bluuebunny/crossref_metadata_2025 huggingface dataset:
Lateral migration of hillcrests in response to channel incision in soil‐mantled landscapes
Authors: Mudd Simon Marius , Furbish David Jon
Published: December 2005

We investigate lateral migration of hillcrests in response to vertical offsets or transient incision rates of channels bordering these hillcrests in soil‐mantled landscapes. For hillslopes undergoing sediment transport that is linearly proportional to the slope, the hillcrest offset distance is one quarter of the ratio of the vertical offset between the channels to the relief of the symmetric hillslope. If channels are downcutting at different rates, the speed of hillcrest migration will depend on the ratio of the downcutting rates and the density ratio, which is the ratio of the bulk density of the bedrock to the bulk density of the soil. The density ratio plays a fundamental role in determining the transient response of the hillcrest; lower‐density ratios lead to faster transient responses to changes in channel downcutting rates. Other parameters that affect the transient response of the hillcrest are the magnitude of transient differences in downcutting between the two channels, the time‐averaged incision rate, and a ratio of the elevation of the hillslope to a length that characterizes the decay in soil production with increasing soil thickness; different parameters will be important for different sediment flux laws. The profile of soil thickness reacts to transient changes in downcutting at a different rate than surface topography. Hillslopes experiencing transient channel downcutting may have surface topography that is symmetric about the hillcrest but will at the same time have a soil thickness profile that is asymmetric.
Integrating Case‐control and TDT Studies
Authors: Kazeem G. R. , Farrall M.
Published: December 2005

Genetic‐association studies are widely expected to unravel the genetic basis of complex diseases. The population‐based case‐control study, a commonly used approach for association studies, is subject to the problem of population admixture. Consequently, evidence of disease‐marker associations obtained from such studies is ideally confirmed by alternative methods. The Transmission/Disequilibrium Test (TDT) is suitable to assess evidence of association obtained from case‐control studies. Since data are increasingly available from both case‐control and TDT studies of the same disease‐marker association, it is useful to obtain a combined estimate of disease‐marker association. The odds ratio is a commonly used measure of the magnitude of a disease‐marker association that can be easily obtained in case‐control studies. Here we show how an odds ratio estimate and its' associated standard error can be obtained from TDT results. Furthermore, we suggest a method for integrating results from case‐control studies and the TDT to provide a combined estimate of disease‐marker association. Such combined estimates can be used to contrast the results of the two studies and provides an overall picture of the effect size attributable to such polymorphism. An illustrative application is made to a published data set on type 2 diabetes.
Application of the Stepwise Focusing Method to Optimize the Cost‐effectiveness of Genome‐wide Association Studies with Limited Research Budgets for Genotyping and Phenotyping
Authors: Ohashi Jun , Clark Andrew G
Published: December 2005

The recent cataloguing of a large number of SNPs enables us to perform genome‐wide association studies for detecting common genetic variants associated with disease. Such studies, however, generally have limited research budgets for genotyping and phenotyping. It is therefore necessary to optimize the study design by determining the most cost‐effective numbers of SNPs and individuals to analyze. In this report we applied the stepwise focusing method, with two‐stage design, developed by Satagopan et al. (2002) and Saito & Kamatani (2002), to optimize the cost‐effectiveness of a genome‐wide direct association study using a transmission/disequilibrium test (TDT). The stepwise focusing method consists of two steps: a large number of SNPs are examined in the first focusing step, and then all the SNPs showing a significant P‐value are tested again using a larger set of individuals in the second focusing step. In the framework of optimization, the numbers of SNPs and families and the significance levels in the first and second steps were regarded as variables to be considered. Our results showed that the stepwise focusing method achieves a distinct gain of power compared to a conventional method with the same research budget.
A Dominant form of Congenital Stationary Night Blindness (adCSNB) in a Large Chinese Family
Authors: Liu Xiaoling , Zhuang Shulin , Hu Songnian , Zhang Feng , Lin Bing , Li Xu , Xu Donbin , Chen Shi‐Han
Published: December 2005

A pedigree of congenital stationary night blindness (CSNB) is described in a large Chinese family. The clinical description, pedigree, dark adaptation and elctroretinogram (ERG) studies indicate that the patients have an autosomal dominant form (ad) of CSNB. The disorder has been transmitted through at least 12 generations with over 40 affected individuals identified. The ERG data reveal that affected persons have severely diminished b‐wave responses to dim light, but normal a‐wave and subnormal b‐wave responses to maximum light stimuli. The dark adaptation curves of three patients show a monophase curve, typical for night blindness. We have excluded the five previously known mutations in the three genes (RHO, PDE6B and GNAT1) associated with adCSNB, and linkage studies have excluded tight linkage between the disease locus and markers associated with these three genes. Thus, this family has adCSNB caused by a different gene from the previously identified RHO, PDE6B, and GNAT1.
Corporate ownership structure and performance in Europe
Authors: Kirchmaier Thomas , Grant Jeremy
Published: December 2005

