bluuebunny/crossref_metadata_2025 huggingface dataset:
Relativistic effects on the nuclear magnetic shieldings of rare-gas atoms and halogen in hydrogen halides within relativistic polarization propagator theory
Authors: Gomez Sergio S. , Maldonado Alejandro , Aucar Gustavo A.
Published: December 2005

In this work an analysis of the electronic origin of relativistic effects on the isotropic dia- and paramagnetic contributions to the nuclear magnetic shielding σ(X) for noble gases and heavy atoms of hydrogen halides is presented. All results were obtained within the 4-component polarization propagator formalism at different level of approach [random-phase approximation (RPA) and pure zeroth-order approximation (PZOA)], by using a local version of the DIRAC code. From the fact that calculations of diamagnetic contributions to σ within RPA and PZOA approaches for HX(X=Br,I,At) and rare-gas atoms are quite close each to other and the finding that the diamagnetic part of the principal propagator at the PZOA level can be developed as a series [S(Δ)], it was found that there is a branch of negative-energy “virtual” excitations that contribute with more than 98% of the total diamagnetic value even for the heavier elements, namely, Xe, Rn, I, and At. It contains virtual negative-energy molecular-orbital states with energies between −2mc2 and −4mc2. This fact can explain the excellent performance of the linear response elimination of small component (LR-ESC) scheme for elements up to the fifth row in the Periodic Table. An analysis of the convergency of S(Δ) and its physical implications is given. It is also shown that the total contribution to relativistic effects of the innermost orbital (1s1∕2) is by far the largest. For the paramagnetic contributions results at the RPA and PZOA approximations are similar only for rare-gas atoms. On the other hand, if the mass-correction contributions to σp are expressed in terms of atomic orbitals, a different pattern is found for 1s1∕2 orbital contributions compared with all other s-type orbitals when the whole set of rare-gas atoms is considered.
Second- and third-harmonic generation in birefringent photonic crystals and microcavities based on anisotropic porous silicon
Authors: Soboleva I. V. , Murchikova E. M. , Fedyanin A. A. , Aktsipetrov O. A.
Published: December 2005

One-dimensional anisotropic photonic crystals and microcavities based on birefringent porous silicon are fabricated. The reflectance spectra demonstrate the presence of photonic band gap and microcavity modes with spectral positions tunable upon the sample azimuthal rotation around its normal and/or rotation of polarization plane of incident light. Simultaneous enhancement of second- and third-harmonic generation at the photonic band-gap edge due to the phase matching is observed. The angular positions of the second- and third-harmonic peaks are controllable via the anisotropy of the refractive indices of porous silicon layers.
Estimating the transfer function of the cantilever in atomic force microscopy: A system identification approach
Authors: Stark Martin , Guckenberger Reinhard , Stemmer Andreas , Stark Robert W.
Published: December 2005

Dynamic atomic force microscopy (AFM) offers many opportunities for the characterization and manipulation of matter on the nanometer scale with a high temporal resolution. The analysis of time-dependent forces is basic for a deeper understanding of phenomena such as friction, plastic deformation, and surface wetting. However, the dynamic characteristics of the force sensor used for such investigations are determined by various factors such as material and geometry of the cantilever, detection alignment, and the transfer characteristics of the detector. Thus, for a quantitative investigation of surface properties by dynamic AFM an appropriate system identification procedure is required, characterizing the force sensor beyond the usual parameters spring constant, quality factor, and detection sensitivity. Measurement of the transfer function provides such a characterization that fully accounts for the dynamic properties of the force sensor. Here, we demonstrate the estimation of the transfer function in a bandwidth of 1MHz from experimental data. To this end, we analyze the signal of the vibrations induced by snap-to-contact and snap-off-contact events. For the free cantilever, we determine both a parameter-free estimate [empirical transfer function estimate (ETFE)] and a parametric estimate of the transfer function. For the surface-coupled cantilever the ETFE is obtained. These identification procedures provide an intrinsic calibration as they dispense largely with a priori knowledge about the force sensor.
Enhancement of flux pinning and critical currents in YBa2Cu3O7−δ films by nanoscale iridium pretreatment of substrate surfaces
Authors: Aytug T. , Paranthaman M. , Gapud A. A. , Kang S. , Christen H. M. , Leonard K. J. , Martin P. M. , Thompson J. R. , Christen D. K. , Meng R. , Rusakova I. , Chu C. W. , Johansen T. H.
Published: December 2005

We have acquired positive results in a controlled study to investigate the effects of substrate surface modification on the growth-induced flux-pinning nanostructures in YBa2Cu3O7−δ (YBCO) films. Nanoscale iridium (Ir) particles were applied to single-crystal SrTiO3 substrate surfaces using dc-magnetron sputtering. Superconducting properties of YBCO films grown on the Ir-modified substrates, measured by transport and magneto-optical imaging, have shown substantial improvement in the critical current densities (Jc) at 77 K over those on untreated, control substrates. Results also show a nearly uniform enhancement of Jc over all orientations of magnetic field. Present results are found to be consistent with cross-sectional transmission electron microscopy investigations. Ultimately, the objective of this approach is to produce enhancements in the properties of coated conductors by a simple pretreatment of the substrate surface.
Radio-frequency power-assisted performance improvement of a magnetohydrodynamic power generator
Authors: Murakami Tomoyuki , Okuno Yoshihiro , Yamasaki Hiroyuki
Published: December 2005

