bluuebunny/crossref_metadata_2025 huggingface dataset:
Fractional boundaries for fluid spheres
Authors: Bayin S. , Glass E. N. , Krisch J. P.
Published: January 2006

A single Israel layer can be created when two metrics adjoin with no continuous metric derivative across the boundary. The properties of the layer depend only on the two metrics it separates. By using a fractional derivative match, a family of Israel layers can be created between the same two metrics. The family is indexed by the order of the fractional derivative. The method is applied to Tolman IV and V interiors and a Schwarzschild vacuum exterior. The method creates new ranges of modeling parameters for fluid spheres. A thin shell analysis clarifies pressure/tension in the family of boundary layers.
Statistical mechanics of quantum-classical systems with holonomic constraints
Authors: Sergi Alessandro
Published: January 2006

The statistical mechanics of quantum-classical systems with holonomic constraints is formulated rigorously by unifying the classical Dirac bracket and the quantum-classical bracket in matrix form. The resulting Dirac quantum-classical theory, which conserves the holonomic constraints exactly, is then used to formulate time evolution and statistical mechanics. The correct momentum-jump approximation for constrained systems arises naturally from this formalism. Finally, in analogy with what was found in the classical case, it is shown that the rigorous linear-response function of constrained quantum-classical systems contains nontrivial additional terms which are absent in the response of unconstrained systems.
Atomic-scale rectification at microwave frequency
Authors: Tu X. W. , Lee J. H. , Ho W.
Published: January 2006

Microwave of known amplitude and frequency, irradiating the junction of a low temperature scanning tunneling microscope, was found to induce a dc signal. This rectification current is spatially localized and exhibits chemical sensitivity at the atomic scale. Dependence of the rectification current on the sample bias voltage reveals spin splitting in the electronic state of a single Mn atom and vibrations of single MnCO molecule. These results demonstrate the feasibility of atomic scale nonlinear spectroscopy and the potential for the detection of resonance phenomena excited with a spatially extended electromagnetic wave.
Probing the work function of a gate metal with a top-gate ZnO-thin-film transistor with a polymer dielectric
Authors: Lee Kimoon , Kim Jae Hoon , Im Seongil
Published: January 2006

We report on the fabrication and application of top-gate ZnO thin-film transistors (TFTs) with a poly-4-vinylphenol (PVP) gate dielectric layer formed on n-ZnO by spin casting. Al, Au, and NiOx top-gate metals patterned on the PVP of a top-gate TFT by thermal evaporation exhibited different threshold voltages (Vt) and saturation currents. This provides us with an all-electrical way to measure the work function of an unknown new electrode (NiOx) based on those of two reference electrodes (Al and Au). Our data show that the work function of semitransparent conductive NiOx is ∼5.1eV, which is larger than the value (4.95 eV) determined from capacitance-voltage (C-V) curves. We conclude that our top-gate ZnO-TFT is a unique test bed for confirming and validating the C-V results for the work function measurement of any metal electrodes.
Electron confinement in a metal nanodot monolayer embedded in silicon dioxide produced using ferritin protein
Authors: Hikono Takio , Matsumura Takashi , Miura Atsushi , Uraoka Yukiharu , Fuyuki Takashi , Takeguchi Masaki , Yoshii Shigeo , Yamashita Ichiro
Published: January 2006

A metal-oxide-semiconductor (MOS) structure with a buried monolayer of ferritin cores in the SiO2 layer was fabricated and the electron confinement in the cores was confirmed. A monolayer of ferritin molecule was adsorbed on the thermal silicon oxide layer. After the protein of the monolayer was eliminated, the ferrihydrite cores were buried in the silicon dioxide layer. We reduced the cores to conductive iron metal nanodots by low-temperature annealing. X-ray photoelectron spectroscopy and electron-energy-loss spectroscopy measurements confirmed the reduction of the cores. The MOS capacitance with the iron nanodots showed hysteresis in the capacitance-voltage measurement, indicating the charging and discharging behavior in iron nanodots.
Carbon nanotube population analysis from Raman and photoluminescence intensities
Authors: Jorio A. , Fantini C. , Pimenta M. A. , Heller D. A. , Strano M. S. , Dresselhaus M. S. , Oyama Y. , Jiang J. , Saito R.
Published: January 2006

In the absence of standard single-wall carbon nanotube samples with a well-known (n,m) population, we provide both a photoluminescence excitation (PLE) and resonance Raman scattering (RRS) analysis that together can be used to check the calculations for PLE and RRS intensities for carbon nanotubes. We compare our results with available models and show that they describe well the chirality dependence of the intensity ratio, confirming the differences between type 1 and type 2 semiconducting tubes [(2n+m)mod3]=1and2, respectively, and the existence of a node in the radial breathing mode intensity for type 2 carbon nanotubes with chiral angles between 20° and 25°.
Weak antilocalization in a polarization-doped AlxGa1−xN∕GaN heterostructure with single subband occupation
Authors: Thillosen N. , Schäpers Th. , Kaluza N. , Hardtdegen H. , Guzenko V. A.
Published: January 2006