In this paper, we show that ownership structures vary considerably across the largest European economies, and that ownership has a significant impact on firm performance. We demonstrate that ownership structures in Europe are not necessarily consistent with value maximisation principles. Ultimately, the results show that dominant shareholders have a negative impact on long‐term share price performance. These findings are in contradiction to similar research based on US samples. Our results remain robust after controlling for industry and country effects, size and the type of owner. We base our analysis on a new and unique data set of uniform and reliable ownership data of the largest 100 public firms in the five major European economies. We quantify the differences in ownership by comparing three distinct ownership structures of firms, and relating them to performance. In addition to standard performance measures, we employ, for the first time, a Hodrick—Prescott filter. This methodology is widely used in macroeconomics to isolate the trend growth components from cyclical fluctuations. Here it is deployed to estimate the share price trend of each firm.
The management of projects and product experimentation: examples from the music industry
Authors: Lorenzen Mark , Frederiksen Lars
Published: December 2005

The paper is conceptual, combining project and economic organization literatures in order to explain the organization and management of market‐based projects. It puts particular focus on projects set up in order to facilitate product innovation through experimentation. It investigates the internal vs market economies of scale and scope related to projects, as well as the issues of governance, planning and coordination related to reaping such economies. Incorporating transaction cost perspectives as well as considerations of labor markets, the paper explains the management of market‐organized innovation projects by virtue of localized project ecologies and local labor markets of leaders and boundary spanners. It illustrates its arguments with a case study of the recorded music industry.
Quantification of global orientational order in organic solids by magic-angle spinning deuterium NMR with rotor synchronization
Authors: Nandagopal Magesh , Utz Marcel
Published: December 2005

A new method for the characterization of orientational order in organic solids based on magic-angle spinning NMR spectroscopy is introduced. The method is related to the rotor-synchronized magic-angle spinning experiment proposed by Harbison and Spiess [Chem. Phys. Lett. 124, 128 (1986)], but exploits the anisotropy of the deuterium quadrupolar coupling instead of the carbon-13 chemical shielding anisotropy. Magic-angle spinning provides a sensitivity advantage over pseudostatic techniques; using the deuterium quadrupolar coupling makes the method applicable to systems that do not exhibit large carbon chemical shift anisotropies, such as aliphatic polymers. Due to the magnitude of the deuterium quadrupolar coupling, a large number of spinning sidebands can be reliably observed, allowing for a precise determination of the orientational distribution function. Experimental data are analyzed in terms of Wigner matrix basis functions as well as the conjugate orthogonal functions framework. Unidirectionally cold-drawn poly(ethylene) is used as an example to demonstrate the method.
Multidimensional infrared spectroscopy for molecular vibrational modes with dipolar interactions, anharmonicity, and nonlinearity of dipole moments and polarizability
Authors: Hyeon-Deuk Kim , Tanimura Yoshitaka
Published: December 2005

We present an analytical expression for the linear and nonlinear infrared spectra of interacting molecular vibrational motions. Each of the molecular modes is explicitly represented by a classical damped oscillator on an anharmonic multidimensional potential-energy surface. The two essential interactions, the dipole-dipole (DD) and the dipole-induced-dipole (DID) interactions, are taken into account, and each dipole moment and polarizability are expanded to nonlinear order with respect to the nuclear vibrational coordinate. Our analytical treatment leads to expressions for the contributions of anharmonicity, DD and DID interactions, and the nonlinearity of dipole moments and polarizability elements to the one-, two-, and three-dimensional spectra as separated terms, which allows us to discuss the relative importance of these respective contributions. We can calculate multidimensional signals for various configurations of molecules interacting through DD and DID interactions for different material parameters over the whole range of frequencies. We demonstrate that contributions from the DD and DID interactions and anharmonicity are separately detectable through the third-order three-dimensional IR spectroscopy, whereas they cannot be distinguished from each other in either the linear or the second-order IR spectroscopies. The possibility of obtaining the intra- or intermolecular structural information from multidimensional spectra is also discussed.
Quasirelativistic theory equivalent to fully relativistic theory
Authors: Kutzelnigg Werner , Liu Wenjian
Published: December 2005

The Dirac operator in a matrix representation in a kinetically balanced basis is transformed to a quasirelativistic Hamiltonian matrix, that has the same electronic eigenstates as the original Dirac matrix. This transformation involves a matrix X, for which an exact identity is derived, and which can be constructed either in a noniterative way or by various iteration schemes, without requiring an expansion parameter. The convergence behavior of five different iteration schemes is studied numerically, with very promising results.
Gold behaves as hydrogen: Prediction on the existence of a new class of boron-containing radicals, AuBX (X=F,Cl,Br)
Authors: Ghanty Tapan K.
Published: December 2005

