bluuebunny/crossref_metadata_2025 huggingface dataset:
Toward a framework for runoff and soil loss prediction using GUEST technology
Authors: Yu B. , Rose C. W. , Ciesiolka C. A. A. , Coughlan K. J. , Fentie B.
Published: August 2004

In recent years, a number of physically based models have been developed for
soil loss predictions. GUEST is one such model based on fundamental physical
principles and the current understanding of water erosion processes. GUEST is
mainly used to determine a soil erodibility parameter. To apply the model in a
predictive mode, the model is simplified in a physically meaningful manner for
flow-driven erosion processes, and 2 essential hydrologic variables are
identified, namely total runoff amount and an effective runoff rate. These
variables are required to determine soil loss for individual runoff events. A
simple water balance model was developed and used to predict runoff amount
from rainfall amount. The efficiency of this runoff amount model in prediction
was over 90% using field data. A 1-parameter regression model
(r2 ~ 0·9) for the
effective runoff rate was also established which uses peak rainfall intensity
in addition to rainfall and runoff amounts. The prediction of peak rainfall
intensity for a given rainfall amount and storm type was also sought. The
field data were from Goomboorian, near Gympie, in south-east Queensland and
these data were used to test and validate both models. Results overall are
satisfactory and the approach adopted is promising. A framework for soil loss
prediction is established within which individual parts can be further refined
and improved.
Temporal variation in soil acidity
Authors: Conyers M. K. , Uren N. C. , Helyar K. R. , Poile G. J. , Cullis B. R.
Published: August 2004

Seasonal variation in the response of crops and pastures to limestone
application has been observed on acidic soils in south-eastern Australia. Our
hypothesis was that temporal variation in soil acidity related factors may
contribute to this variable response. Soils from 4 annual pasture sites were
sampled at least monthly for 3 years during 1988–1990 to monitor changes
in pH(CaCl2) and in concentrations of exchangeable
aluminium (Al) and manganese (Mn). The sites received no fertiliser or
cultivation and therefore allowed for the estimation of natural temporal
variation.
Temporal variation in soil pH during a year ranged from 0 to 0·45 pH
units depending on the site, soil depth, and the weather conditions. The
larger changes in soil pH were associated with more extreme climatic
conditions than normal, e.g. following the break of season after a hot, dry
summer (autumn 1988) or during periods of above-average rainfall in autumn and
early spring (1990). Temporal variation in pH was less than the spatial
variability at the sites but greater than the long-term net acidification rate
reported for the region.
Temporal variation in the concentration of exchangeable Al ranged from 0 to
0·4 cmol(+)/kg during a year and varied primarily with the
inverse of pH. Variations in the concentration of exchangeable Mn ranged from
0·05 to 0·35 cmol(+)/kg during a year. The
concentration of exchangeable Mn increased over summer to an extent dependent
on the drying of the soil. At the 2 sites with duplex profiles, maxima in the
concentration of exchangeable Mn also occurred in spring, particularly in the
warm wet spring of 1990.
Soil tests for soil acidity therefore represent guides to probable risks of
toxicity, as pH and the concentrations of exchangeable Al and Mn may change
between soil sampling, sowing, and the period of crop or annual pasture
growth. Such variations will alter the responsiveness of crops and pastures to
lime.
Nitrogen distribution in soil density fractions and its relation to nitrogen mineralisation under different tillage systems
Authors: Alvarez R. , Alvarez C. R. , Daniel P. E. , Richter V. , Blotta L.
Published: August 2004