Spin-orbit scattering in a polarization-doped Al0.30Ga0.70N∕GaN two-dimensional electron gas with one occupied subband is studied at low temperatures. At low magnetic fields weak antilocalization is observed, which proves that spin-orbit scattering occurs in the two-dimensional electron gas. From measurements at various temperatures the elastic scattering time τtr, the dephasing time τϕ, and the spin-orbit scattering time τso are extracted. Measurements in tilted magnetic fields were performed, in order to separate spin and orbital effects.
Surface potential measurements on Ni–(Al)GaN lateral Schottky junction using scanning Kelvin probe microscopy
Authors: Lian Chuanxin , Xing Huili (Grace)
Published: January 2006

The surface potential distribution across lateral Ni–(Al)GaN Schottky junctions was measured by scanning Kelvin probe microscopy. The bare surface barrier heights of unintentionally doped Al0.22Ga0.78N and n-GaN in air were estimated to be ∼1.15 and 0.7 eV, respectively. Upon 364.5 nm (band edge for GaN) illumination, the surface barriers of both n-GaN and AlGaN∕GaN were observed to decrease. The minority carrier diffusion length in n-GaN(Si∼3.5×1017cm−3) was extracted from the surface photovoltage profile near the Schottky junction, ∼1.8±0.4μm. The scanning Kelvin probe surface photovoltage technique for measuring minority carrier diffusion length, while similar to the electron beam induced current technique, offers greater accuracy and higher spatial resolution due to separation of the minority carrier excitation source (relatively large area, above band gap light beam) from the nanometer-size probe (scanning force microscope tip).
Oxygen exchange kinetics of epitaxial PrBaCo2O5+δ thin films
Authors: Kim G. , Wang S. , Jacobson A. J. , Yuan Z. , Donner W. , Chen C. L. , Reimus L. , Brodersen P. , Mims C. A.
Published: January 2006

The oxygen exchange kinetics of thin films of the oxygen-deficient double perovskite PrBaCo2O5+δ (PBCO) have been determined by electrical conductivity relaxation (ECR) and by oxygen-isotope exchange and depth profiling (IEDP). Microstructural studies indicate that the PBCO films, prepared by pulsed laser deposition, have excellent single-crystal quality and epitaxial nature. The ECR and IEDP measurements reveal that the PBCO films have high electronic conductivity and rapid surface exchange kinetics, although the ECR data indicate the presence of two distinct kinetic pathways. The rapid surface kinetics compared with those of other perovskites suggest the application of PBCO as a cathode material in intermediate-temperature solid oxide fuel cells.
Minimization of timing errors in reproduction of single flux quantum pulses
Authors: Gordeeva Anna V. , Pankratov Andrey L.
Published: January 2006

We present the analysis of the mean switching time and its standard deviation of an overdamped Josephson junction, driven by a direct current and a single flux quantum (SFQ) pulse. The performed analysis allows us to find the optimal value of the bias current of the clock generator, responsible for the shape of SFQ pulse, which minimizes noise-induced switching errors.
Terahertz dielectric properties of high-resistivity single-crystal ZnO
Authors: Azad Abul K. , Han Jiaguang , Zhang Weili
Published: January 2006

We present experimental characterization of complex dielectric properties of high-resistivity single-crystal ZnO by terahertz time-domain spectroscopy in the frequency range extending from 0.3to3.5THz. The measured refractive index, power absorption, and dielectric function are well fit by the pseudo-harmonic model of dielectric response. In addition, from the extrapolation of the experimental results, we show that the absorption is dominated by the transverse optical (TO) E1 phonon mode centered at frequency (ωTO∕2π) 12.42THz.
Microscopic analysis of optical gain in InGaN∕GaN quantum wells
Authors: Witzigmann B. , Laino V. , Luisier M. , Schwarz U. T. , Feicht G. , Wegscheider W. , Engl K. , Furitsch M. , Leber A. , Lell A. , Härle V.
Published: January 2006

A microscopic theory is used to analyze optical gain in InGaN∕GaN quantum wells (QW). Experimental data are obtained from Hakki–Paoli measurements on edge-emitting lasers for different carrier densities. The simulations are based on the solution of the quantum kinetic Maxwell–Bloch equations, including many-body effects and a self-consistent treatment of piezoelectric fields. The results confirm the validity of a QW gain description for this material system with a substantial inhomogeneous broadening due to structural variation. They also give an estimate of the nonradiative recombination rate.
Effect of hydrostatic pressure on the barrier height of Ni Schottky contacts on n-AlGaN
Authors: Liu Y. , Kauser M. Z. , Ruden P. P. , Hassan Z. , Lee Y. C. , Ng S. S. , Yam F. K.
Published: January 2006

We report measurements of the Schottky barrier height of Ni contacts on Ga-polarity n-Al0.08Ga0.92N as a function of pressure. With applied hydrostatic pressure, Al0.08Ga0.92N Schottky diodes show a decrease in the forward bias current, and correspondingly an increase in the barrier height, which is approximately twice as large as that previously reported for Schottky contacts on Ga-polarity n-GaN. The observed change in barrier height with pressure is attributed to a combination of band structure and piezoelectric effects. The larger change of barrier height for Al0.08Ga0.92N can be explained by its larger piezoelectric constants and smaller density of interface states at the metal-semiconductor interface compared to GaN.
Nitrogen incorporation characteristics on a 4H-SiC epitaxial layer
Authors: Kojima Kazutoshi , Kuroda Satoshi , Okumura Hajime , Arai Kazuo
Published: January 2006