We describe a radio-frequency (rf) electromagnetic-field-assisted magnetohydrodynamic power generation experiment, where an inductively coupled rf field (13.56MHz, 5.2kW) is continuously supplied to the disk generator. The rf power assists the precise plasma ignition, by which the otherwise irregular plasma behavior was stabilized. The rf heating suppresses the ionization instability in the plasma behavior and homogenizes the nonuniformity of the plasma structures. The power-generating performance is significantly improved with the aid of the rf power under wide seeding conditions: insufficient, optimum, and excessive seed fractions. The increment of the enthalpy extraction ratio of around 2% is significantly greater than the fraction of the net rf power, that is, 0.16%, to the thermal input.
Transient drop deformation upon startup of shear in viscoelastic fluids
Authors: Yue Pengtao , Feng James J. , Liu Chun , Shen Jie
Published: December 2005

Recent experiments show that upon abrupt start of a shear flow, a suspended drop undergoes an overshoot in deformation if either the drop or the matrix is a polymeric fluid. Using a diffuse-interface formulation, we carry out two-dimensional numerical simulations that trace the origin of the transient to the mismatch of two time scales: a capillary time for drop deformation and a relaxation time for the polymers in the viscoelastic component. The results are in qualitative agreement with experiments.
Effect of particle inertia and gravity on the turbulence in a suspension
Authors: Ooms G. , Poesio P.
Published: December 2005

A theoretical model is presented for the effect of particle inertia and gravity on the turbulence in a homogeneous suspension. It is an extension of the one-fluid model developed by L’vov, Ooms, and Pomyalov [Phys. Rev. E 67, 046314 (2003)], in which the effect of gravity was not considered. In the extended model the particles are assumed to settle in the fluid under the influence of gravity due to the fact that their density is larger than the fluid density. The generation of turbulence by the settling particles is described, with special attention being paid to the turbulence intensity and spectra. A comparison is made with direct numerical simulation calculations and experimental data. Also a sensitivity study is carried out to investigate at which conditions the gravity effect becomes important.
Using exchange bias to extend the temperature range of square loop behavior in [Pt∕Co] multilayers with perpendicular anisotropy
Authors: Sort J. , Garcia F. , Auffret S. , Rodmacq B. , Dieny B. , Langlais V. , Suriñach S. , Muñoz J. S. , Baró M. D. , Nogués J.
Published: December 2005

The temperature dependence of the magnetic properties of [Pt∕Co] multilayers (ML), exhibiting perpendicular anisotropy, with and without exchange biasing with an antiferromagnet (AFM) has been investigated. Upon heating, a loss of the out-of-plane anisotropy and, consequently, of the remanence to saturation ratio is observed in these systems. However, such effect occurs at higher temperatures in the [Pt∕Co] ML exchange coupled to the AFM than for the unbiased ML. This is attributed to the additional anisotropy induced to the ML by the ferromagnetic-antiferromagnetic exchange coupling.
Tunable defect mode in a three-dimensional photonic crystal
Authors: Mertens G. , Wehrspohn R. B. , Kitzerow H.-S. , Matthias S. , Jamois C. , Gösele U.
Published: December 2005

Three-dimensionally periodic structures made of macroporous silicon with varying pore diameter show a photonic stop band in the middle infrared spectral range. A discontinuity of the periodic pore width modulation forms a planar optical resonator with a corresponding transmission peak in the stop band. Infiltration of the porous structure with a nematic liquid crystal and subsequent temperature changing cause a spectral shift of the defect mode. The experimental observations are in good agreement with theoretical calculations.
Strain-induced anisotropy in microwave dielectric properties of (Ba,Sr)TiO3 thin films with directly applied uniaxial ⟨100⟩ stress
Authors: Chang Wontae , Pond Jeffrey M. , Kirchoefer Steven W. , Bellotti Jeffrey A.
Published: December 2005

The microwave dielectric properties and their change with applied uniaxial ⟨100⟩ stress in an epitaxially deposited Ba0.6Sr0.4TiO3 thin film on (001) MgO have been measured as a function of dc bias (0 to ±40V) and frequency (1–20 GHz). A significant increase in the relative dielectric constant (from 480 to 530) is observed when uniaxial stress is applied. Similarly, the dielectric tuning of the film at an applied electric field of 4×104V∕cm increases from 43% to 48% at 10 GHz. These increases correspond to an extremely small increase of the in-plane lattice parameter of the film, a, from 3.965 to 3.967 Å, (i.e., ∼0.05%) due to the applied uniaxial tensional stress.
Characterization of off-axis MgB2 epitaxial thin films for planar junctions
Authors: Iavarone M. , Karapetrov G. , Menzel A. , Komanicky V. , You H. , Kwok W. K. , Orgiani P. , Ferrando V. , Xi X. X.
Published: December 2005