Cropping leads to a depletion of soil organic matter which is associated with
a decrease in crop yields. In order to reduce land degradation, conservation
tillage systems have been developed over the last few decades. We evaluated
the effects of 12 years of no-tillage, chisel tillage, and plough tillage, in
a Typic Argiudoll from the Argentine Pampa, on nitrogen distribution in the
light (<1·6 g/mL), medium (1·6–2·0
g/mL), and heavy (>2·0 g/mL) soil density fractions and its
mineralisation potential. Under no-tillage, nitrogen in light and heavy
fractions, and mineralised nitrogen of the whole soil, diminished markedly
with depth. Meanwhile, in ploughed soil these variables remained constant up
to 20 cm depth. Under chisel tillage, an intermediate condition was observed.
In the first 20 cm, no-tillage accumulated more nitrogen in light and medium
fractions. A higher and positive correlation was observed between the
percentage of organic nitrogen mineralised and the nitrogen in the soil medium
fraction, as a percentage of the total nitrogen. Cumulative nitrogen
production fitted significantly to the exponential
(R2 > 0·931), hyperbolic
(R2 > 0·932), and
logistic (R2 > 0·930)
models, while the Gompertz equation described the data best, obtaining the
highest determination coefficient
(R2 > 0·989).
In vitro nitrogen mineralisation was highest under
no-tillage. These results could be attributed to the accumulation of labile
organic components associated with a lower mineralisation intensity in the
field, a consequence of lower temperatures. This increase under no-tillage in
fertility can represent a nitrogen reserve for future crops.
Comparative effects of subterranean clover, medic, lucerne, and chickpea in wheat rotations, on nitrogen, organic carbon, and moisture in two contrasting soils
Authors: Holford I. C. R. , Schweitzer B. E. , Crocker G. J.
Published: August 2004

The effects of subterranean clover, medic, and lucerne, grown simultaneously
from 1988 to 1990, followed by wheat from 1991 to 1993, and of chickpea and
long fallow in alternate years with wheat, on soil total nitrogen (N),
nitrate-N (NO-3-N), organic carbon
(C), and moisture were measured over 6 years in 2 long-term experiments on a
black earth (pellic vertisol) and red clay (chromic vertisol) in northern New
South Wales.
The accretion of soil total N in the black earth and
NO-3-N in both soils was higher
after lucerne than after other legumes, and
NO-3 in the black earth remained
high after lucerne to the full depth (120 cm) of measurement during the
following 3 years of wheat growing. Clover had the next largest effect on
total N and NO-3 accretion, and
chickpea had the smallest effect except in the red clay where chickpea
increased NO-3 more than medic in
1990. However, none of the annual legumes had much effect on
NO-3 after the first year of
cropping and their small residual effects, if any, were confined to the top 30
cm of soil. Levels of total N accretion after lucerne were higher than
previously measured, because of the greater depth of measurement, but were
similar on a per unit depth basis.
High levels of NO-3 -N after long
fallow, especially in the black earth, which tended to be higher than after
medic or chickpea, were probably caused by accelerated mineralisation of
organic N which has declined more in this rotation than in any other.
There was no accumulation of organic C during the legume growing period in any
rotation, and C tended to be lower after chickpea than after other legumes.
Organic C was almost always lowest in the long fallow treatment.
Summer-growing grasses, which occurred in all treatments to varying degrees,
may have caused the organic C accumulation during the 3 years of cropping.
In the first year of wheat growing, soil water was lower after lucerne than
after other treatments and highest after long fallow, continuous wheat, and
chickpea. It was replenished in the red clay to field capacity in all
treatments by high rainfall during the fallow before the first wheat crop but
not in the black earth, which failed to reach field capacity in any treatment
even 2.5 years after the pasture legume phase.
Genesis of podzols on coastal dunes in southern Queensland. V. Chemistry and mineralogy of the non-opaque heavy mineral fraction
Authors: Chittleborough D. J. , Tejan-Kella M. S. , Fitzpatrick R. W.
Published: August 2004