The N incorporation characteristics on a 4H-SiC epitaxial layer were reinvestigated. It was found that the desorption process and thermally activated process are aspects of the N incorporation mechanism of 4H-SiC to which attention should be paid. This mechanism depends on both the rate-limiting condition and lattice polarity. The N desorption process dominates the N incorporation of the Si-face under the C-supply-limiting condition and that of the C-face without recourse to the rate-limiting condition. On the other hand, the thermally activated process dominates only the N incorporation of the Si-face under the Si-supply-limiting condition. The site-competition phenomenon was also found to depend on the rate-limiting condition.
Quantum point-contact switches using silver particles
Authors: Akai-Kasaya M. , Nishihara K. , Saito A. , Kuwahara Y. , Aono M.
Published: January 2006

We have demonstrated a switching system with a quantized point contact using the silver particle motion. By applying appropriate bias voltages, the silver particles that are positioned between a scanning tunneling microscope tip and a substrate stick and unstick to the tip. The minute motion of the particles is induced by sum of two Coulomb interactions. The typical conductance of the contact formed is constant, which shows low integral multiples of quantized conductance. Reproducible switching cycles of the contact are achieved using continuous multiple square voltage pulses with a frequency up to 40kHz.
Effects of predation and rabbit haemorrhagic disease on population dynamics of rabbits (Oryctolagus cuniculus) in North Canterbury, New Zealand
Authors: Reddiex Ben , Hickling Graham J. , Norbury Grant L. , Frampton Chris M.
Published: January 2006

The impact of predation and rabbit haemorrhagic disease (RHD) on population dynamics of rabbits, and the survival of juvenile rabbits, was investigated between July 1999 and March 2000 in North Canterbury, New Zealand. Rabbit abundance and pre- and post-emergent rabbit mortality were monitored on four sites, two of which were subject to predator control. RHD spread naturally through all sites from late November to early December. Rabbit densities declined on all sites, but after the RHD epidemic, declines were significantly greater where populations of predators had not been controlled. Survival of rabbit nestlings was lower where predators were not controlled. All post-emergent radio-collared rabbits died at sites where predators were not controlled, whereas 18% of those collared at sites where predators were controlled survived to maturity. In contrast to the results from previous studies, rabbits born at the start of the breeding season had very high rates of post-emergent mortality, as they appeared to be susceptible to the RHD virus later in the breeding season. The age at which juvenile rabbits become susceptible to RHD, the timing of RHD epidemics, and the abundance of predators are likely to be important in determining survival of juvenile rabbits. This study demonstrates that predation can reduce rabbit populations to low levels, but only in combination with other factors, in this case RHD.
Rabbit haemorrhagic disease: does a pre-existing RHDV-like virus reduce the effectiveness of RHD as a biological control in Australia?
Authors: Cooke B. D. , McPhee S. , Robinson A. J. , Capucci L.
Published: January 2006

Serological data from wild rabbits support the hypothesis that a second RHDV-like virus was already present in Australia before rabbit haemorrhagic disease virus (RHDV) was introduced as a biological control agent. This putative virus apparently persists in most wild rabbit populations in the presence of RHDV, and antibodies raised against it appear to protect some rabbits from fatal rabbit haemorrhagic disease (RHD). High titres of these antibodies are most commonly found in rabbits from high rainfall areas; this may explain why the initial mortality from RHD declined as the disease spread from dry areas into wetter regions and why it remains less effective as a biological control in wetter regions today. The implications for further advances in rabbit control are discussed, including the need to isolate this putative RHDV-like virus and develop specific ELISA tests to facilitate its detection in the field.
Serological evidence for the presence of a calicivirus in Australian wild rabbits, Oryctolagus cuniculus, before the introduction of rabbit haemorrhagic disease virus (RHDV): its potential influence on the specificity of a competitive ELISA for RHDV
Authors: Robinson A. J. , Kirkland P. D. , Forrester R. I. , Capucci L. , Cooke B. D. , Philbey A. W.
Published: January 2006

The objective of the study was to determine for Australian wild rabbits the specificity of a competitive enzyme-linked immunosorbent assay (cELISA) developed in Italy for detecting antibodies to RHDV. Analysis of 657 sera collected before the arrival of RHDV (pre-RHD) indicated that between 17 and 38% appeared to give false positive results depending on the cut-off criteria used. The finding of pre-RHD sera reacting positively in the cELISA prompted the testing of sera in a cELISA using as antigen smooth forms of RHDV (cELISA-sf) and a solid-phase ELISA (spELISA), both of which detect reactivity to an epitope shared by the lagomorph caliciviruses. Testing of a subset of the pre-RHD sera in the cELISA-sf and the spELISA revealed that 86 and 91%, respectively, were positive. Similar results were obtained for a set of sera collected pre-RHD in the Australian Capital Territory (ACT). Sera collected from wild-stock rabbits born and raised in isolation in an animal house in the ACT were all negative in the cELISA, 6% were positive in the cELISA-sf and 13% in the spELISA. It was concluded that a calicivirus related to RHDV and European brown hare syndrome virus (EBHSV) was present in the rabbit population before the arrival of RHDV, and may still be present. The potential consequences of these findings for epidemiological studies on RHD in Australia are discussed.
Population trends in European rabbits and other wildlife of central Australia in the wake of rabbit haemorrhagic disease
Authors: Edwards G. P. , Dobbie W. , Berman D. McK.
Published: January 2006