Using scanning tunneling spectroscopy, we perform a full mapping of the quasiparticle density of states of magnesium diboride (MgB2) epitaxial thin films grown on (110) yttrium stabilized zirconia (YSZ) by hybrid physical-chemical vapor deposition. The films have critical temperatures of 40 K. X-ray measurements show an epitaxial MgB2 growth having the c-axis tilted by 32° with respect to the normal to the substrate, consistent with the atomic force microscopy images of the sample. Scanning tunneling spectroscopy clearly finds that the spectroscopic peak associated to the π gap is reduced on most of the film surface and the feature representative of the σ gap is present, with different intensity, on the majority of the sample’s surface, which is consistent with x-ray measurements.
Current-driven domain-wall motion in magnetic wires with asymmetric notches
Authors: Himeno A. , Kasai S. , Ono T.
Published: December 2005

Current-driven domain-wall (DW) motion in magnetic wires with asymmetric notches was investigated by means of magnetic force microscopy. It was found that the critical current density necessary for the current-driven DW motion depended on the propagation direction of the DW. The DW moved more easily in the direction along which the slope of the asymmetric notch was less inclined.
Highly polarized polymer light-emitting diodes utilizing friction-transferred poly(9,9-dioctylfluorene) thin films
Authors: Misaki Masahiro , Ueda Yasukiyo , Nagamatsu Shuichi , Chikamatsu Masayuki , Yoshida Yuji , Tanigaki Nobutaka , Yase Kiyoshi
Published: December 2005

Polarized polymer light-emitting diodes (PLEDs) have been constructed utilizing friction-transferred poly(9,9-dioctylfluorene) (PFO) thin films. The friction transfer technique allows oriented PFO to be deposited directly onto an indium tin oxide anode without an alignment layer such as polyimide. Polarized absorption and photoluminescence spectra revealed that the polymer backbones are highly aligned in the friction direction. We fabricated PLEDs consisting of friction-transferred PFO as an emissive layer, vacuum-deposited bathocuproine as an electron transport and hole-blocking layer, and a vacuum-deposited LiF∕Al cathode. Highly polarized blue emission with an integrated polarization ratio of 31 and a luminance of up to 300cd∕m2 was observed from the PLEDs.
Anisotropic properties of ultrafast laser-driven microexplosions in lithium niobate crystal
Authors: Zhou Guangyong , Gu Min
Published: December 2005

Smooth voids are achieved in an anisotropic Fe:LiNbO3 crystal with a high refractive index by use of a femtosecond laser-driven microexplosion method. Due to the anisotropy of the crystal, the maximum fabrication depth and the fabrication power threshold are different in different crystal directions, indicating that the direction perpendicular to the crystal axis is more suitable for thick three-dimensional structure fabrication. The dependence of the threshold power on the illumination wavelength shows that the microexplosion mechanism is caused by a two-photon absorption process. As a result, a near threshold fabrication method can be used to generate quasispherical voids.
Spatially periodic liquid crystal director field appearing in a photonic crystal template
Authors: Matthias Heinrich , Röder Thorsten , Wehrspohn Ralf B. , Kitzerow Heinz-S. , Matthias Sven , Picken Stephen J.
Published: December 2005

Active tuning of photonic crystals can be achieved by filling the porous structures with liquid crystals. Here, the director field in macropores was studied by fluorescence confocal polarizing microscopy. For this purpose, the photonic crystal was infiltrated with a glass-forming liquid crystalline polymer, the sample was cooled below the glass transition temperature and, subsequently, the photonic crystal template was removed. Results on a structure with modulated pores indicate a spatially periodic director field containing a lattice of disclination rings.
Transmission electron microscopy study on ion-beam-synthesized amorphous Fe–Si thin layers
Authors: Naito Muneyuki , Ishimaru Manabu , Hirotsu Yoshihiko , Valdez James A. , Sickafus Kurt E.
Published: December 2005

Ion-beam-synthesized amorphous Fe–Si thin layers have been characterized using transmission electron microscopy (TEM) in combination with imaging plate techniques. Si single crystals with a (111) orientation were irradiated with 120keV Fe+ ions to a fluence of 4.0×1017cm−2 at cryogenic temperature (120K). Cross-sectional TEM observations indicated the formation of an amorphous bilayer on the topmost layer of the Si substrate. It was found that the upper layer is an amorphous Fe–Si with the composition, in terms of atomic ratio, of Fe∕Si ∼1∕2, while the lower one is an amorphous Si. Atomic pair-distribution functions extracted from microbeam electron diffraction patterns revealed that the nature of short-range order in amorphous Fe–Si thin layer can be well described by the atomic arrangements of crystalline iron silicides.
High-gain and low-threshold InAs quantum-dot lasers on InP
Authors: Caroff P. , Paranthoen C. , Platz C. , Dehaese O. , Folliot H. , Bertru N. , Labbé C. , Piron R. , Homeyer E. , Le Corre A. , Loualiche S.
Published: December 2005