Eight podzols on coastal dunes from the Cooloola chronosequence, and an
associated pedon from North Stradbroke Island (Amity), were studied to
establish (i) the degree of homogeneity of the parent
material between and within profiles, (ii) the extent of
heavy mineral weathering, and (iii) whether the parent
sediments of each pedon had a common proximate source. The pedons are
Quartzipsamments and Troporthods with ages ranging from Holocene to
Pleistocene.
On the basis of ratios zircon : rutile, zirconium : titanium, and non-magnetic
: very magnetic heavy minerals in the fine sand fraction (53–125
µm), we concluded that the parent materials of the Cooloola pedons were
mineralogically similar. By using zirconium in the non magnetic heavy mineral
fraction as an index for zircon, it is evident that there has been
considerable pedogenetic weathering of the heavy mineral fraction. There is a
statistically insignificant difference in hafnium concentrations of zircons
which implies that parent sediments of the soils at Cooloola and North
Stradbroke Island were derived from a common immediate source.
Sensitivity of selected water retention functions to compaction and inherent soil properties
Authors: Rasiah V. , Aylmore L. A. G.
Published: August 2004

It is known that field-scale variations in subsurface hydraulic
characteristics are influenced, to a large extent, by soil properties. Limited
information, however, exists on the sensitivity of hydraulic functions to
field-scale variations in soil properties. The sensitivity of 4 soil water
retention functions, θ(h), to variations in soil
properties and changes in bulk density (ρ) across and within soils along a
500-m transect has been assessed in this study. The
θ(h) functions compared are those of van Genuchten,
Brooks and Corey, Campbell, and Gardner. Water retention characteristics for 7
soils, each packed to 2 relative ρ, were established for each function.
The coefficient of determination, R
2 , for the best fit of water retention ranged from
0·79 to 0· 98 for the Gardner and Campbell functions, from
0· 92 to 0·99 for the Brooks and Corey function, and from
0·83 to 0·99 for the van Genuchten function. Simple linear
regression analysis indicated the nonlinear slope parameters of the 4
functions were more strongly correlated with soil properties. However, only
the van Genuchten slope parameters were sensitive to changes in ρ. No
consistency existed between the sensitivity of the linear parameters of the 4
functions and soil properties, and none were sensitive to changes in ρ.
Except for the a parameter in the van Genuchten function, all the parameters
in this function can be predicted with satisfactory confidence from soil
properties and ρ. The results indicate that, of the 4 functions assessed,
the van Genuchten θ(h) function is the most
sensitive to field-scale variations in soil properties along a transect in a
landscape unit and to changes in ρ.
Comparison of soil linear shrinkage curve from extracted cores and in situ
Authors: Coquet Y. , Touma J. , Boivin P.
Published: August 2004

In situ measurement of the linear shrinkage curve (LSC) of soil has been
restricted so far to highly swelling clay soils because of the limited
precision of thickness measurements of the soil layer. This limitation was
eliminated by using electronic displacement transducers that allowed a
precision of ±10 µ m on the thickness measurements of 20-cm soil
layers. The method was further improved by using block kriging to estimate
non-destructively and locally the water content of the soil layer at the same
spot where the shrinkage was monitored by the shrinkfiswell gauge.
The LSC of 2 weakly swelling soils measured by this method had a shape similar
to that of highly swelling soils, although their shrinkage range was 2 orders
of magnitude smaller.In situ LSCs of the soil layers
were compared with the LSCs of extracted soil cores measured in the
laboratory. In situ and laboratory shrinkage curves were significantly
different. This discrepancy is thought to be principally due to the rewetting
of the soil cores in the laboratory before the shrinkage curve measurement
without any mechanical stress applied to their external surfaces.
The influence of the soil matrix on nitrogen mineralisation and nitrification. I. Spatial variation and a hierarchy of soil properties
Authors: Strong D. T. , Sale P. W. G. , Helyar K. R.
Published: August 2004