Before the establishment of rabbit haemorrhagic disease (RHD) in central Australia in May 1996, a program was instituted to monitor its impacts at six localities broadly distributed across the region. At these sites, population trends in rabbits and other wildlife were studied over a 2.5-year period. Rabbit populations declined by approximately 85% following establishment of RHD at the sites, and had not recovered 22 months later. More varanid lizards were detected on our survey plots 12–22 months after RHD than during the preceding period. Although numbers of dingoes and wedge-tailed eagles varied during the study, significant population reductions were not detected in either species in the wake of RHD. Significant population changes were not detected in red foxes, feral cats, red kangaroos, small mammals, or other raptor species.
Impact of rabbit haemorrhagic disease on introduced predators in the Flinders Ranges, South Australia
Authors: Holden C. , Mutze G.
Published: January 2006

The impact of rabbit haemorrhagic disease (RHD) on the population dynamics and diet of foxes and feral cats was studied in the Flinders Ranges, South Australia. Populations of both foxes and cats decreased substantially some 6–10 months after the advent of RHD, when rabbit numbers were reduced by 85%. The diet of foxes changed as a result of reduced rabbit numbers, with much less rabbit and more invertebrates and carrion being eaten. The physical condition of foxes showed little change after RHD. The diet of cats did not change markedly, but their physical condition was substantially poorer than before RHD. Total predation on native fauna is considered to have decreased after RHD.
Development of the bridled nailtail wallaby, Onychogalea fraenata, and age estimation of the pouch young
Authors: Johnson P. M. , Hendrikz J. K.
Published: January 2006

Morphological growth and qualitative development of the pouch young of captive
Onychogalea fraenata are described from birth to
permanent pouch emergence. Intuitively, age is a determining factor of growth
and development, which precludes it from being the regressand in regression
analysis. Therefore, age prediction can only be achieved by estimating
expected growth for various ages and examining the confidence limits to this
growth. Age values corresponding to these confidence limits are derived from
the growth equations and used as limits for the ages. On the basis of these
intervals the reliability of age predictions, for ages measured in different
day-based units can be assessed. A statistical method is selected so that a
small amount of irregularity in the frequency of measurement can be tolerated,
and accounted for, in the model, as well taking into account inter-animal
variation in growth parameters.
Ecology of Australian tropical rainforest mammals. I. The Cape York antechinus, Antechinus leo (Dasyuridae : Marsupialia)
Authors: Leung Luke K.-P.
Published: January 2006

This is the first detailed ecological study of the Cape York antechinus,
Antechinus leo, a small marsupial endemic to rainforest
on the Cape York Peninsula, North Queensland, Australia. A total of 181
animals was captured 725 times at Iron Range during a
capture–mark–recapture study from 1989 to 1991.
A. leo is crepuscular–nocturnal, insectivorous,
semi-arboreal and nests in hollows. Its life-history strategy is typical of
the genus, including the synchrony of reproductive events and the post-mating
death of all males. The estimated annual mating season is from mid-September
to mid-October. Young were born around 1 November ( 12 days), and were carried
in the pouch until early to mid December. Juveniles became trappable around
mid February. Daughters stayed in their mother’s home range, while sons
dispersed soon after they left the nest. Lactation, weaning and dispersal of
young were timed to coincide with the wet season when the abundance of
invertebrates increased, suggesting that populations are limited by food
supply.
Ecology of Australian tropical rainforest mammals. II. The Cape York melomys, Melomys capensis (Muridae : Rodentia)
Authors: Leung Luke K.-P.
Published: January 2006

This is the first detailed ecological study of the Cape York melomys,
Melomys capensis, a small rodent endemic to the Cape
York Peninsula, North Queensland, Australia. A total of 343 animals was
captured 781 times in rainforest at Iron Range during a
capture–mark–recapture study from 1989 to 1991. Compared with
other species of Melomys in more variable habitats,
populations of M. capensis were relatively stable:
adjusted mean number on the traplines exhibited a maximum 1.3–2.0-fold
difference. The stable demography may be related to the apparently more
constant food supply in tropical rainforest. Both population abundance and
male reproductive condition peaked in December when the availability of fruit
was high, indicating that populations are limited by food supply.
M. capensis was herbivorous, nocturnal, semi-arboreal,
and it nested in hollows. Breeding occurred throughout the study. Most litters
comprised two young. Young became trappable at about 14 days of age, and
reached reproductive maturity at about 43 days of age. Females gave birth to
the first litter when they were at least 80 days old and continued to breed
into their second year.
Ecology of Australian tropical rainforest mammals. III. The Cape York rat, Rattus leucopus (Muridae : Rodentia)
Authors: Leung Luke K.-P. , Leung Luke K.-P.
Published: January 2006