InAs quantum-dot (QD) laser structures are grown on (113)B-oriented InP substrate by gas-source molecular-beam epitaxy. Following an optimized growth procedure, a high density of 1.1×1011cm−2 of uniformly sized QDs is achieved. Broad-area lasers containing three stacked QD layers have been realized and tested. Laser emission on the ground-state transition (λ=1.59μm) is obtained at room temperature (RT), at a threshold current density as low as 190A∕cm2. Ground-state modal gain and transparency current density is measured to be 7cm−1 and 23A∕cm2 per dot layer. Ground-state laser emission is also demonstrated from low temperature (100 K, Jth=33A∕cm2) to high temperature (350 K), exhibiting an insensitive threshold in the [100, 170] K range, and a 55 K characteristic temperature at RT.
Exploring the Role of the Business Support Infrastructure in Albania: The Need for a Rethink?
Authors: Xheneti Mirela
Published: December 2005

The role of entrepreneurship and small businesses in economic development has received particular attention in the postcommunist countries. Transition studies have recently emphasised the role that institutions play in orienting the entrepreneurial spirit toward capital formation, investment, export expansion, and generation of new jobs, and fair competition which will lead to sustainable economic growth. The author discusses the business-support infrastructure in Albania and the operational issues it faces. Interview data have been collected from various actors involved in the development of small and medium-sized enterprises in the country. The combination of the interview content with background information on each of the organisations has highlighted various issues such as the need for greater exposure of enterprises to business opportunities through the promotion of role-model businesses, the need to respond to the specific needs of enterprises in terms of skills and knowledge, and the need for a wider access through a better sectoral and regional coverage.
Effectiveness at What? The Processes and Impact of Community Involvement in Area-Based Initiatives
Authors: Goodlad Robina , Burton Paul , Croft Jacqui
Published: December 2005

Community involvement is seen both as means and as ends in contemporary urban policy, and although increasingly popular with policymakers it is not universally welcomed. Incredulous opponents assert that it does not improve the position of poor people and that it distracts attention from structural inequalities, whereas sceptical believers hold that it boosts social cohesion, and improves the position of powerless groups. The authors provide a framework for understanding these conflicting accounts of the processes and impact of community involvement in area-based initiatives (ABIs). They draw on a review of the relevant literature commissioned by the Home Office. The work is grounded in theories of democracy that claim both developmental and instrumental benefits for participants. A third rationale is found in ‘due process' claims for involvement as a fundamental right. This framework suggests that answering questions about what works in community involvement in ABIs requires an empirical focus on aims, processes, and effects. The evidence shows that believers are justified in being sceptical but optimistic, and that opponents will remain incredulous in the light of weaknesses in the practice and outcomes of community involvement in ABIs. The authors conclude by discussing the implications for policy and future research.
Public Sector Relocation and Regional Disparities in Britain
Authors: Marshall J Neill , Hodgson Catherine , Bradley David
Published: December 2005

The authors use the government-commissioned Lyons review proposals for the relocation of approximately 20 000 public sector jobs from London and the South East of England as a springboard for a historical analysis of civil service dispersal in Britain. Though civil service dispersal has helped ameliorate regional disparities, this has been a secondary objective of relocation programmes. The authors highlight the interconnections between public sector relocation and civil service (re)organisation. In the 1960s and 1970s, relocation formed part of a national programme to accommodate the geographical consequences of the hierarchical and spatially centralised public sector by relocating routine functions from the capital. Today, relocation is part of a coordinated programme of public sector reform which seeks to slim down the central headquarters of the civil service—so that only strategic aspects of policy and management are concentrated in London. In the Lyons review regional development is taken more seriously than in previous programmes of relocation; however, the links between the Lyons review and Gershon's review of public sector efficiency suggests that, in the short term at least, the primary emphasis remains on reducing costs and achieving efficiency savings.
The Synthesis of Almazoles A and B
Authors: Khalafy Jabbar , Prager Rolf H. , Williams Craig M.
Published: December 2005

Almazoles A (1) and B (2) are formed in seven steps from phenylalanine without
any racemization. The key step is the N-acylation of the
isoxazol-5(2H)-one (5) with the phthalimide-protected
amino acid, and photolysis of the product at 300 nm in acetone.
Mercury(II) and Lead(II) Complexes of 1-Oxa-7-thia-4,10-diazacyclododecane ([12]aneN2OS)
Authors: Hambley Trevor W. , Afshar Shahara , Marcus Sebastian T. , Gahan Lawrence R.
Published: December 2005

The mixed donor 12-membered macrocyclic ligand
1-oxa-7-thia-4,10-diazacyclododecane
([12]aneN2OS) has been synthesized and the
mercury(II) and lead(II) complexes,
[Hg([12]aneN2OS)(NO3)2]
and
[Pb([12]aneN2OS)(NO3)2],
have been isolated and characterized by X-ray crystallography. Crystals of the
mercury complex are monoclinic, space group P
21/c, a
9·576(2), b 10·757(2),
c 14·789(4) Å, β 93·58(2)°,
whilst crystals of the lead complex are monoclinic, space group
P 21/n,
a 19·490(7), b
8·010(2), c 19·576(6) Å, β
109·90(2)°. The protonation constants and stability constants have
been determined potentiometrically in aqueous solution. The protonation
constants for [12]aneN2OS (log
KHL 9·13; log
K H2L 6·85) appear typical
for secondary amines in similar trans-substituted
12-membered macrocycles. The magnitudes of the stability constants
(HgII, log
KHgL 10·5;
PbII, log
KPbL 6·6) are consistent
with trends observed previously for macrocyclic ligands as secondary amine
donors are replaced with oxygen and thioether donors.
Molecular Adducts of 2,6-Diaminopyridine with Nitro-Substituted Aromatic Carboxylic Acids and the Crystal Structure of the 1 : 1 Adduct of 2,6-Diaminopyridine with 2-Nitrobenzoic Acid
Authors: Smith Graham , Pascoe Catherine E. , Kennard Colin H. L. , Byriel Karl A.
Published: December 2005