Natural heterogeneity of soil properties was used to explore their influence
on nitrogen (N) mineralisation and nitrification in undisturbed small soil
volumes (soil cells; c. 1 · 7
cm3 ) sampled from a small field plot (2 m by 3 m). Soil
cells (840) were randomly ascribed to 1 of 6 treatments in which soils were
retained continuously moist (M10 and
M30 treatments) and amended with organic N from clover
(Cl10 and Cl30 treatments), dried
and rewetted (DW10), or treated with urea
(Ur10) (subscripts indicate soil incubation at matric
potential - 10 or - 30 kPa). After 20 days of incubation at 24C, each soil
cell was analysed for NO-3 -N, NH
+ 4 -N, pH, bulk density (BD), volumetric water content (θv), water
content at - 490 kPa (θv490), and pH buffer capacity (pHBC). On 25 soil
cells from each treatment, % clay, % silt, % sand, total
N (% N), organic carbon (% C), and 7 cations and anions were
also determined.
Net N mineralisation and net nitrification occurred in all treatments, and the
total mineral N at the end of the incubation was 497, 81, 73, 31, 27, and 31
µg N/g in the Ur10 Cl10,
Cl30, M10,
M30, and DW10 treatments,
respectively. Net N mineralisation in the M30 treatment
was 84% of that in the M10 treatment, and net N
mineralisation in the Cl30 treatment was 86% of
that in the Cl10 treatment. Fluctuations in soil pH
varied markedly between treatments and over time, and it was apparent that
alkaline processes were occurring in all soil cells. The heterogeneity between
soil samples was substantial for all of the soil variables.
Soil variables were classified in a hierarchy from the least to the most
fundamental based on their stability through time. This ranking provides a
conceptual tool for understanding interrelationships between soil properties
and for interpreting results of regression analyses. The sampling approach
adopted in this study was designed to harness the natural heterogeneity of
soil properties in the small field site while keeping other properties and
environmental factors, that usually vary over larger distances, constant. Both
the extent of heterogeneity of soil properties and the nature of their
correlations with NO-3 -N
suggested that this technique would be useful in the exploration of how soil
properties influence N mineralisation and nitrification.
The influence of the soil matrix on nitrogen mineralisation and nitrification. II. The pore system as a framework for mapping the organisation of the soil matrix
Authors: Strong D. T. , Sale P. W. G. , Helyar K. R.
Published: August 2004

Large numbers of small undisturbed soil volumes (1·7
cm3 ) were collected from the surface layer of a 2 m by
3 m field plot on a red earth near Wagga Wagga, New South Wales. The
hypothesis tested was that an analysis of relationships between the volume of
different pore size classes and various soil properties, measured on these
soil volumes, can provide an understanding of soil organisation within the
framework of the pore system. Three discrete findings were presented in
confirmation of the hypothesis.
(1) A non-uniform distribution of organic N through the pore system was
indicated by the data analysis. Soil organic N tended to be concentrated in
pores <0·6 µm and in pores 10-30
µm, but not in the intermediate pore size class (pores 0·6-10
µm). Concentrations of organic N in pores
<0·6 µm are probably because of physical
protection from microbial decomposition, but concentrations of organic N in
pores 10-30 µm are probably because these pores
are infrequently water-filled, and this limits bacterial activity more
severely than in the pores 0·6-10 µm.
Currently available assays for potentially mineralisable N cannot account for
the effect of substrate location within the pore system, and a
characterisation of the soil for the distribution of N in pores may enhance
their utility. Soil disturbance is likely to alter organic matter distribution
through the pore system and alter mineralisation dynamics.
(2) Observations of pore size distributions before and after wetting suggested
that soils which were high in organic matter and clay tended to have a greater
volume of pores 0 ·6-30 µm which are
unstable to drying and rewetting. It is proposed that these unstable pores 0
·6-30 µm had been produced by the movement
and alignment of clay particles during the growth of microbial colonies.
(3) The volume of pores <0·6 µm had a
relatively strong negative correlation with pH and a relatively strong
positive correlation with Mn2+ . A mechanism based on
redox chemistry principles was proposed to explain these relationships. It was
suggested that the volume of pores <0·6
µm is related to the potential anaerobicity of the
soil volume. In anaerobic conditions, the terminal electron acceptor for
organic C oxidation may be MnO2 instead of
O2, and in these circumstances, considerably more
H+ would be consumed than in aerobic conditions. It is
suggested that this alkaline effect extends into regions of the matrix where N
mineralisation and nitrification are occurring, and stimulates these
processes. The greater nitrification which may result from such a chain of
events may, over time, effect greater acidification in those soil volumes
which have greater microporosity.
Effects of soil pH and applied cadmium on cadmium concentration in wheat grain
Authors: Oliver D. P. , Tiller the late K. G. , Alston A. M. , Cozens G. D. , Merry R. H.
Published: August 2004