In this Communication we have reported the prediction of a new class of compounds, AuBX (with X=F,Cl,Br), using the results obtained from ab initio quantum-chemical calculations. We have compared their electronic structures, bonding, and stability with that of the recently discovered HBX radicals and demonstrated an excellent one-to-one quantitative correspondence between the structures, nature of bonding, and stability of AuBX radicals with the corresponding HBX radicals, which is of considerable significance. Comparison has also been made with the radicals containing other coinage metal atoms, viz., CuBX and AgBX. Structurally they are found to be quite similar to the HBX radicals. However, the stability in terms of some of the bond dissociation energy values differs considerably from the corresponding values in HBX or AuBX species. This feature is attributed to the unusually high relativistic effects in gold. The present results suggest that AuBX radicals are stable enough to be prepared experimentally in analogy with the experimentally observed HBX radicals. The gold-hydrogen analogy demonstrated here quantitatively would motivate further research to predict gold analogs of novel hydride species and vice versa.
Atomic origin of hysteresis during cyclic loading of Si due to bond rearrangements at the crack surfaces
Authors: Hayes Robin L. , Carter Emily A.
Published: December 2005

The atomistic origin of fatigue failure in micron-sized silicon devices is not fully understood. Two series of density-functional theory calculations on cubic diamond Si explore the effect of surface bond formation on crack healing in systems which exhibit strong surface reconstruction. Both series introduce a separation between Si(100) layers (i.e., the crack) and allow the ions to relax to their minimum-energy configuration. The initial surface ionic positions are either bulk terminated or 2×1 reconstructed. A plot of the energy versus the introduced separation reveals that once the surfaces reconstruct, the crack is no longer able to return to the equilibrium configuration. Rather, the healed crack interface contains defects which places the flawed energy minimum at a finite strain of 3% and an increased energy of 1.13J∕m2 relative to the equilibrium configuration. The irreversible plastic deformation supports the mechanism proposed by Kahn et al. [Science 298 1215 (2002)] that invokes mechanically induced subcritical cracking to explain the delayed onset of failure.
Homogeneous nucleation of n-nonane and n-propanol mixtures: A comparison of classical nucleation theory and experiments
Authors: Gaman A. I. , Napari I. , Winkler P. M. , Vehkamäki H. , Wagner P. E. , Strey R. , Viisanen Y. , Kulmala M.
Published: December 2005

The homogeneous nucleation rates for n-nonane–n-propanol vapor mixtures have been calculated as a function of vapor-phase activities at 230K using the classical nucleation theory (CNT) with both rigorous and approximate kinetic prefactors and compared to previously reported experimental data. The predicted nucleation rates resemble qualitatively the experimental results for low n-nonane gas phase activity. On the high nonane activity side the theoretical nucleation rates are about three orders of magnitude lower than the experimental data when using the CNT with the approximate kinetics. The accurate kinetics improves the situation by reducing the difference between theory and experiments to two orders of magnitude. Besides the nucleation rate comparison and the experimental and predicted onset activities, the critical cluster composition is presented. The total number of molecules is approximated by CNT with reasonable accuracy. Overall, the classical nucleation theory with rigorous kinetic prefactor seems to perform better. The thermodynamic parameters needed to calculate the nucleation rates are revised extensively. Up-to-date estimates of liquid phase activities using universal functional activity coefficient Dortmund method are presented together with the experimental values of surface tensions obtained in the present study.
Experimental and theoretical studies of the conformational structures of the mixed clusters of 1-cyanonaphthalene with water
Authors: Fujiwara Takashige , Campos Ramos Ricardo , Zgierski Marek Z. , Lim Edward C.
Published: December 2005

A concerted experimental (mass-selective, double-resonance laser spectroscopic technique) and theoretical (correlated quantum chemistry calculation) study of hydrogen-bonded clusters of 1-cyanonaphthalene (CNN) with water has been carried out to probe geometrical structures of the conformational isomers. The structures of the two low-energy conformers of CNN–H2O and CNN–(H2O)2, calculated at the MP2/cc-pVDZ level of theory, are consistent with the mass-selective infrared-ultraviolet double-resonance spectra and the partially resolved rotational band contours of the S1←S0 origin bands. The facile loss of a neutral water molecule from the cluster ion of CNN–(H2O)2, relative to that of CNN–H2O, is in accord with the proposed structures of the clusters.
Metal-ferroelectric-metal structures with Schottky contacts. II. Analysis of the experimental current-voltage and capacitance-voltage characteristics of Pb(Zr,Ti)O3 thin films
Authors: Pintilie L. , Boerasu I. , Gomes M. J. M. , Zhao T. , Ramesh R. , Alexe M.
Published: December 2005

A modified model of metal-semiconductor contacts is applied to analyze the capacitance-voltage and current-voltage characteristics of metal-ferroelectric-metal structures. The ferroelectric polarization is considered as a sheet of surface charge situated at a fixed distance from the interface. The presumable high concentration of structural defects acting as active electric traps is taken into account by introducing a deep acceptorlike level. The model is applied on a set of metal-Pb(Zr,Ti)O3-metal samples with different Zr∕Ti ratios, deposited by different methods, and having different thicknesses, electrode materials, and electrode areas. Values around 1018cm−3 were estimated for the hole concentration from capacitance-voltage measurements. The space-charge density near the electrode, estimated from current-voltage measurements, is in the 1020–1021cm−3 range. The total thickness of the interface layer ranges from 3to35nm, depending on the Zr∕Ti ratio, on the shape of the hysteresis loop, and on the electrode material. The simulated I-V characteristics is fitted to the experimental one using the potential barrier and Richardson’s constant as parameters. The potential barrier is determined to be in the 1.09–1.37eV range and Richardson’s constant is 520Acm−2K−2.
Effect of van der Waals forces on molecularly thin lubricant in the magnetic storage head-disk interface
Authors: Dagastine Ray R. , White Lee R. , Jones Paul M. , Hsia Yiao-Tee
Published: December 2005