The 1 : 1 adducts of 2,6-diaminopyridine (2,6-dap) with a series of
nitro-substituted aromatic carboxylic acids have been prepared and the crystal
structure of one of these, with 2-nitrobenzoic acid (2-nba),
[(2,6-dap)+ (2-nba)-]
has been determined by X-ray crystallography and refined to a residual
R 0·034 for 655 observed reflections. Crystals
are monoclinic, space group P
21/c, with four molecules in a
cell of dimensions a 7·376(2),
b 22·837(3), c
7·716(2) Å, β 90·01(2)°. The structure involves
proton transfer with the resulting pyridinium proton and an amine proton
combining with the carboxyl oxygens of the 2-nba molecule in a primary cyclic
hydrogen-bonding association. Additional interactions, involving all the
remaining amine protons of 2,6-dap with both carboxyl oxygens and one nitro
oxygen of 2-nba, complete a chain polymer structure. All other members of this
series have been confirmed by infrared spectroscopy as proton transfer
adducts.
Constituents of Conospermum brachyphyllum. Improved Methods for the Isolation and Synthesis of (+)-Conocurvone and the Structure of (+)-Brachyphyllone
Authors: Armstrong James A. , Baker Robert W. , Best Wayne M. , Byrne Lindsay T. , Cannon Jack R. , Colegate Steven M. , Gray Anthony R. , Marchant Neville G. , Rothnie Neil , Sargent Melvyn V. , Sims Colette G. , Spadek Zdzislaw E. , Trengove Robert D.
Published: December 2005

Improved methods have been devised for the isolation of (+)-conocurvone
(1) from the roots of Conospermum brachyphyllum Lindl.
and for its synthesis. The isolation of
(R)-(+)-9-hydroxy-3-(4′-hydroxy-4′-methylpentan-1′-yl)-3,8-dimethyl-3H-naphtho[2,1-b]pyran-7,10-dione
[(+)-brachyphyllone] (2), a minor constituent of this species,
its structural elucidation and partial synthesis are also described.
8-C-Methylteretifolione-B (9) and
8-C-methyl-9-O-methylteretifolione-B (10), as well as
the previously isolated (+)-teretifolione-B (8), also occur in this
plant.
A comparison of the soils from two areas of sorted step chenopod patterned ground, at Fowlers Gap Field Station, Western New South Wales.
Authors: Macdonald BCT , Melville MD
Published: December 2005

Sorted step patterned ground at Fowlers Gap Field Station occurs within a variety of different Landsystem Units. Areas of sorted step patterned ground from Nuntherungie and Gap Hills Landsystems were selected and the soil properties compared. Soils from areas of sorted step patterned ground are composed of bare saline soils which surround the less saline vegetated soils. Despite occurring within different Landsystems, the suite of soil chemical properties (EC, soluble cations, and pH) between the bare and vegetated area within the patterned ground were statistically the same in most cases. Differences in the suite of soil salts probably arise from variations in gilgai microtopography.
The potential of synthetic aperture radar (SAR) for quantifying the biomass of Australia's woodlands.
Authors: Lucas RM , Milne AK , Cronin N , Witte C , Denham R
Published: December 2005

The potential of Synthetic Aperture Radar (SAR) for estimating the above ground and component biomass of woodlands in Australia is demonstrated using two case studies. Case Study 1 (In,june; central Queensland) shows that JERS-1 SAR L HH data can be related more to the trunk than the leaf and branch biomass of woodlands. A strong relationship between L HH and above ground biomass is obtained when low biomass pasture sites are included. Case Study I1 (Talwood, southern Queensland) determines that L and P band data can be related both to trunk and branch biomass, due to the similarity in the orientation and size of these scattering elements, and also to total above ground biomass. Saturation of the C. L and P band data occurred at approximately 20-30 Mglha; 60-80 Mglha and 80-100 Mglha. These preliminary results indicate that data from SAR are useful for quantifying changes in carbon stocks resulting from land use change in Australia's woodlands and for applications in rangeland assessment and management. Key words: remote sensing, biomass, woodlands
Valuing the preservation of rangelands: Tree clearing in the desert uplands region of Queensland.
Authors: Rolfe J , Blamey R , Bennett J
Published: December 2005