The effects of pH and soil-applied Cd on Cd concentration in wheat grain were
determined using 4 soils in a glasshouse study. Grain Cd concentrations
increased significantly (P < 0·001) with
increasing applications of Cd for all soils. Generally, for the Alfisols the
Cd concentration in grain decreased with increasing soil pH for all Cd
treatments. The Cd concentrations in grain from plants grown on the
Haploxerert showed variable responses to pH, depending on the Cd treatment.
Smaller decreases in grain Cd concentration with increasing pH were seen on
soils with native Cd compared with grain from soils to which Cd had been
added.
Generally, Cd uptake (mg/pot) by grain grown in the Alfisols showed the
same trends with increasing pH as seen with grain Cd concentrations,
indicating no yield dilution effect. On the Bordertown soil (a Palexeralf) the
ratio of Cd in shoot material (excluding grain) to Cd concentration in grain
was found to increase significantly (P <
0·001) with increasing Cd treatments and decrease significantly
(P < 0·001) with increasing pH. The ratio on
the Bordertown soil did not remain constant across Cd or pH treatments, which
suggests that the use of soil tests to predict Cd concentration in grain may
be problematical. The transfer coefficients for Kapinnie, Freeling, and
Bordertown soils were dependent on pH, whereas that for the Inman Valley soil
was independent of pH. The relationship between the reciprocal of the
distribution coefficient (K¡ 1 d) and the transfer coefficients (Cd
grain/Cd soil) was generally good for all soils except the Vertisol from
Inman Valley.
Soil organic carbon fractions in a Vertisol under irrigated cotton production as affected by burning and incorporating cotton stubble
Authors: Conteh A. , Blair G. J. , Rochester I. J.
Published: August 2004

The contribution of cotton stubble to the soil organic matter content of
Vertisols under cotton production is not well understood. A 3-year experiment
was conducted at the Australian Cotton Research Institute to study the effects
of burning and incorporating cotton stubble on the recovery of fertiliser
nitrogen (N), lint yield, and organic matter levels. This study reports on the
changes in soil organic matter fractions as affected by burning and
incorporating cotton stubble into the soil. Soil samples collected at the
start and end of the 3-year experiment were analysed for total carbon
(CT), total N (NT), and
δ13C (a measure of
13C/12C isotopic ratios).
Labile carbon (CL) was determined by ease of oxidation
and non-labile carbon (CNL) was calculated as the
difference between CT and CL.
Based on the changes in CT, CL,
and CNL, a carbon management index (CMI) was calculated.
Further analyses were made for total polysaccharides
(PT), labile polysaccharides (PL),
and light fraction C (LF-C). Stubble management did not significantly affect
the NT content of the soil. After 3 years, the
stubble-incorporated plots had a significantly higher content of
CT, CL, and polysaccharides.
Incorporation of stubble into the soil increased the CMI by 41%,
whereas burning decreased the CMI by 6%. The amount of LF-C obtained
after 3 years in the stubble-incorporated soil was almost double that obtained
in the stubble-burnt soil. It was concluded that for sustainable management of
soil organic matter in the Vertisols used for cotton production, stubble
produced in the system should be incorporated instead of burnt.
Assessing tillage- and cropping-induced changes in relative conductivity
Authors: Rasiah V.
Published: August 2004