The disjoining pressure of lubricant in the magnetic storage device head-disk interface (HDI) was obtained using Lifshitz theory [Sov. Phys. JETP 2, 73 (1956)] and multilayer film stack model. For this purpose the normal-air-gap-centered calculation of the disjoining pressure was replaced by the lubricant-layer-centered system. In the air-centered system the attractive force between the head and media was found to increase as the lubricant layer was thinned. By switching to the lubricant-centered system the disjoining pressure in a thin film of lubricant in the HDI was found to be negative at small head-to-media separation. By equating the free lubricant disjoining pressure with the lubricant in the head-disk interface, a thinning of the lubricant in the interface due to the presence of the head was calculated. A detailed thermodynamic analysis of the disjoining pressure of the lubricant in the interface revealed that the calculated negative disjoining pressure was due to the dominance of the air-gap-centered interaction energy for small air gaps. The impact on the lubricant film in the operating hard disk drive is discussed, and the possible role of negative disjoining pressure on the lubricant accumulation rate on the slider is highlighted.
Correlating elasticity and cleavage
Authors: Lazar P. , Podloucky R. , Wolf W.
Published: December 2005

For brittle cleavage under Load Mode I, a model for single crystals is presented which derives the critical stress in terms of the cleavage energy and the uniaxial elastic modulus. The model parameters are determined by fitting to results of ab initio density functional calculations. The crucial concept for establishing an accurate correlation between cleavage and elastic properties is based on a generalization of the traditionally applied Orowan–Gilman model by introducing a localization length Lb as a new materials parameter. By that, a precise correlation between elastic and cleavage properties is established. We propose that, with an average value of Lb≈2.4Å, the critical stress can be directly estimated from the cleavage energy and the uniaxial stress within an error of ±10%.
Effective Schottky barrier lowering in silicon-on-insulator Schottky-barrier metal-oxide-semiconductor field-effect transistors using dopant segregation
Authors: Knoch J. , Zhang M. , Zhao Q. T. , Lenk St. , Mantl S. , Appenzeller J.
Published: December 2005

We present an investigation of the use of dopant segregation in Schottky-barrier metal-oxide-semiconductor field-effect transistors on silicon-on-insulator. Experimental results on devices with fully nickel silicided source and drain contacts show that arsenic segregation during silicidation leads to strongly improved device characteristics due to a strong conduction/valence band bending at the contact interface induced by a very thin, highly doped silicon layer formed during the silicidation. With simulations, we study the effect of varying silicon-on-insulator and gate oxide thicknesses on the performance of Schottky-barrier devices with dopant segregation. It is shown that due to the improved electrostatic gate control, a combination of both ultrathin silicon bodies and gate oxides with dopant segregation yields even further improved device characteristics greatly relaxing the need for low Schottky barrier materials in order to realize high-performance Schottky-barrier transistors.
Photoemission studies of passivation of germanium nanowires
Authors: Adhikari Hemant , McIntyre Paul C. , Sun Shiyu , Pianetta Piero , Chidsey Christopher E. D.
Published: December 2005

The surface of single crystal germanium nanowires grown by cold-wall chemical vapor deposition was studied by synchrotron radiation photoemission spectroscopy and also by conventional x-ray photoelectron spectroscopy. The surfaces of the nanowires are not oxidized from which we infer that they are hydrogen passivated as-grown. Exposure to laboratory atmosphere leads to germanium oxide growth with oxidation states of Ge1+, Ge2+, Ge3+, while exposure to UV light leads to a predominance of the Ge4+ oxidation state. Most of the surface oxide could be removed readily by aqueous HF treatment which presumably leaves the nanowire surface hydrogen terminated. The HF-treated surface has more limited stability in air. Alternatively, chlorine termination could be achieved by aqueous HCl treatment of the oxide-coated nanowires. This chlorine termination was found to be more stable in air than the putative hydrogen termination achieved by aqueous HF treatment.
The anatomy of the timbers of the south-west Pacific area. II. Apocynaceae and Annonaceae
Authors: Ingle HD , Dadswell HE
Published: December 2005