This is the first detailed ecological study of the Cape York rat,
Rattus leucopus, a small rodent found on the Cape York
Peninsula, North Queensland, Australia. A total of 296 animals was captured
1135 times in rainforest at Iron Range during a
capture–mark–recapture study from 1989 to 1991. Compared with
other native species of Rattus in more variable
habitats, populations of R. leucopus were relatively
stable: adjusted mean numbers on the traplines exhibited a 2.3–2.6-fold
change. This stability may be related to the apparently more stable food
supply in tropical rainforest. Evidence from this study indicates that
populations are limited by food availability: male reproductive condition
peaked in December when fruit availability was high; and mean population
abundance significantly increased in moist areas where food supply was
apparently higher.
R. leucopus was nocturnal, terrestrial, omnivorous, and
nested communally in burrows. Breeding occurred throughout the study. Young
became trappable at the age of 22 days. Reproductive maturity was reached at
the age of three months. Females gave birth to their first litters when they
were at least four months old, and continued to breed into their second or
third year.
Waterbird abundance in eastern Australia, 1983 - 92
Authors: Kingsford R. T. , Wong P. S. , Braithwaite L. W. , Maher M. T.
Published: January 2006

We examined the relationships between abundance of 16 species of waterbirds
and the rainfall in eastern Australia, the rainfall west of this region, the
annual Southern Oscillation index (SOI), the wetland area, and hunting in
eastern Australia for the period 1983–92. Data were collected during
aerial surveys of eastern Australia. For most explanatory variables, lags of
up to five years before aerial surveys were also investigated during these
analyses. The analyses covered all nine game species (plumed whistling-duck,
Australian shelduck, Australian wood duck, pink-eared duck, grey teal,
chestnut teal, Pacific black duck, Australasian shoveler, hardhead) and seven
non-game species (Australian pelican, white-faced heron, yellow-billed
spoonbill, freckled duck, black swan, black-winged stilt, red-necked avocet).
Regression models were developed for all species apart from Australian
pelicans. Rainfall and climate indices generally were most correlated with the
species’ abundance. Bonferroni adjustments to significance levels meant
that there were significant variables in regression models for seven of the 16
species. Abundance indices for plumed whistling-duck, chestnut teal, hardhead,
black swan and black-winged stilt were related to the climate variables
(rainfall, SOI) and wetland area, whereas abundance of pink-eared duck and
red-necked avocets were negatively related. Abundance of chestnut teal was
positively related to numbers of hunting licences sold. The results are
equivocal about the role of hunting in determining waterfowl abundance, which
is probably a reflection of few data points and numbers of variables included.
In general, abundance indices of waterbirds appear to have decreased between
1983 and 1992, which may correspond to other factors not modelled
Demography and home range of the eastern barred bandicoot (Perameles gunnii) in south-eastern Tasmania
Authors: Mallick Stephen A. , Driessen Michael M. , Hocking Gregory J.
Published: January 2006

We used live-trapping to study the demography and movement of two populations
of the eastern barred bandicoot, Perameles gunnii, in
south-eastern Tasmania from 1992 to 1996. Densities were 0.35–2.35
animals ha–1. Sex ratios were male-dominated on
Grid I and female-dominated on Grid II. The average body weight for sexual
maturity was 700g for males and 680g for females, while the lowest recorded
weight for a breeding female was 570g. Perameles gunnii
was sexually dimorphic, with males having a greater body weight and pes length
than females. Recruitment was 25.4–32.1%, residence
46.7–100.0%, and emigration 16.5–25.5% of the
population. Three juveniles were recruited to the Grid I population, 55 to
Grid II, with a steady decline in the number of juveniles recruited to Grid II
over the four years of the study. Breeding occurred year-round. Mean litter
size was 2.53, with 78.2% of all litters having either 2 or 3 young.
Mean longevity for male and female P. gunnii was 7.91
and 10.54 months, respectively. Home ranges of males (4.29 ha) were
significantly larger than those of females (2.34 ha), although this may
represent a significant underestimate due to the small width of our grids
(200m) relative to the home-range area. There was only moderate overlap
(19.3%) between home ranges of males and females. The overlap between
male/male home ranges (4.4%) was significantly less than the
overlap between female/female home ranges (15.8%).
Perameles gunnii carried both ticks and fleas, with flea
infestation being significantly higher on Grid I than on Grid II.
Both populations underwent a significant decline over the study period,
apparently the result of the unusually dry conditions over the first 3 years
of the study. A deterioration in conditions was associated with a steady loss
of resident adults, declining recruitment of juveniles and an increase in the
male/female sex ratio. The sex ratio of P. gunnii
populations may provide a convenient index of habitat quality, with poor or
deteriorating conditions apparently associated with a high or increasing
numbers of males to females.
The dietary ecology of Australian rodents
Authors: Murray B. R. , Dickman C. R. , Watts C. H. S. , Morton S. R.
Published: January 2006

Very little systematic information has been collected on the diets of
Australian rodents in arid and semiarid regions. The information that is
available is restricted generally to short periods of sampling and small
sample sizes. Here we review the diets of 15 extant and one extinct species of
Australian desert rodents, and provide new results of dietary analyses for (1)
Leggadina forresti,
Pseudomys desertorand
Rattus villosissimus from the Simpson Desert,
south-western Queensland, (2) P. albocinereus and
P. bolami from the western goldfields of Western
Australia, and (3) Notomys alexis,
P. desertor and
P. hermannsburgensis from the Tanami Desert, Northern
Territory. Overwhelmingly, omnivory is the predominant dietary strategy, with
most species (11) taking substantial amounts of invertebrate, seed and green
plant material. Of the other five species, four can be considered herbivores
and one a granivore. Of the four herbivores, however, one is extinct
(Leporillus apicalis), one is restricted to an offshore
island (Lep. conditor), while another
(P. fieldi) is classified as a herbivore from a diet
sample of four individuals only. Similarly,
P. occidentalis is classified as a granivore on the
basis of dietary sampling of two individuals alone. These findings indicate
that omnivory, over and above any other dietary strategy including granivory,
is predominant among rodents inhabiting Australian deserts.
The distribution, ecology and current status of Pseudomys desertor in South Australia
Authors: Read J. , Copley P. , Bird P.
Published: January 2006