Although changes in relative hydraulic conductivity(Krc) in the surface soil layer can have significantimpact on transport of water and solutes below this layer, experimentaldetermination of Krc is laborious and expensive. In thisstudy, a simple theoretical equation has been used to compute near-surfaceKrc and assess its sensitivity to tillage- andcropping-induced near-surface changes in soil porosity (.epsi;), porecontinuity (PC), and soil water content (θ). The data were collected in1994 from a cropping and tillage system experiment established in 1988 on asilt loam soil. The tillage treatments were conventional and no-till. Thecropping treatments were continuous corn (Zea maize L.)under conventional cultivation (CT corn), corn following forages(alfalfa,Medicago sativa L.; and bromegrass,Bromus inermis L.) under conventional and no-till (NTcorn) practices, and continuous no-till corn. Soil bulk density (r ) and inthe near surface (depth, 0-2 ·5 cm) soil layer were measured in lateJuly 1994 subsequent to changes in tillage and cropping practices in May 1994.Only tillage differences had significant influence on ρ, θ, fractaldimension (D), PC, and Krc of the near-surface soillayer. A switch from no-till forages to CT corn resulted in increases in andD, and decreases in ρ , θ, and Krc. Theintroduction of NT corn into forage-terminated plots did not producesignificant changes in the above properties compared with continuous NT corn(7 years old), which was characterised by smaller values of and PC, and highθ and Krc. Water content, , and PC accounted for96% of the variability in Krc. The results showedthat the near-surface changes in Krc can be predictedwith high accuracy using the data on only ρ and θ which are easy togather.
Nitrate leaching from a drained, sheep-grazed pasture. II. Modelling nitrate leaching losses
Authors: White R. E. , Heng L. K. , Magesan G. N.
Published: August 2004

Nitrate (NO-3 ) concentrations in
0·5-mm increments of drainage from adjacent mole- and pipe-drained
paddocks of a silt loam soil under pasture near Palmerston North, New Zealand,
were measured during 2 winters. The data were simulated using a simple
analytical transfer function model (TFM). Urea fertiliser applied at the rate
of 120 kg N/ha to one paddock was treated as a pulse input to the pool of
resident soil NO-3. A
source{sink term was included for plant uptake and net mineralisation
(including any effect of denitrification).
During the first winter (1990), a TFM using either a 1-parameter Burns
probability density function (pdf) for solute travel, or a 2-parameter
lognormal pdf, satisfactorily simulated the
NO-3 concentration trends and
predicted the total amounts of N leached. The pdf parameters were derived from
previous chloride leaching data for this site. The best-fit value for the
transport volume θst, the key parameter in the
Burns pdf, was set at 0·37 m3
/m3 in 1990, as used in previous modelling of
sulfate leaching. However, a value of 0 ·25 m3
/m3 in the Burns pdf gave better simulations of the
1991 data. This was probably due to more intense rain events during the early
part of the drainage season in 1991 compared with 1990, which resulted in more
preferential flow through the soil and a lower value for
θst. The simulations for both years showed that
≥50% of the total leachable
NO-3 was retained in the soil,
despite normal winter drainage of about 300 mm.
Ideally, the appropriate value of st should be determined by independent
measurement. It may need to be adjusted according to the likely incidence of
preferential flow early in the winter when
NO-3 concentrations are highest.
Provided the average initial soil
NO-3 concentration can be
estimated and a net source{sink term defined, the amount of
NO-3 leached in drained soils can
be satisfactorily modelled using the TFM approach with a 1-parameter pdf.
Duplex soils which have a fluctuating watertable in the A horizon over an
impermeable B horizon may prove to be an analogous system.
A Revised Checklist of Polynesian Benthic Marine Algae
Authors: Payri Claude E. , N'Yeurt Antoine D. R.
Published: August 2004

A revised checklist of 425 taxa of benthic marine algae is provided for the
French Polynesian region, including the Society Islands, Tuamotu Archipelago,
Marquesas Islands and Austral Islands. The list comprises 117 Cyanophyceae, 42
Phaeophyceae, 96 Chlorophyceae and 170 Rhodophyceae, representing 79 new
additions to the last checklist a decade earlier. Included are all previously
published records and some yet unpublished additions, with the systematic
arrangement and nomenclature updated. The flora of Tahiti and its adjacent
islands is quite well known, whereas the one from Marquesas, Austral and
Gambier Islands have yet to be adequately examined. Also, such algal groups as
the crustose Corallinaceae are still poorly studied.
A molecular phylogeny of the grass family (Poaceae) based on the sequences of nuclear ribosomal DNA (ITS)
Authors: Hsiao C. , Jacobs S. W. L. , Chatterton N. J. , Asay K. H.
Published: August 2004