The results reported cover 12 genera of the family Apocynaceae and 12
genera of the Annonaceae. The anatomical features of these genera have been
summarized for each family and the results compared with published information
on the representatives of the families from other parts of the world. An
artificial key has been developed for the separation of groups of genera in the
Apocynaceae. This separation, however, does not conform with groupings
based on botanical features. Possible affinities of this family have been discussed.
In the Annonaceae separation of the genera on anatomical features has
been found to be diffcult on account of the homogeneity in wood structure of
the family as a whoIe.
The biology of Hypericum perforatum L. var. angustifolium DC (St. John's Wort) in the Ovens Valley, Victoria, with particular reference to entomological control
Authors: Clark N
Published: December 2005

A study of the biology of Hypericum perforatum L. var. angustifolium DC in the Ovens Valley, Victoria, has shown that the weed possesses characteristics that make it a difficult species for effective entomological control. They include the ability to prosper under a diversity of environmental conditions after successful establishment from seed; a great capacity for vegetative reproduction by suckering; and the delayed germination of a proportion of the seed for at least 6 years, probably owing to the presence of an inhibitor in the sticky exudate of the seed capsule. The problem of control is made more difficult by the unfavourableness of a large part of the area for the growth of other herbaceous plants capable of competing effectively with either mature Hypericum or its seedlings.The leaf-eating beetles Chysomela gemellata Rossi and C. hyperici Forst. differ greatly in their ability to destroy well-established stands of the weed. The susceptibility of mature Hypericum to defoliation depends on environmental conditions, e.g. the physical condition of the soil, which determine the
life span of the individual crown and the rate and amount of vegetative reproduction. C. hyperici is highly destructive only in stands characterized by large crowns and limited vegetative reproduction; whereas C. gemellata can eliminate any type of stand occurring in treeless areas. The difference between the insects is due to the fact that C. gemellata can sustain the process of defoliation much longer than C. hyperici. It so happens that environmental conditions most favourable for the initial multiplication of both insects occur in the very sites in which the weed is most readily controlled, i.e, where the established plants are of the type most susceptible to insect attack, and where seedling regeneration is most likely to be suppressed by the associated flora. The stands of Hypericum that occur in areas less favourable for the initial colonization by the insects are genaally more resistant to defoliation. Some of these stands, e.g. those present in eucalypt forest, cannot be destroyed by hand
defoliation sustained for longer periods than the insects can maintain the process. Frequently, plants capable of ousting mature wort damaged by insect attacks or of suppressing seedling regeneration are scarce or absent, e.g. many areas of gold dredgings. Consequently, if the insects do succeed in destroying the original stands in such sites, the weed has a good chance of successful regeneration from seed. In many such areas in which the weed was destroyed in 1946 or 1948 St. John's wort is already re-established as the predominant plant. It has either achieved its former density or is well on the way towards doing so.
The genus Triodia R. Br. (Gramineae)
Authors: Burbidge NT
Published: December 2005

The material of Triodia R.Br. available in Australia was used as a basis for a revisory study of the genus. Relationships between the species and the affinities of the genus with Plectrachne Henr. and Danthonia DC. are discussed. The opinion is expressed that the genus is better placed in the tribe Danthonieae than in the Eragrosteae. Consideration is given to the possible history of the genus in the light of recent papers on past climatic conditions in Australia.

A key is provided for the identification of 28 species and a number of varieties.

All species and varieties are fully described and most of them illustrated. The following new species are described for the first time: Triodia margineta, T. plectrachnuides, T. burkensis, T. inutilis, T. molesta, T, scariosa, T. roscida;
and T. spicata. The following varieties are also new: T. pungens var. linearis,
T. mitchelli var. breuibba, T. mitchelli var. pubivagina, T. irritans var. compacta, T. irritans var. laxispicata. In most cases, though not all, the varietal epithet
has been used where the specimens do not seem to represent truly discontinuous populations so that specific ranking was not warranted.

Maps showing the distribution of the species and varieties have been included.
The anatomy of bark. I. The genus Eucalyptus
Authors: Chattaway MM
Published: December 2005

The most characteristic microscopic features of the bark of over 150 species of Eucalyptus are described.The structure of the phloem and cortex of the eucalypt twig, the changes that occur with increasing diameter, and the differences between the deciduous and persistent barks are described and illustrated.The detailed structure of the fully developed bark and the development of features characteristic of some of the most distinctive bark types have been studied, especially in the following groups: Corymbosae and Corymbosaepeltatae, Trarwersae, Exsertae and Sub-exsertae, Globuhes, Viminules, Pachyphloiae, Frasinales, Longitudinales, Piperitales, Psathyroxyla, Buxeales, Siderophtoiae.
Difference in microspore composition of some samples from a bore at Comaum, South Australia
Authors: Cookson IC
Published: December 2005

The microspore content of samples from a bore at Comaum, S.A., has been
determined. Evidence is brought forward which suggests that the passage
from Tertiary to Mesozoic strata occurred between 620-ft and 650-ft levels.
Several new sporomorphs have been described; their affinities with living and
fossil types have been considered.
A contribution to the tertiary occurrence of the genus Dacrydium in the Australian region
Authors: Cookson IC , Pike KM
Published: December 2005