Recent surveys have shown that the desert mouse
(Pseudomys desertor), which was once considered to be
rare in South Australia, is relatively widespread throughout the north-west of
the State. However, historical localities in the Flinders Ranges and Nullarbor
Plain were not matched with contemporary records, suggesting a range
contraction to the central desert regions. Habitat preferences were determined
from 78 captures at 41 sites, which revealed that samphire, sedge and
nitrebush habitats, along with spinifex grassland, were favoured. A high
tolerance to high rabbit numbers, mining activity, moderate cattle grazing
pressures and cohabitation with Mus domesticus was
evident.
Pseudomys desertor is sometimes diurnal, possibly as a
result of the time-consuming and regular foraging requirements of its
folivorous diet. High mortality rates, resulting from prolonged exposure to
predators, and lack of complex deep burrow systems are offset by its high
fecundity and ecological plasticity. We consider that
P. desertor is secure in the north-western arid zone of
South Australia.
The distribution, habitat requirements and conservation status of the plains rat, Pseudomys australis (Rodentia : Muridae)
Authors: Brandle R. , Moseby K. E. , Adams M.
Published: January 2006

Species in the Pseudomys australis complex were
historically widely distributed in a variety of habitats over southern
Australia. By 1990 the group had apparently declined to a single species in
the centre of its former range in the north-western Lake Eyre Basin, in gibber
plain areas. In the past, the species has been collected only after
exceptional annual rainfall. This study sought to define the current
distribution of P. australis and to determine its
preferred habitats during the usual prolonged dry periods. Allozyme
electrophoresis on blood and tissue samples were used to investigate the
genetic distinctiveness of geographically separated populations. The known
distribution has been extended along a belt of gibber habitats running from
north-west of Lake Eyre on the Northern Territory border to south of Lake Eyre
South, and a discrete population inhabiting gibber tableland west of Lake
Torrens. Pseudomys australis was extant in low-lying
patches of deep cracking clay associated with minor drainage features and
small depressions of cracking clay ‘gilgai’ common on some gibber
plains. The former type sustained significantly denser populations, which we
suggest represent ‘source’ habitats or ‘refugia’
during droughts. Many of the 16 localities at which the species was recorded
are geographically separated; however, electrophoretic analyses showed high
levels of allozyme heterozygosity and no evidence of speciation.
The diet of the New Holland mouse, Pseudomys novaehollandiae (Waterhouse) in Victoria
Authors: Wilson B. A. , Bradtke E.
Published: January 2006

The New Holland mouse (Pseudomys novaehollandiae) is
found in disjunct populations in coastal south- eastern Australia. This study
assessed the diet of the species at four locations (Anglesea, Loch Sport,
Providence Ponds and Wilsons Promontory) in Victoria, southern Australia,
where it is very rare in abundance and distribution. Overall,
P. novaehollandiae was found to consume considerable
amounts of dicotyledon leaf (27%), fungi (19%), invertebrate
(17%) and seed (14%). There was no significant difference in
diet between males and females. Seasonal variations in the percentage of
dicotyledon leaf and fungi consumed were recorded. There were also significant
differences between localities in the consumption of fungi, root and
invertebrate material. Dicotyledon leaf was the most commonly consumed food
item at Anglesea, Providence Ponds and Wilsons Promontory, while fungi was the
most important at Loch Sport. The dietary differences between localities are
likely to be related to important habitat factors including vegetation
floristics and successional age. The results indicate that
P. novaehollandiae is an omnivore with an opportunistic
foraging strategy.
Analysis of the impact of stoats, Mustela erminea, on northern brown kiwi, Apteryx mantelli, in New Zealand
Authors: Basse B. , McLennan J. A. , Wake G. C.
Published: January 2006

An age-structured population analysis is used to determine recruitment levels
and a condition for survival which can assist management decisions and hence
improve the viability of populations of northern brown kiwi,
Apteryx mantelli, in forests on the New Zealand
mainland. Currently, in the absence of predator control, recruitment rates are
less than 5% due to high levels of stoat,
Mustela erminea, predation on juvenile kiwi. Predation
levels on adult kiwi are very low. The analysis predicts that a recruitment
rate of 19% is required to maintain population stability. To achieve
this target, stoat populations have to be reduced by about 80% in some
years, and maintained at a critical residual density estimated to be a value
less than two animals per square kilometre for up to nine months until
immature kiwi reach a safe size of about 1200 g (50% of their adult
weight). Recent predator-control initiatives indicate that stoat numbers can
be reduced and maintained at low levels in relatively small areas of mainland
forest (up to 1000 ha). New techniques are needed to protect kiwi over larger
areas.
Population ecology of the Australian frog Crinia signifera: larvae
Authors: Williamson I. , Bull C. M.
Published: January 2006

