134 results for Journal article, 1950

  • Frequency-sensitive switching circuit

    Earnshaw, J.B. (1956)

    Journal article
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. A frequency-sensitive switching circuit is described which automatically selects between two ranges of an otherwise conventional frequency meter by switching the leak resistor of the integrating circuit. The basis of the unit is a diode pump integrator operated as a nonlinear device to obtain maximum sensitivity. The sensitivity is such that the "on-off" backlash of the switching relay corresponds to less than 1% of the switching frequency.

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  • Mycorrhiza and phosphorus uptake

    Morrison, T. M. (1957)

    Journal article
    Landcare Research

    Reprinted from Nature, Vol. 179, pp. 907-908, May 4, 1957.

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  • Determination of manganese in milk

    Healy, W. Bernard (1958)

    Journal article
    Landcare Research

    The low level of manganese - 0.02 to 0.06 γ per ml. - in the presence of a high level of calcium - up to 0.1 % - makes the determination of manganese in milk difficult because of turbidity interference by calcium sulfate. This paper presents a method for the determination of manganese in 100-ml. samples of milk. The bulk of the calcium is removed as calcium phosphate in the presence of HEEDTA with little or no loss of manganese and the permanganate density is measured in 5-cm. light path cells requiring only 6 ml. of solution, using a Beckman DU spectrophotometer.

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  • The chloride content of rain-water collected in the Wellington province

    Blakemore, L. C. (1953)

    Journal article
    Landcare Research

    Chloride determinations have been made at monthly intervals on rain-water samples collected at nine stations in the Wellington Province. The results show that the annual deposit of chloride, expressed as sodium chloride, ranged from 54 lb. per acre at inland stations to 346 lb. per acre at coastal stations.

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  • Plant pathogenicity studies with non-sporing fungi from tussock-grassland soils

    Morrison, T. M.; Ross, D. J.; Thornton, R. H. (1959)

    Journal article
    Landcare Research

    Some strains of an unnamed Rhizoctonia sp., Rhizoctonia solani, and a Sterile Mycelium, isolated from tussock grassland soils, show no pathogenic activity against lettuce, radish, wheat, potatoes, or pines. The fungi do not form mycorrhizal associations with Pinus radiata.

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  • The soils of the Navua Plains and their chemical status

    Fox, J. P.; Twyford, I. T. (1954)

    Journal article
    Landcare Research

    Reprinted from Fiji Agricultural Journal, Vol. 25, Nos. 1-2, March 1954.

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  • Allophane in volcanic ash soils

    Birrell, K. S.; Fieldes, M. (1952)

    Journal article
    Landcare Research

    Extract from the Journal of Soil Science, Vol. 3, no. 2, 1952, pp. 156-166.

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  • A soil fungus trap

    Thornton, R. H. (1958)

    Journal article
    Landcare Research

    Reprinted from Nature, Vol. 182, p. 1690, Dec. 13, 1958.

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  • Pleistocene shorelines at Porirua Harbour, near Wellington, New Zealand

    Leamy, M. L. (1958)

    Journal article
    Landcare Research

    This paper deals only with ancient shoreline features found near the northern and eastern shorelines of the Pauatahanui Inlet of Porirua Harbour. Correspondence of the heights of these features with heights of Pleistocene shorelines overseas is remarkably close. Although Porirua Harbour lies in a tectonically unstable environment, a hypothesis advanced by Cotton (1952) suggests that the Harbour itself may have largely escaped the effects of recent differential earth movements. Pleistocene shorelines could well be preserved in such a locality, and terraces are correlated by height with the (post-glacial) thermal maximum, Late Monastirian, Main Monastirian, Tyrrhenian, Milazzian, and Sicilian shorelines of other regions.

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  • Source of error in determination of boron by Chromotype-B

    Healy, W. B. (1951)

    Journal article
    Landcare Research

    Reprinted from Analytical Chemistry, Vol. 23, Page 1716, November 1951.

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  • Biological studies of some tussock-grassland soils. IV, Bacteria

    Stout, J. D. (1958)

    Journal article
    Landcare Research

    A quantitative and qualitative study of the bacteria of three tussock-grassland soils has been made to determine the relative influence of vegetation and soil type on the flora. Greatest numbers of bacteria tend to occur in the topsoil rather than in the subsoil and in the spring rather than the summer or autumn. Of the five main taxonomic groups recognised, one (the Achromobacteriaceae) is considered to be chiefly derived from the leaf flora while the distribution of the aerogenic fermenters (Enterobacteriaceae and Aeromonas) is considered to be related to the relative organic content and the extent of the rooting systems in the three soils. The predominant flora consists chiefly of pseudomonads and is very similar in all three soils. Generally, the flora consists of strongly oxidative and proteolytic strains, psychrophilic or mesophilic rather than thermophilic, requiring readily available sources of energy but not requiring growth factors and capable of using ammonium as a sole source of nitrogen. There is a positive correlation between the saccharolytic and proteolytic activities of the strains and denitrification. Generally, it is considered that the activity of the flora is controlled primarily by the condition of the plant cover and particularly by root activity. Neither moisture nor temperature appear to be serious limiting factors.

