Popular and official appraisals of natural resources: some evidence from Australia

European occupation of the Australian continent from 1788 onwards has provided evidence of both officially designed land settlement schemes and independent privately organized activities. Both settlement processes required the resources of the continent to be appraised in some detail. Over the years those appraisals, of the arid and semi-arid lands in particular, can be seen to have varied not only within but also between government and the private sector. The variations have reflected not only the changing technological context but also the changing philosophical context of resource management. The resultant changing roles of the various colonial, state and Commonwealth governments have been parallelled by changing popular concepts of what constitute resources, how they should be managed and by whom. The conflicts which resulted and which still occur pose wider questions of resource management for not only these arid and semi-arid lands.     

Re-examination of the crystal structure of weberite

Summary The crystal structure of weberite, Na₂MgAlF₇, was redetermined from 3-dim. X-ray data and refined by least squares methods in space groupImma to a conventional reliability factorR=0.036. Mg and Al have octahedral 6-coordination. Two crystallographically independent kinds of Na atoms form different NaF₈-polyhedra with the F atoms at the corners of a flattened hexagonal bipyramid and of a square prism, respectively.

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Neubestimmung der Kristallstruktur des Weberits

Zusammenfassung Die Kristallstruktur des Weberits, Na₂MgAlF₇, wurde aus 3-dim. Röntgendaten neu hestimmt und mit der Methode der kleinsten Quadrate in RaumgruppeImma auf den konventionellen ZuverlässigkeitsfaktorR=0,036 verfeinert. Mg und Al haben oktaedrische 6-Koordination. Zwei kristallographisch unabhängige Arten von Na-Atomen bilden mit den F-Atomen zwei verschiedene NaF₈-Polyeder; in einem sitzen die F-Atome an den Ecken einer abgeflachten hexagonalen Bipyramide, im anderen an den Ecken eines quadratischen Prismas.

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With 2 Figures     

Tritium-Verteilung,Durchmischungsverhältnisse und Altersstruktur der Wassermasse im Vierwaldstättersee

Tritium of thermonuclear origin was measured in four different depth profiles in the Lake of Lucerne. Its concentration distribution yielded information on the mixing within the water mass under observation. A simple model was established for approximating the age structure of the water layers.     

Grundlagen zur numerischen Behandlung des allgemeinen Zweischichtenproblems in der Geoelektrik

Zusammenfassung Es wird das allgemeine Zweischichtenproblem in der Geoelektrik neu bearbeitet, und im besonderen werden zwei umfassende Folgen von Spezialfällen einer numerischen Behandlung zugänglich gemacht.

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Summary A contribution to a convenient numerical calculation of the field of a point source of current situated on the earth's surface above an inclined plane is given.