There are few published studies of the population ecology of the larvae of
Australian native anurans. In this study we report on the population dynamics
of the larvae of the Australian frog Crinia signifera at
a study site near Bridgewater in the Adelaide Hills, South Australia. The
predator community was also monitored to provide an indication of the
importance of predation in influencing the population dynamics of
C. signifera larvae. Pool drying meant larvae failed to
metamorphose from temporary pools in all years of the study. In a permanent
pond, mortality was high and variable, with an average of 10% survival
over the three years of the study. There was a complete failure to recruit to
the terrestrial phase in one year. Predation pressure was thought to be the
most important source of mortality in the permanent pond, although predator
numbers varied considerably between and within years. When combined with
information on the population ecology of the embryonic (Williamson and Bull
1994) and terrestrial (Williamson and Bull 1996) stages, the data suggest that
the aquatic phase is the key phase in the population dynamics of this species.
Counting cassowaries: what does cassowary sign reveal about their abundance?
Authors: Westcott David A.
Published: January 2006

The use of surveys of sign (e.g. dung, tracks and sightings) to estimate
abundance is a method in common usage with a variety of vertebrates,
especially forest species and those with cryptic habits. Particularly for
endangered species, such as the southern cassowary,
Casuarius casuarius, the resulting abundance estimates,
at both regional and local scales, can be fundamental to management and
conservation decisions. Current estimates of regional cassowary abundance in
North Queensland are based on the results of surveys that documented
indicators of cassowary activity across the Wet Tropics Region. When applied
to population abundance estimation this approach assumes (i) that cassowary
sign is as likely to be encountered on trails as it is in the forest
generally, and (ii) that there is a relationship between the amount of
cassowary sign encountered and the number of birds using a trail. These
assumptions were tested in a project conducted in Wooroonooran National Park,
north Queensland. In failing to support either assumption, the fieldwork
identified the need for the improvement of large-scale survey techniques for
cassowaries, and for caution in the application of this method and the
interpretation of its results more generally. In the case of cassowaries,
improvements to the current method could be achieved by incorporating multiple
surveys at each site, assessment of local use of trails by cassowaries and of
fruit abundance at the time of surveying.
Assessment of the M-44 ejector for the delivery of 1080 for red fox (Vulpes vulpes) control
Authors: Marks Clive A. , Busana Frank , Gigliotti Frank
Published: January 2006

The M-44 ejector delivered a reliable lethal dose of 1080 (sodium
monofluoroacetate) to captive foxes, with a capsule dose of 2.0 mg of 1080, if
a ‘collar’ modification was used. Behavioural observations
indicated that the collar influenced the orientation of the fox’s mouth
to the M-44 bait upon activation, resulting in a much greater amount of 1080
entering its mouth. This dose is below the 3 mg currently used in fox baits in
Victoria and may increase the margin of safety for non-target species during
1080 baiting programs. The authors discuss some of the potential advantages of
the ejector over the use of meat baits, such as the elimination of bait
caching and improved target specificity. The potential for the M-44 to deliver
an even lower lethal dose of 1080, which is closer to the reported theoretical
bait LD100 of 1.25 mg for this species, may further
reduce the risk of 1080 baiting to non-target species such as tiger quolls.
Home range and habitat use by Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi) within a rainforest fragment in north Queensland
Authors: Newell Graeme R.
Published: January 2006

Lumholtz’s tree-kangaroo (Dendrolagus lumholtzi),
one the largest arboreal mammals in Australia, has been poorly studied owing
to its limited distributional range and secretive habits within tropical
rainforests. This study investigated the way
D. lumholtzi used its habitat within a rainforest
fragment on the Atherton Tableland, North Queensland. Thirteen animals were
fitted with radio-collars to determine their spatial and temporal use of
habitat. Female D. lumholtzi used exclusive home ranges
averaging 0.7 ha in area (90% harmonic mean), while males occupied
larger home ranges of an average of approximately 2 ha, allowing for a density
of 1.4–1.5 adult tree-kangaroos per hectare within the study area. The
exception to this home- range size was one juvenile male presumably undergoing
post-natal dispersal that used several forest fragments and other habitats,
with a home range of 332 ha. Home ranges of males overlapped in part the
ranges of several females. Home ranges of males tended to abut those of other
males, and antagonistic encounters occurred at the boundaries of the home
ranges. Males had a significantly larger body size than females (males 8.63
kg; females 7.05 kg). Social interactions between individuals, apart from
antagonistic male–male encounters, were observed infrequently. Only
6% and 2.7% of fixes for females and males, respectively,
included the presence of another animal in the same or adjacent tree at the
time of location. Lumholtz’s tree-kangaroos were associated with a wide
range of rainforest trees and a smaller number of vine species. However, in
general, individual animals regularly associated with only a small suite (mean
3.5 species with >10% usage) of tree species present within their
home range, and appeared to display individual preferences for certain
species. Individual radio-tracked D. lumholtzi were
visible only 9.4% of the time at night, and 20% of the time
during the day. Males and females were as visible as each other, and both were
seen significantly lower in the canopy and into the mid-storey during the
night than during the day.
Non-target mortalities during aerial strychnine baiting of house mice
Authors: Brown Peter R. , Lundie-Jenkins Geoff
Published: January 2006