Foliage shoots and seeds of a new Tertiary species, Dacydium rhomboideum,
are described; the affinity of D. rhomboideum is discussed.A new sporomorph, Dacrydiumites florinii, is proposed for fossil pollen grains, similar to those of certain species of Dacrydium, isolated from Tertiary deposits in Australia, Tasmania, and New Guinea. Descriptions of the pollen grains of the living species Dacrydium araucurioides and Dacrydium balansae are included.
The vegetation of the south-eastern Riverina, New South Wales. I. The climax communities
Authors: Moore CWE
Published: December 2005

The results of an ecological survey of the south-eastern Riverina are presented. The general features of the environment (climate, geology, physio- graphy, and soils) are described. Twenty-three plant associations are recognized and described and these are grouped into seven alliances and two formations. The distribution of the alliances is shown on the vegetation map of the region. The relationships between the vegetation and environmental factors are discussed. There is little correlation between the vegetation and geological formations. The distribution of the communities does not appear to be closely related to climatic factors, chiefly owing to the over-riding effects of soil and topography. Evidence is presented to show that the grasslands in the Narrandera, Urana, Jerilderie area are disclimax corninunities developed from the Acacia pendub-Atriplex nummularia Alliance. The life-form spectra of each alliance and of the whole region are given and briefly discussed. There is a preponderance of henlicryptophytes and therophytes except in the Eucalyptus dealbata-E. sideroxylon Alliance which is strongly nanophanerophytic. The appendix gives a species list for each alliance, together with notes on the occurrence of species rarely found in the region.
Radial fissures in the early wood of conifers
Authors: Amos GL
Published: December 2005

In certain conifers anatomical evidence suggests that young trees may become exposed to conditions conducive to collapse during late wood formation, causing partial collapse and radial cleavages in the early wood. Living ray cells are exposed to the cavity after cleavage. Different species show different responses conditioned by the anatomy and physiology of the ray parenchyma. The cavities fill with cellular tissue in radiata pine (Pinus radiata D. Don),
with resin in Douglas fir (Pseudotsuga tarcifolia (Poir.) Britt.), and remain empty in white spruce (Picea glauoa (Moench) Voss). Evidence is presented to show that when a living protoplast is given free access to moist air, a powerful growth stimulus is applied to the cell. In radiata pine, ray parenchyma cells have primary walls only, and the response is a proliferation of these cells. In Douglas fir and white spruce, the ray parenchyma has secondary thickening and small ray tracheid pitting, precluding growth. The response is an increased metabolic rate, producing resin in Douglas fir (heartwood-forming species) and without solid end-products in white spruce (species with little contrast between sapwood and heartwood).
The effect of wind sway on the form and development of Pinus radiata D. Don
Authors: Jacobs MR
Published: December 2005

The average growth of four series of trees of Pinus radiata D. Don, which were prevented from swaying in the wind by the attachment of guy-wires, is compared with the average growth of similar series of free-swaying trees. Free-swaying trees grew more in diameter over the lower part of the trunk than stayed trees. After 10 yr the increased growth due to sway could be detected to a height on the trunk of between 25 and 30 ft. The effect of sway at a height of 4 f t was greater in a very heavily thinned test area than in a well-stocked test area. Sway caused increased diameter growth of roots near the trunk and increased eccentric trunk development along the line of the main winds. The height growth of the stayed trees was little different from that of the free-swaying trees, but height/diameter relationships were changed. After 2 yr trees that had been prevented from swaying were no longer stable in a normal environment. When the upper parts of stayed trees were allowed to sway the trees made good use of the factors of the locality for 8 yr. In a series where stayed trees
were prevented from swaying throughout their length progressive suppression of diameter and volume increment was observed over 15 yr. Individual reaction to the stimulus of sway appeared to be one of the factors that contributed to the progressive assertion of dominance by certain trees.
The fossil occurrence of Phyllocladus and two other Podocarpaceous types in Australia
Authors: Cookson IC , Pike KM
Published: December 2005

Anatomical features which confirm the early Tertiary occurrence of Phyllocladus in Australia have been described. Phyllocladus morwellensis Deane has been more clearly defined; the sporomorph Phyllocladus palaeogenicus has been described and its distribution recorded. A new sporomorph, Trisaccites micropterus, has been established for certain 3-winged fossil pollen grains isolated from Mesozoic and Tertiary deposits. The distribution of the sporomorph Micocachryidites antarcticus Cookson in Australian deposits has been traced.
The wood anatomy of New Guinea Nothofagus B1
Authors: Dadswell HE , Ingle HD
Published: December 2005

An examination has been made of the secondary wood of available species of the genus Nothofagus B1. From the results it appears that on the basis of wood anatomy a ready separation can be made into two distinct groups within the genus: one comprising the New Guinea species (eight examined) and the other the temperate species from South America, New Zealand, and eastern Australia (14 examined). The New Guinea species can be separated easily from the remainder by the larger, less numerous vessels, the distinct bands of parenchyma, and the absence of tracheids. The results support the segregation of the New Guinea species into a separate subsection of the genus as proposed by van Steenis (1953).
Chromosome numbers in the Boronieae (Rutaceae) and their bearing on the evolutionary development of the tribe in the Australian flora
Authors: Smith-White S
Published: December 2005