Tree clearing to improve pasture production for beef cattle is becoming more commonplace in the rangeland zone in Queensland. In parts of the Desert Uplands region of Central Queensland, current clearing rates are among the highest in Australia. The state government, in granting permits for clearing, has to balance the improved production benefits, accruing mostly to pastoralists, against the biodiversity losses, which are borne more widely by Australian society. In the current debate over clearing restrictions, little information exists about the values that society may hold for the preservation of rangelands. To address this deficiency, a choice modelling study was undertaken to provide estimates of the benefits of retaining remnant vegetation that are appropriate for inclusion in a benefit cost analysis of tighter clearing restrictions. Attributes included in the choice model were reductions in the population size of non-threatened species and unique ecosystems, the number of endangered species lost to the region, and changes in regional income and employment. The benefits estimated for individual attributes, and for some more restrictive policy settings are reported. Key words: remnant native vegetation, economic valuation, grazing industry, pasture development, choice modelling
The effects of management regime and host species on Sandalwood (Santalum spicatum) recruitment near Paynes Find Western Australia.
Authors: Brand JE
Published: December 2005

Natural recruitment of sandalwood (Santalum spicatum) is generally low in pastoral regions of the Midwest and Goldfields, Western Australia. Harvesting of S, spicatum for the aromatic timber occurs in these regions, creating a need to develop management strategies to conserve the species. This paper examines sandalwood recruitment over three years within a natural stand of 32 ha, near Paynes Find, Western Australia. Santalum spzcatum recruitment success was compared between three establishment treatments, and between two fencing treatments (+I-). At age three years, mean survival of S. spicatum seedlings planted next to host trees (25%) was significantly higher than those planted at harvesting spots (2%) and beneath parent trees (0%). In the unfenced treatment, there was evidence of grazing and S, spicatum survival and growth were significantly lower than in the fenced treatment. However, fencing alone did not improve S. spicatum recruitment because natural seed dispersal was poor and survival beneath parent trees was low. De-stocking, combined with seed enriching host trees is recommended to dramatically improve S, spicatum recruitment in the Paynes Find region. Santalum spicatum seedling performance was compared growing next to three N2-fixing species (Acacia burkittii, A. tetragonophylla and A. ramulosa) and one non N2-fixing species (Hakea recurva). At age three years, S. spicatum survival was significantly higher next to A. burkittii (33%) than A. tetragonophylla (1 7%). Santalum spicatum survival next to A. ramulosa and H. recurva was 24-26%. Fencing improved S. spicatum survival next to A. burkittii, and to a lesser extent next to A. tetragonophylla and A. ramulosa. In contrast, survival of S, spicatum seedlings next to H. recurva was unaffected by fencing. Santalum spicatum growth next to each host species was slow and significantly higher in the fencing treatment. Foliar concentrations of N, P, K and Ca were the same across 5'. spicatum treatments, but the concentration of Mg varied. The foliar K:Ca ratio was also similar between S. spicatum treatments, ranging from 1.4 to 2.0. Key words: Santalum spicatum, recruitment, seed enrichment, host species, foliar nutrients
Wildlife in dry lake and associated habitats in western New South Wales.
Authors: Briggs SV , Seddon JA , Thornton SA
Published: December 2005

Intermittently and occasionally flooded lakes are common in arid and semi-arid Australia. The wetldry nature of these lakes means that they provide habitat for terrestrial fauna when dry and aquatic fauna when flooded. The fauna of dry lakes in western New South Wales is largely unknown. This study reports on species of small mammals and reptiles trapped in a dry lake in south-western New South Wales, and contrasts them with species trapped in surrounding woodland and shrubland habitats. Information on bird species in these habitats was also drawn on. Small mammals, reptiles and birds showed considerable partitioning between the habitats in the study area. The dry lake provided the main habitat for the two small mammals Smznthopsis crassicaudata and Planlgale gdesi. Reptiles were most speciose and most abundant in the blue bush (Maireana spp.) shrubland, but some reptile species were mainly or entirely confined to the dry lake habitats, or to black box (Eucalyptus largzjlorens) woodland. Birds in the study region were most abundant and most speciose in the black box woodland, with some species confined to blue bush shrubland. The study showed that conservation of all the habitats investigated is necessary to retain the suite of vertebrate species that occupy these landscapes. Key words: small mammals, reptiles, birds, arid zone, dry lake, shrubland, woodland, biodiversity: Australia
Guest editorial
Authors: Noble Jim
Published: December 2005

The last two decades of the twentieth century have seen a burgeoning interest in Australian history. Much of this interest has been engendered by major national events such as the bicentenary of European settlement in 1988 and more recently, the centenary of Federation, yet there has also been a growing public acceptance of the existence of another, less tangible, history of Australia that predates the arrival of Europeans. While reflecting a heightened sense of national confidence and maturity, this awareness also relates to a growing community concern about major environmental problems now looming on a national scale. The fact that many of these issues had emerged by the end of the nineteenth century provided clear evidence that landuse practices transplanted from elsewhere were not always sustainable in Australian environments.
It is not surprising therefore, that environmental history is seen by many today, as particularly relevant to any comprehensive analysis of land management and land management policies. Only by understanding clearly what has happened in the past through an objective examination of all available sources of information is it possible to identify critical factors and processes underpinning contemporary environmental issues.
One hundred years of environmental crisis
Authors: Griffiths Tom
Published: December 2005

