Showing papers by "James Cook University published in 1972"

The Requirement for Sodium as a Micronutrient by Species Having the C4 Dicarboxylic Photosynthetic Pathway

Abstract: Six species having characteristics of plants with the C(4) dicarboxylic photosynthetic pathway, Echinochloa utilis L Ohwi et Yabuno (Japanese millet), Cynodon dactylon L (Bermuda grass), Kyllinga brevifolia Rottb, Amaranthus tricolor L cv Early splendour, Kochia childsii Hort, and Portulaca grandiflora Hook (rose moss), responded decisively to 01 milliequivalent per liter NaCl supplied to their culture solutions initially containing less than 008 microequivalent per liter Na Chlorosis and necrosis occurred in leaves of plants not receiving sodium Portulaca failed to set flower in the sodium-deficient cultures Under similar conditions Poa pratensis L (Kentucky blue grass) having characteristics of the C(3) photosynthetic pathway made normal growth and did not respond to the addition of sodium It is concluded from these results and previously reported work that sodium is generally essential for species having the C(4) pathway but not for species with the C(3) pathway

Determination of pectic substances in plant material.

Abstract: Pectic substances have been extracted from plant material (a pasture legume, Stylosanthes humilis) by homogenisation with a solution of ammonium oxalate and oxalic acid and subsequently hydrolysed with polygalacturonase The galacturonic acid produced was determined by a modified carbazole reaction The enzymic hydrolysis step may be omitted by relying on the acid in the carbazole reaction partially to hydrolyse the pectic substances, but in doing so the sensitivity of the method is reduced sevenfold Attempts to carry out the hydrolysis with sulphuric acid before the carbazole reaction gave incomplete hydrolysis and probably decarboxylation Attempts to extract the pectic substances with alkali gave low values, probably because of incomplete extraction

Digestion of the dry matter, nitrogen, phosphorus, sulphur, calcium and detergent-fibre fractions of the seed and pod of Stylosanthes humilis contained in terylene bags in the bovine rumen.

Abstract: The rates of digestion of the separated seed and pods of Stylosanthes humilis in Terylene bags in the rumen of cattle were studied. The rates of disappearance of dry matter, N, P, S, Ca and detergent fibre fractions and lignin were examined. The magnitude of the errors of determination were assessed statistically for dry matter digestion. Four bag replications were necessary to detect differences of 20% between samples. The cell contents constituted 80% of the seed dry matter, but only 20% of the pod dry matter. Lignin content of seed was negligible (0.5%), but was high in pods (18%). The seed was rapidly digested (77% of dry matter after 48 h). This was largely due to almost complete digestion of the cell contents. The pod was only slightly digested (14% at 48 h). Protein and phosphorus appeared to be selectively solubilised, but calcium was only slowly solubilised in both seed and pod. The cell-wall constituents present were compared to the concentrations of hemicellulose and cellulose found in seed and pod by more definitive chemical methods.

Controlled failure of hollow rock cylinders in uniaxial compression

Abstract: Controlled Failure of Hollow Rock Cylinders in Uniaxial Compression Detailed consideration is given to the behavior of hollow rock cylinders loaded in uniaxial compression Elastic stress distributions calculated by the finite element method show that radial stresses are considerably lower in hollow than in solid cylinders, and that the uniformity of the stresses can be improved considerably by using loading platens having the same cross-section as the specimen Servo-controlled uniaxial compression tests carried out on solid and thick-walled cylinders of white Tennessee marble show no essential differences in the behavior of the two specimen types with similar strengths and fracture phenomena being observed In tests carried out in servo-controlled, stiff, and conventional machines, the progressive formation of large numbers of short subaxial cracks is followed by the development of macrofractures such as slabbing and shearing well past the peak of the stress-strain curve

A Numerical Study of the Nonlinear Laminar Regime of Flow in An Idealised Porous Medium

Abstract: Publisher Summary This chapter outlines a technique for obtaining solutions by solving the Navier-Stokes laminar flow equations for flow through a number of simplified and idealized porous materials The solutions presented extend the treatment in the nonlinear (non-creeping) flow range by retaining the inertia terms in the Navier-Stokes equations It has shown that retention of these inertia terms is required if a study of the non-creeping range of flow is contemplated and experimental evidence exists to illustrate that these effects become important before the onset of turbulence A few other solutions are available in this nonlinear laminar regime; however, the solutions presented are believed to be the first attempt at solving the full nonlinear laminar flow equations for a variety of idealized porous materials, and relating the results to the conventional empirical approaches Flows in the nonlinear regime are associated with non-zero Reynolds numbers, and high velocities or pressure gradients Thus, in the design of coarse filters, self-spillway rockfill dams, pumpwells, and so on, the nonlinear flow regime must be considered Further, the method of analysis can be used to illustrate the magnitude of the nonlinear effects, which are generally neglected, at very low Reynolds numbers