Chromosome numbers are reported for 69 species, belonging to 11 genera of the Boronieae. In comparison with the other divisions of the Rutaceae, chromosome numbers are remarkably variable, and base numbers range from 7 to 19. Seven genera and 10 species belonging to other tribes and subfamilies of the Rutaceae are also reported. In common with the Aurantoideae, Xanthoxyleae, and Ruteae, the primitive number in the Boronieae is almost certainly 9. Chromosomal evolution has involved both aneuploidy and polyploidy. In both diploid and polyploid species, chromosome pairing is essentially regular. All the polyploids, even within recognized taxonomic species, are essentially of allopolyploid constitution. Two stages in the occurrence of polyploidy can be recognized — the first giving rise to groups of generic status, and the second to polyploid species within genera. Many genera possess chromosome numbers which could be derived by aneuploid reduction, followed by polyploidy. Some fundamental change in chromosonle structure in the primitive Boronieae stock is suggested as a cause of its early chromosomal instability. From a correlation of geographical and cytological data and inference, a hypothesis of the historical development of the Boronieae in Australia is presented. Following their isolation in the continent, and the occurrence of a fundamental reorganization in chromosome structure, a period of generic radiation, with changes in basic number, occurred before the Miocene. Particular chromosome numbers are characteristic of genera. Differences in base number rank as generic rather than as specific criteria. On this basis the accepted taxonomy is essentially sound, and only minor alterations are suggested. Crowea is established, and Eriostemon lanceolatzis is separated from its congeners. Some sections of Boronia are deserving of generic rank, and B. serrulata is wrongly placed in the section Terminales.
The use of point quadrats for the analysis of heathland
Authors: Winkworth RE
Published: December 2005

A brief theoretical examination of the relationships between the orientation of
leaves on a plant and the area of their projections is made and it is then shown how,
for heathland species, inclined point quadrats give appreciably different and usually
higher estimates of percentage cover than do vertical point quadrats. The use of
inclined point quadrats for estimation of percentage contribution to the vegetation is
examined and found to have no real advantage since no increase in precision is obtained
with their use. Errors caused by the thickness of point quadrat pins are found to be
large for the estimation of percentage cover in the microphyllous heathland vegetation.
These can be minimized by the use of a cross-wire sighting tube, but an experiment shows
that caution must be exercised in using this device because of the intertangling of the
foliage of the various species. Estimates of percentage contribution were hardly affected
by pin size. When pins were randomised independently over the test area, considerably lower variance for both percentage cover and contribution estimates were obtained compared
with pins held in frames of 10.
Sterile base florets in Triticum
Authors: Barnard C
Published: December 2005

The morphology of the florets in three base-sterile speltoid mutants of Triticum aestivum L. is described. In two of the three mutants the basal floret only is affected. In one of these (St1) There is a high degree of sterility in the basal floret of all spikkelets except those on the distal part of the inflorescence; in the other (St1A) the basal floret of the basal and the distal spikelets is nearly always fertile, the highest degree of sterility being developed in the spikelets towards the middle of the ear. In the third mutant (St2) two florets are usually concerned. The basal floret of all spikelets except the apical one is practically always sterile. The second floret in the distal spikelets is mostly fertile, but in the lower spikelets it too is sterile and there is a gradient in fertility form distal to basal spikelets. The minimal effect of the sterility factor is the abortion or complete suppression of the anterior Stamen. This is accompanied by fusion and increased growth of the lodicule rudiments; all other floral parts develop normally. Greater incidence of the sterility results in the suppression of the lateral stamens with increased development of the lodioular structure and reduced growth of the palea. Fusion of the reduced
palea and lodicular structure is usually followed by the abortion of the gynaeceum. In its extreme expression the sterility factor suppresses entirely the initiation of the flower primordium. Failure of florets in higher positions on the spikelets to form grain is due to immaturity and is different from basal sterility. When the basal florets are sterile, florets in higher positions than usual set grain. The mechanism by which the St genes operate and the evolutionary significance of basal sterility is discussed.
The anatomy of the timbers of the south-west Pacific area. IV. Cunoniaceae, Davidsoniaceae, and Eucryphiaceae
Authors: Ingle HD , Dadswell HE
Published: December 2005

The results reported cover 20 genera of the Cunoniaceae and the two monotypic families Davidsoniaceae and Eucryphiaceae, each closely related to the Cunoniaceae. The anatomical features of the genera of these families have been summarized. In the Cunoniaceae these results have been compared with published information on the family and with features revealed by examination of the available species from other parts of the world. A grouping of the genera of the Cunoniaceae based on their wood anatomy is given for diagnostic purposes and for comparison with botanical grouping. Anatomical relationships between the three families are discussed and points of similarity or difference between them and other families likely to be confused with them, are pointed out.
The anatomy of the timbers of the south-west Pacific area. V. Flacourtiaceae
Authors: James CF , Ingle HD
Published: December 2005