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  • Corrosion of cement-asbestos and concrete pipes in some New Zealand soils

    Penhale, H. R. (1957)

    Journal article
    Landcare Research

    Cement-asbestos and concrete pipes from five localities were examined for corrosion after exposure to soils for periods up to 10 years. Corrosion measurements and soil and ground-water analyses are given and field conditions are described.

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  • Rhizoctonia in natural grassland soils

    Thornton, R. H. (1956)

    Journal article
    Landcare Research

    Reprinted from Nature, Vol. 177, pp. 230-231, Feb. 4, 1956.

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  • Excystment of Frontonia depressa (Stokes) Penard

    Stout, J. D. (1956)

    Journal article
    Landcare Research

    Frontonia depressa (Stokes) Penard is an edaphic species characterized by formation of cysts. There is no dedifferentiation of the ciliate when encysted, and all organelles, except the body cilia and buccal apparatus, are clearly visible. Excystment is dependent upon the building up of hydrostatic pressure by the contractile vacuole. Activation is not always followed by excystment, which takes some hours.

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  • Biological studies of some tussock-grassland soils. III, Yeasts

    di Menna, M. E. (1958)

    Journal article
    Landcare Research

    A qualitative examination was made of the yeasts in three series of samples of Omarama, Tekoa, and Taupo soils from areas of uncultivated tussock grassland at Alexandra, Bealey, and Waiouru. Thirteen species were isolated, but only five of these, Cryptococcus albidus, C. diffluens, C. terreus, Candida humicola, and C. curvata, occurred in important numbers. Except that Candida curvata was not found in the Omarama soil, all five species were common to the three soils, but a different species was dominant in each soil. Candida humicola was found almost exclusively in samples from the tussock -zone. Genetic type, climate, and potential vegetation were different for each soil. It is not possible at this point to suggest which of these factors, if any, is responsible for the difference in species pattern.

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  • The ecology, life history and parasitism of Tetrahymena [Paraglaucoma] rostrata (Kahl) Corliss

    Stout, J. D. (1954)

    Journal article
    Landcare Research

    Tetrahymena [Paraglaucoma] rostrata (Kahl, 1926) Corliss, 1952 occurs commonly in litter and occasionally in soil. It has previously been recorded from moss. In nature it feeds on cytolyzed or moribund tissue, but feeds on bacteria and flagellates in the presence of peptone. It is a facultative parasite of enchytraeid worms which it infects through degenerate setal follicles. It may also infect accidentally injured worms. The ciliates are attracted by histolysis and by peptone. Resistant cysts are formed regularly in the absence of food and encystment appears to be accelerated by crowding. Excystment is readily obtained with hypotonic salt solution. Theront, trophont, tomont and tomite stages are recognizable in the life cycle. Conjugation has never been observed.

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  • Candida albicans from grass leaves

    di Menna, M. E. (1958)

    Journal article
    Landcare Research

    Reprinted from Nature, Vol. 181, pp. 1287-1288, May 3, 1958.

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  • Note on an apparatus for the rapid dispensing of agar into test-tubes

    Johnston, H. W. (1951)

    Journal article
    Landcare Research

    Reprinted from the New Zealand Journal of Science and Technology, Sec. B, Vol. 32, No. 5, March 1951, pp. 25-26.

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  • Stability of index minerals in soils with particular reference to quartz, zircon, and garnet

    Raeside, James D. (1959)

    Journal article
    Landcare Research

    In soil studies a group of index minerals has been generally accepted as sufficiently stable to be used as the basis for evaluating changes in soil profiles. Three of the minerals, quartz, garnet, and zircon, are shown to be susceptible to physical breakdown through strain caused by crystal disorientation or crystalline inclusions. Some varieties of garnet are susceptible to weathering, notably those with high iron content, and both quartz and zircon may be susceptible to solution. These minerals should, therefore, be used only in circumstances where physical or chemical changes can be excluded and where the minerals are free from crystalline inclusions and strain.

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  • Mycelial aggregation of sand soil under Pinus radiata

    Thornton, R. H.; Cowie, J. D.; McDonald, D. C. (1956)

    Journal article
    Landcare Research

    Reprinted from Nature, Vol. 177, pp. 231-232, Feb. 4, 1956.

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