Exactly a hundred years before this conference, in August 1900, a Royal Commission was appointed which 'deserves a prominent, if not defining, place in Australian environmental history' (Quinn 1995). This paper explores the social, political and environmental context of this very significant inquiry. Beginning with six edited extracts from the Commission's transcript of evidence, the paper reflects upon the enduring relevance of the inquiry today. It describes the nature of European occupation of the western lands of New South Wales in the 1860s and 70s — a period when there appeared no physical limit to pastoral expansion — and then summarises the environmental crisis of the final 20 years of the century. Nineteenth-century debates about land reform were dominated by the class struggle between squatters and selectors and by the imperative to occupy, for strategic and moral purposes, what were regarded as vacant lands. The 1901 Royal Commission gave early voice to environmental arguments for occupation, and not just cultural ones, and there was a recognition that European settlers had disrupted earlier, Aboriginal systems of habitation and management and tipped the land into an escalating instability. Legislators began to argue that the land needed people as much as people needed the land. The paper concludes with the reflection that it is not just the formality of a centenary that makes us want to listen carefully to the voices unearthed by the 1901 Royal Commission. Science is now more integrative of the social and humanist perspective than it was in the middle of the 20th century; it is more receptive to the testimony of people living on and working the land, and more eager to enter into a dialogue with them and their history.
Biodiversity conservation and vegetation clearing in Queensland: principles and thresholds
Authors: McAlpine C. A. , Fensham R. J. , Temple-Smith D. E.
Published: December 2005

Clearing of native vegetation is a major threat to biodiversity in Australia. In Queensland, clearing has resulted in extensive ecosystem transformation, especially in the more fertile parts of the landscape. In this paper, we examine Queensland, Australian and some overseas evidence of the impact of clearing and related fragmentation effects on terrestrial biota. The geographic focus is the semi-arid regions, although we recognise that coastal regions have been extensively cleared. The evidence reviewed here suggests that the reduction of remnant vegetation to 30% will result in the loss of 25–35% of vertebrate fauna, with the full impact not realised for another 50–100 years, or even longer. Less mobile, habitat specialists and rare species appear to be particularly at risk. We propose three broad principles for effective biodiversity conservation in Queensland: (i) regional native vegetation retention thresholds of 50%; (ii) regional ecosystem thresholds of 30%; and (iii) landscape design and planning principles that protect large remnants, preferably > 2000 ha, as core habitats. Under these retention thresholds, no further clearing would be permitted in the extensively cleared biogeographic regions such as Brigalow Belt and New England Tablelands. Some elements of the biota, however, will require more detailed knowledge and targeted retention and management to ensure their security. The application of resource sustainability and economic criteria outlined elsewhere in this volume should be applied to ensure that the biogeographic regions in the north and west of Queensland that are largely intact continue to provide extensive wildlife habitat.
Clearing savannas for use as rangelands in Queensland: altered landscapes and water-erosion processes
Authors: Ludwig J. , Tongway D.
Published: December 2005

This paper presents a framework and some examples of how tree clearing alters landscapes (vegetation structure and faunal habitat) and processes (run-off and soil erosion) for eucalypt savannas in Queensland. Unaltered savannas have a tree-layer and a well-covered ground-layer of perennial grasses, and they provide habitats favoured by a variety of open woodland birds, reptiles and small mammals. Because unaltered savannas have a high ground-cover, they have low rates of run-off and erosion. When savannas are chained, but otherwise unaltered, trees rapidly regrow and increase in canopy cover. The exotic buffel grass often establishes in chained regrowth (especially if grazed), although the cover of native grasses such as black speargrass remains high (unless heavily grazed). We found that open woodland birds declined on these chained regrowth sites, except for the Weebill, which increased in abundance. When savannas are cleared of trees and woody debris and developed as improved pasture systems, both exotic and native perennial grass increased in cover. However, open woodland fauna abundance declined whereas grassland fauna such as the Red-backed Fairy-wren and the House Mouse increased in abundance. If these pasture sites are heavily utilised by livestock so that ground-cover is reduced, rates of run-off and soil loss are likely to rapidly increase, especially as cover declines below 40%. These run-off and erosion findings suggest that the manner in which savanna landscapes are cleared and subsequently used will have flow-on effects at catchment scales.
Nutrient dynamics in Queensland savannas: implications for the sustainability of land clearing for pasture production
Authors: Schmidt Susanne , Lamblea Rebecca E.
Published: December 2005

Eucalyptus savannas on low nutrient soils are being extensively cleared in Queensland. In this paper we provide background information relevant to understanding nutrient (particularly nitrogen) dynamics in sub/tropical savanna, and review the available evidence relevant to understanding the potential impact of clearing Eucalyptus savanna on nutrient relations. The limited evidence presently available can be used to argue for the extreme positions that: (i) woody vegetation competes with grasses for resources, and tree/shrub clearing improves pasture production, (ii) woody vegetation benefits pasture production. At present, the lack of fundamental knowledge about Australian savanna nutrient relations makes accurate predictions about medium- and long-term effects of clearing on nutrient relations in low nutrient savannas difficult. The future of cleared savannas will differ if herbaceous species maintain all functions that woody vegetation has previously held, or if woody species have functions distinct from those of herbaceous vegetation. Research suggests that savanna soils are susceptible to nitrate leaching, and that trees improve the nutrient status of savanna soils in some situations. The nitrogen capital of cleared savanna is at risk if mobile ions are not captured efficiently by the vegetation, and nitrogen input via N2 fixation from vegetation and microbiotic crusts is reduced. In order to predict clearing effects on savanna nutrient relations, research should be directed to answering (i) how open or closed nutrient cycles are in natural and cleared savanna, (ii) which functions are performed by savanna constituents such as woody and herbaceous vegetation, native and exotic plant species, termites, and microbiotic crusts in relation to nutrient cycles. In the absence of detailed knowledge about savanna functioning, clearing carries the risk of promoting continuous nutrient depletion.
Economics of vegetation clearing in Queensland
Authors: Rolfe John
Published: December 2005

