of olivine phenocrysts into less Mg-rich melts. Genetic interpretations rely heavily on Mg-Fe partitioning relations between olivines and their picrite hosts. Although the 100 Mg/(Mg + Fe2+) ratios (M) of picrites are wide-ranging (M=73.6–82.9 for Fe2O3/FeO=0.15), with MgO as high as 27.8%, the average 100 Mg/(Mg+Fe) ratios (mg) of the cores of olivine phenocrysts (megacrysts) show only restricted compositional variation (mg=87.2–89.0). Successive olivine generations are progressively more Fe-rich. Olivine/liquid Mg-Fe partitioning data and the Mn and Ni abundances in olivine phenocrysts collectively indicate that they were precipitated by Mg-rich basaltic melts with 12–14% MgO. Spinel compositions range from liquidus magnesiochromites, occurring mainly as inclusions in olivine phenocrysts, to groundmass titanomagnetites which crystallized at nearsolidus temperatures. The Cr2O3 contents and M values of liquidus magnesiochromites suggest that their parent melts were neither Mg-rich picritic (MgO〉20%) nor relatively Mg-poor basaltic types. On MgO variation diagrams (extending from approximately 7% to more than 25% MgO), Mauna Loa and Kilauea picrites and their respective microcrystalline/glassy groundmasses (the major component of quickly-cooled picrites) plot on linear regression lines (‘olivine control lines’). At a given MgO content, Kilauean picrites and tholeiites (M〈75) generally contain more TiO2 FeO t , CaO, K2O and P2O5, and less SiO2 and Na2O than Mauna Loan types. The compositions of the groundmasses in picrites and Mg-rich ol-tholeiites equate closely with those of the Mg-poor tholeiites (7–9% MgO) which dominate the petrology of each shield. Low-pressure closed system differentiation of Hawaiian tholeiitic magmas (10–15% MgO) can yield picritic derivatives which differ, however, from the extrusive picrites by virtue of distinctly higher FeO t contents and correspondingly more Fe-rich olivines and Cr-spinels. The calculated Mg-Fe olivine megacryst-‘liquid’ partition coefficient K D for individual picrites indicate that lowpressure equilibria (K D =0.30–0.34) are defined only by melts with approximately 12–14% MgO (M∼ 71–74). Assessed in conjunction with Ni-MgO modeling, these data indicate that the more Mg-rich picrites (MgO〉 14–15%) are indeed olivine-enriched and do not represent melt compositions. Olivine enrichment resulted from post-eruptive mechanical (flow) differentiation of extruded ‘mushes’ of intratelluric cognate olivine phenocrysts (mg∼88) and tholeiitic melts (M∼60), which are ‘residua’ of the parental magmas (12–14% MgO), following the crystallization of the olivine phenocrysts. The ‘parental’ magmas of both picrite suites were generated by 35–40% melting of relatively Fe-rich spinel lherzolites (mg∼84) containing kaersutitic amphibole as a major primary constituent.

Notizen: Abstract Coral reef sponge populations were surveyed at two spatial scales: different depths and different reef locations across the continental shelf of the central Great Barrier Reef. The surveys were conducted on the forereef slopes of 12 reefs from land-influenced, inner-shelf reefs to those in the oligotrophic waters of the Coral Sea. Few sponges occur in shallow waters and the largest populations are found between 10 and 30 m depth. Sponges are apparently excluded from shallow waters because of excessive turbulence and possibly by high levels of damaging light. Sponge biomass is highest on the innershelf reefs and decreases away from the coast, whereas abundance is generally higher on middle-shelf reefs. There are considerable overlaps in the species composition on middle-, outer-shelf and Coral Sea reefs, but those on inner-shelf reefs are significantly different. The nature and size of sponge populations reflect environmental conditions across the continental shelf. The larger inner-shelf populations probably reflect higher levels of organic and inorganic nutrients and reduced amounts of physical turbulence, whereas sponges on reefs further from shore may be able to resist greater turbulence but appear more sensitive to the effects of fine sediments. These latter populations are smaller, reflecting the reduced availability of organic matter, however, many of these sponges rely on cyanobacterial symbionts to augment nutrition in these clearer, more oligotrophic waters.

Notizen: Abstract Large populations of flattened sponges with cyanobacterial symbionts were observed on the shallow reef-flats of the Flinders Reefs, Coral Sea. Estimates of these populations indicated as many as 60 individuals with a total wet biomass of 1.2 kg per m2 in some areas. Along a metre wide transect across 1.3 km of reef flat the population was estimated at 530 kg wet weight sponge (mean 411 g m-2). The four prominent species had instantaneous P/R ratios between 1.3 and 1.8 at optimum light such that photosynthetic productivity was calculated to provide between 61 and 80% of sponge energy requirements in summer and 48 to 64% in winter. While such sponge beds are a prominent feature of these reefs, they appear to contribute less than 10% of gross reef-flat productivity.

Notizen: Abstract The far infrared spectra of liquid and solid benzene are compared. The benzene was maintained at a temperature of 330 K and the applied pressure varied to alter the state. Liquid benzene is observed to possess a structure resembling that of the solid, close to the melting point.

Notizen: Abstract A summary of the various exercises made in the BCR-framework to improve the quality of analysis of coal is given. The paper presents the way coal samples were prepared and their homogeneity as well as the analytical methods used by various participating laboratories. Special attention is given to the determination of sulphur and trace elements. A considerable improvement of results was obtained upon participation in such BCR-exercises.

Notizen: Abstract The magnetic shear at a point within an active region field configuration can be defined (Hagyard et al., 1984b) as the difference in angle between the observed photospheric transverse field and that of a reference potential field calculated using the observed line-of-sight field as a boundary condition. Using analytic models for non-potential (but force-free) fields representative of preflaring active regions, we calculate the degree of magnetic shear along the magnetic neutral line that such fields would exhibit, as a function of the location and orientation of the active region on the solar disk. We find that, except for regions close to disk center, the position of the inferred neutral line (zero line-of-sight field) is significantly different from the actual neutral line (zero radial field), and that the calculated reference potential field also varies significantly with the position of the region. Thus the inferred degree of shear can vary significantly with the position and orientation of the region, due to (a) straightforward geometric projection effects, (b) the shift of the inferred neutral line relative to its true position, and (c) variations in the reference potential field. The significance of these results for flare prediction is considered.