The effect of strychnine baiting on non-target bird species was investigated
in Queensland, Australia, during August and September 1995. Strychnine was
aerially applied to 250 000 ha of crop to control high densities of mice.
Searching for bird carcasses was conducted in two regions. A sample of the
birds collected was chemically tested for the presence of strychnine and other
poisons. We attributed strychnine poisoning to 117 of 157 birds found. The
proportions of birds of each major feeding group that tested positive to
strychnine were 82.2% for granivores, 55.5% for raptors, and
69.3% for omnivores. Most bird carcasses (80%) were found on the
edge of the baited crop or within 10 m of the edge of the crop. Of the 11
birds analysed quantitatively, the average level of strychnine in the liver,
gizzard and crop was 10.80 µg g-1 (± 5.77
s.e., n = 7), 77.30 µg
g-1 (± 42.41 s.e., n
= 10) and 372.17 µg g-1 (± 334.59
s.e., n = 3) respectively. Significantly more
poisoned birds were found per hour of search time around the wooded
Goondiwindi area (15 birds: 0.71 birds per hour) than around the open Dalby
area (12 birds: 0.08 birds per hour)
(χ21 = 28.42,
P < 0.001). Our results show that non-target deaths
occurred with strychnine baiting. To reduce these deaths we recommend that:
(i) the baited buffer zone around the edge of baited crops be set at 50 m;
(ii) no areas of bare ground should be baited; and (iii) baiting should not
occur if there is a chance that bait will remain on the ground for more than
seven days.
Long-term dynamics of a rodent community in an Australian tropical rainforest
Authors: Heinsohn George , Heinsohn Robert
Published: January 2006

We report on a long-term population study (started in 1969) of three sympatric
rodent species in a tropical Queensland (Australia) rainforest. Populations
were censused annually using live-trapping and individual marking on two grids
in different habitat types. Two of the species,
Melomys cervinipes and
Uromys caudimaculatus, are ‘old endemics’
and have slower life-histories than the third species,
Rattus fuscipes, which invaded Australia more recently.
The numbers of all three species fluctuated markedly over the study period.
Rattus numbers started low, peaked in the early 1980s,
and then crashed to zero by 1993. In contrast, Melomys
climbed gradually throughout the study period but crashed to zero by 1996.
Melomys numbers increased in drier years whereas
Uromys numbers decreased, but these results were
confounded by autocorrelation over time. When the effects of time (year of
study) were removed statistically, the correlations with rainfall disappeared,
but the number of Rattus remained negatively correlated
with the number of Melomys on one grid. We discuss the
possibility that numbers of these two species are determined by a combination
of climate and interspecific competition.
Feeding behaviour of the yellow-bellied glider (Petaurus australis) at the western edge of its range
Authors: Carthew Susan M. , Goldingay Ross L. , Funnell Darryl L.
Published: January 2006

This study provides the first assessment of the diet of the yellow-bellied
glider (Petaurus australis) in the south-west portion of
its range near the Victorian–South Australian border. Examining its diet
in this region is viewed as being fundamental to understanding the ecological
requirements of the species. Observations were conducted over a five-year
period on gliders from five distinct groups. Sap was the most important food
item throughout the year and accounted for 83% of 407 feeding
observations. Each group of gliders used up to 21 different trees for sap, but
during any sample period only 1–8 trees were used. This represents a
vastly different pattern of use of sap trees to that described in any earlier
study. Some trees were visited more often than others, and these tended to be
heavily scarred, indicating use over many years. Other food types were
arthropods and honeydew and, to a lesser extent, nectar. This study also
revealed that the yellow- bellied glider is not dependent on a diversity of
tree species nor on a winter-flowering species. We provide a review of the
diet of the yellow-bellied glider throughout its range. This shows that the
yellow-bellied glider is reliant on sap as a food resource but particularly so
at both ends of its geographic range. The reason for this is unclear, but
there is definitely a need for further study of sap-flow patterns in
eucalypts.
The short-term effect of cane toads (Bufo marinus) on native fauna in the Gulf Country of the Northern Territory
Authors: Catling P. C. , Hertog A. , Burt R. J. , Forrester R. I. , Wombey J. C.
Published: January 2006

The range of the cane toad has expanded rapidly in the Northern Territory, and
there is growing concern that the species may have a detrimental effect on the
native fauna. The aim of this study, therefore, was to determine the
short-term effects of cane toads on populations of native fauna and,
specifically, to compare the species diversity and relative abundance of
native fauna before, during and after the invasion of an area by cane toads.
Five major groups of fauna (wingless invertebrates, amphibians, reptiles,
birds and mammals) were sampled over two years.
The study has provided little evidence that cane toads have a significant
adverse effect in the short-term on the diversity and abundance of the native
fauna examined. However, there was an indication that there may be a long-term
indirect effect on some fauna. In the short-term the dingo
(Canis lupus dingo) and one Order of insect (Coleoptera)
were affected negatively. The possible long-term negative effect was on the
small reptile fauna and particularly the small skinks. This may be an indirect
effect on their food supply, because the groups affected were those that were
considered neither to ingest cane toads nor to be eaten by cane toads.