Studying Time-Dependent Effects in Failed Rock

Abstract: In experimental studies of failed rock, displacement must be regarded as the independent variable--violent failure occurs at the compressive strength if displacement is not controlled. Therefore, research into the time-dependent behavior of failed rock must begin with load relaxation (load decrease at constant displacement) where the independent variable is held constant. In the failure region, creep (displacement increase at constant load) rapidly causes failure; and it is impractical to attempt to apply a true constant stress condition. This method of approach is discussed and test results are presented to show the effects of a displacement hold and different displacement rates on the complete force-displacement curve for rock in uniaxial compression. In practice, a volume of rock is neither subjected to a constant force nor to a constant displacement but to a condition dictated by the unloading characteristic of the surrounding rock. A method is suggested for determining the time-dependent behavior of rock along a force-displacement line of arbitrary slope.

Tunnel diode full binary adder circuit

Abstract: A simple full binary adder circuit employing a tunnel diode and a transistor is proposed. It has a well defined operation and is capable of operating at rates up to 200 MHz.

Word associations of aboriginal adolescents: A comparison with Australian and American norms

Abstract: A recent application of word association data has been in studies of differences in language habits between culturally advantaged and culturally disadvantaged groups of children. Aultman (1970) provides some evidence of differences in the content of associative responses from children of comparable chronological age but diverse socio-economic backgrounds. Entwhistle (1970) found that word associations of first-grade children indicate that black and white slum children were more advanced linguistically than are suburban children in the U.S., but that the superiority had disappeared by the third grade and was followed by a cumulative decline. The early superiority was judged on the similarity of the type of response to that commonly made by adults. Entwhistle suggests that a factor in this early acceleration may be the slum child's almost unlimited access to the TV set, as compared with the restrictions usually placed on the suburban first-grader in terms of time and content.

An Analysis of Metal Distribution and Zoning in the Herberton Tinfield, North Queensland, Australia

Abstract: Series of emanative centers parallel and adjacent to granite-sediment contact, original ridge and cuspate structures on granite important in localization, two phases, tin-tungsten and later polymetallic ores

Relationship of print size to visual distance in reading activity of young school children

Abstract: It has been generally thought that speed of reading is related to the size of the printed matter being read. However, the theory that when reading smaller print the eye would be able to “take in” more words in the perceptual span than would be the case for reading larger print is not supported by experimental evidence. O'Brien (1962) found that reading speeds of some 650 school children in 4th, 5th and 6th grades did not differ significantly when reading print which varied in size between 8, 10, and 12 point.

Introversion/extraversion and children's aversion to social isolation and corporal punishment: a note on a failure to replicate eysenck

Abstract: The effects of introversion/extraversion on children's expressed aversion to two types of punishment (physical versus detention) were studied. It was predicted from Eysenck's personality theory that introverts would profess a comparatively greater aversion to physical punishment, and extraverts a comparatively greater aversion to detention. When the predictions were tested, results failed to support Eysenck's theory.

The significance of affect in verbal learning by subnormal children-an exploratory study

Abstract: Two matched groups of subnormal Ss (IQ 40-60) were trained to associate pictures with unfamiliar printed words. The pictures used for Group A were less affective than those used for Group B (degree of affect was determined by the Ss' own preferences). Correct recognition was later tested by the presentation of the printed words without pictures. Group B was significantly more successful than Group A. It was suggested that an increase in the affective connotation of verbal stimuli facilitates correct recognition of those stimuli for Ss of the 40-60 IQ range.

Generating PBR Sequences for System Testing at 500megabits/Sec. and Higher Using IC Flip-Flops.

Abstract: Generating pseudo-random bit sequences at very high bit-rates is limited by the maximum switching speed of shift registers and modulo-2 adders. A system is proposed in which registers composed of integrated circuits, operating near their maximum bit-rate may be combined in parallel to produce sequences at much higher rates.

A simple, constant-flow, constant-temperature dialysis pump.

Abstract: A low‐cost pump is described, which is simple in construction and maintenance and suitable for use by out‐patients undergoing jejunal loop dialysis.