Examination of 13 genera from this area has indicated two structural groups within the timbers of the Flacourtiaceae. The wood anatomy of genera examined from areas other than the south-west Pacific area has been found to agree with these two groups. The anatomical features of each genus have been summarized and salient features set out in tabular form. From these an artificial key separating the genera, where possible, has been prepared. The grouping of the genera described based on wood anatomy is compared with the grouping of the family based on botanical features as suggested by Gilg (1925).
Anatomical features separating the Flacourtiaceae from the groups of timbers with some similar characteristics have been indicated.
Floral histogenesis in the monocotyledons. I. The Gramineae
Authors: Barnard C
Published: December 2005

The pattern of floral histogenesis in a representative species from each of six tribes of the Gramineae is shown to be similar to that described in a previous communication for Triticum. Periclinal division of sub-hypodermal cells characterizes the origin of spikelet, flower, and stamen primordia. Periclinal divisions also occur in hypodermal cells during flower and stamen formation; and such divisions are more frequent at stamen initiation than at the initiation of flower primordia. Periclinal division of dermatogen cells never occurs during the formation of these organs, but is, on the other hand, a constant feature in the formation of glumes, lemma, palea, lodicules, and carpel. The hypodermis always contributes to the tissues of the glume and lemma primordia; it less frequently contributes to the tissues of the lodicule and palea, and only occasionally to that of the carpel. The morphology of the gramineous flower is discussed on the basis of floral histogenesis and the pattern of prorascular tissues in the gynaeceum. The literature dealing with floral histogenesis and the pattern of prorascular tissues in the gynaeceum.
Floral histogenesis in the Monocotyledons. II. The Cyperaceae
Authors: Barnard C
Published: December 2005

An account is presented of floral histogenesis in Scirpus validus Vahl, Cyperus eragrostis Lam., and Carex appressa R. Br. The cells of the apex of the spikelet in the three species are arranged in a two-layered tunica over a central corpus. Histogenetically the outer and inner tunica layers behave differently and are termed dermatogen and hypodermis respectively. The same three tissue zones are recognized in the flower primordia. Periclinal division of dermatogen and hypodermal cells gives rise to
(i) the glumes or floral bracts and carpels in all species,
(ii) the perianth members in Scirpus, and
(iii) the perigynium in Carex.
These are all classified as foliar organs. Periclinal divisions in cells of the outer corpus layers, and inclined and periclinal divisions in the hypodermis, characterize the formation of flower and stamen primordia. Periclinal division of dermatogen cells never occurs. These organs
are regarded as cauline. The ovule develops directly from the growing point of the flower primordium and its integuments arise in the foliar fashion. The general pattern of histogenesis is compared with that in the Gramineae. Variations within this pattern and the interpretation of the floral structures are discussed.
Dark Island heath (Ninety-mile Plain, South Australia). IV. Soil moisture patterns produced by rainfall interception and stem-flow
Authors: Specht RL
Published: December 2005

Rainfall interception and stem-flow in the heath vegetation on the Makin sand of the Ninety-Mile Plain of South Australia are discussed. The nanophyllous shrubs, Banksia ornata and Xanthorrhoea australis, intercept and redistribute a large percentage of the rainfall. Striking differences in soil moisture contents are produced over very small distances; these differences are not conspicuous underneath the leptophyllous undershrubs, although rainfall interception by their foliage and litter may reduce the quantity of water reaching the soil.
The effect of quadrat size, plant size, and plant distribution on frequency estimates in plant ecology
Authors: Aberdeen JEC
Published: December 2005

The theoretical foundation for frequency estimates, as used in plant ecology, is discussed. An equation is derived in which the absence value is linked with the quadrat size, the plant unit size, the plant density, and the aggregation of the plant units. Graphical methods are used to estimate the density and the average size of the individuals of a species for a random distribution. Departure from a random distribution can also be detected by these methods. It is shown that if an estimate of the average plant unit size is combined with the frequency estimates, then the reliability of the results is increased considerably. The value of frequency estimates made with one, two, or more sizes of quadrats is discussed.
Some laboratory germination responses of the seeds of river red gum, Eucalyptus camaldulensis Dehn. Syn. Eucalyptus rostrata Schlecht
Authors: Grose RJ , Zimmer WJ
Published: December 2005

A method for sampling from bulked eucalypt seed for germination tests, and a special technique for testing germination of these seeds in Petri dishes are described. The seeds of Eucalyptus camaldulensis Dehn. will germinate both at constant and at alternating temperatures. They germinate best at a constant temperature of about 95°F. The seeds require light for satisfactory germination. The light requirements of all seed-lots tested were satisfied by 8 hours of light daily at a constant temperature of 95°F. Light requirements are least at temperatures close to 95°F. There is an interaction between light and temperature and the requirement for light is reduced as the temperature is increased. Stratification also reduces the requirement for light in germination. Thirty-one different lots of seeds have been studied. It has been shown that no relationship exists between environmental conditions of the locality of collection and optimum conditions for germination.