Vegetation management in Queensland has been controversial in recent years. This is because of the complexity of the issues, the different interests of the various stakeholders, and the difficulty of finding efficient and acceptable solutions. While vegetation clearing generates production benefits to landholders, it may also generate spillover effects of greenhouse gas emissions and biodiversity losses on other groups in society. As well, there are questions about impacts on sustainability where clearing is associated with risks of salinity and other land degradation impacts. This paper provides an overview of these issues from an economic perspective. Economic theory and applied results are used to explore reasons for disagreement over clearing and where the balance between private and public interests might lie. The use of regulation, property right mechanisms, taxes and community planning are discussed to address problems associated with externalities. The need for better information, changed goals and norms, and regulation are outlined in relation to sustainability issues. The justification for some different approaches to regulation is also explored.
Communicating vegetation management science to land managers and other stakeholders
Authors: Siepen G. L. , Westrup J.
Published: December 2005

Science communication, including extension services, plays a key role in achieving sustainable native vegetation management. One of the pivotal aspects of the debate on sustainable vegetation management is the scientific information underpinning policy-making. In recent years, extension services have shifted their focus from top-down technology transfer to bottom-up participation and empowerment. There has also been a broadening of communication strategies to recognise the range of stakeholders involved in native vegetation management and to encompass environmental concerns. This paper examines the differences between government approaches to extension services to deliver policy and the need for effective communication to address broader science issues that underpin native vegetation management. The importance of knowing the learning styles of the stakeholders involved in native vegetation management is discussed at a time of increasing reliance on mass communication for information exchange and the importance of personal communication to achieve on-ground sustainable management. Critical factors for effective science-management communication are identified such as: (i) undertaking scientific studies (research) with community involvement, acceptance and agreed understanding of project objectives; (ii) realistic community consultation periods; (iii) matching communication channels with stakeholder needs; (iv) combining scientific with local knowledge in an holistic (biophysical and social) approach to understanding an issue; and (v) regional partnerships. These communication factors are considered to be essential to implementing on-ground natural resource management strategies and actions, including those concerned with native vegetation management.
Size-biomass relationships for Australian populations of the invasive rangeland shrub Parkinsonia aculeata L.
Authors: Grice A. C. , Campbell S. D. , McKenzie J. R. , Whiteman L. V. , Lukitsch B. V.
Published: December 2005

Parkinsonia aculeata is an invasive, introduced shrub that is found in all mainland states of Australia except Victoria. It is especially prevalent north of the tropic of Capricorn. Size-biomass relationships were established for this species using data from 167 shrubs spread across eight sites in the Northern Territory and north-eastern Queensland. Above-ground dry weight (W, kg) can be predicted from plant height (H, m), canopy diameter (D, m) or stem cross-sectional area (A, cm2) using the equations:
W = 0.025 H4.47
W = 0.091 D3.64
W = 0.022 A1.61
These relationships are linear when plotted on log-log scales. Although there was a significant effect of "site" on the log-log relationships between above-ground dry weight and size variables, the amount of information lost by not using site-specific equations is relatively small. These results provide reliable methods for estimating above-ground biomass in this species, the most robust being based on measurements of stem diameter at 20 cm above ground level.
The influence of landforms on sandalwood (Santalum spicatum (R.Br) A.Dc.) size structure and density in the north-eastern goldfields, Western Australia
Authors: Brand J. E. , Jones P. J.
Published: December 2005

The density of Santalum spicatum was compared between 'land systems' and between 'land surface types' on four sheep stations in the north-eastern Goldfields: Yakabindie, Tarmoola, Glenorn and Minara. S.A spicatum density was recorded in 4–6A ha transect plots, with a total of 14,090 ha surveyed. Within each transect plot, the S. spicatum were divided into five groups based on stem diameter at 150A mm: < 25 mm, 25–74 mm, 75–124 mm, 125–174 mm and > 174 mm. The proportion of S. spicatum in each of the five size categories was similar between land surface types and between land systems, with the majority in two groups: 75–124 mm and 125–174 mm. S. spicatum recruitment was low, with less than 1.5 % seedlings (< 25 mm) and 7.9 % saplings (25–74 mm).
Total density of S. spicatum on hills and ridges (0.65 stems/ha) was significantly higher than any other land surface type. The sandplains (0.05 stems/ha) supported the least. Within land systems, Laverton and Bevon (both hills and ridges) had the highest S. spicatum density. Yakabindie supported higher densities of S. spicatum than the other stations.