Phylogenetic relationships of the grass family inferred from the sequences of
the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA
(rDNA) are generally in accord with the boundaries of the six commonly
recognised subfamilies: Bambusoideae, Pooideae, Arundinoideae,
Centothecoideae, Chloridoideae and Panicoideae. ITS phylogeny recognises the
herbaceous bamboo allies, Streptochaeta and
Pharus, as the basal taxa to all grasses. The core grass
lineage is resolved into three major clades: the basal Bambusoideae is sister
to the monophyletic Pooideae and the
Panicoideae–Arundinoideae–Centothecoideae–Chloridoideae
(PACC) clade. Several genera with uncertain taxonomic affinities,
Lygeum, Nardus,
Brachyelytrum, Diarrhena,
Anisopogon, Ampelodesmos, and the
tribe Stipeae, are all clustered with a broadly defined Pooideae, and may be
the ‘missing links’ between the Pooideae and the Bambusoideae.
Relationships of the PACC clade indicate that C4
photosynthesis evolved independently among and within the PACC subfamilies.
ITS phylogeny of the grass family, and evidence from the chloroplast genome,
cytogenetics, fossil records, biogeography, and plate tectonic theory, suggest
that the origin of the grasses is probably ‘out of South America’.
Susceptibility of the tiger quoll, Dasyurus maculatus, and the eastern quoll, D. viverrinus, to 1080-poisoned baits in control programmes for vertebrate pests in eastern Australia
Authors: Belcher C. A.
Published: August 2004

Captive trials were undertaken to determine whether tiger quolls and eastern
quolls could detect baits that were either buried or covered with soil
following the methods employed in normal buried-poisoned-bait programmes. Both
tiger quolls and eastern quolls detected, dug up and consumed buried FOXOFF
baits. Consumption trials showed that tiger quolls were capable of consuming
2–3 FOXOFF baits in a single meal and more than three baits overnight.
Eastern quolls could consume up to 1.5 baits in a single meal.
Field trials were undertaken to investigate whether tiger quolls in the wild
could also detect and consume buried baits. Trials with both fresh meat and
FOXOFF baits were undertaken at a site near a tiger quoll latrine, using a
remote camera to record visits to the site and bait uptake. The results
confirmed that tiger quolls in the wild can detect and consume both fresh meat
and FOXOFF baits that have been buried or placed on the surface and covered
with soil to a depth of 5–8 cm.
The results indicate that the buried-bait technique is not specific for
introduced predators, and free- feeding may not preclude non-target species
from taking buried baits. Reliance on the identification of the species
visiting bait stations from tracks may also be unreliable as foxes dug up bait
stations searching for baits, even after the bait had been removed,
potentially obliterating other tracks.
Modified M-44 cyanide ejector for the baiting of red foxes (Vulpes vulpes)
Authors: Busana F. , Gigliotti F. , Marks C. A.
Published: August 2004

Fox carcasses are seldom recovered after a 1080-baiting program, making
analysis of efficacy difficult. Sodium cyanide was selected as an alternative
toxin due to its rapid mode of action. A number of bait techniques were
trialled in order to develop an appropriate cyanide delivery system that could
be used as a buried bait. Techniques investigated included treated wax and
gelatine capsules, a wooden capsule holder and a modified M-44 cyanide
ejector. Subsequent trials showed that the modified M-44 ejector had greater
efficacy in recovering fox carcasses at bait stations when compared with the
other techniques trialled. This paper describes the range of baits trialled
and the modifications that allow the M-44 to be used as a buried bait. A
protocol for deployment of the M-44 in the field, together with a brief
assessment of efficacy for each technique is also provided.
An assessment of the accuracy of kangaroo surveys using fixed-wing aircraft
Authors: Pople A. R. , Cairns S. C. , Clancy T. F. , Grigg G. C. , Beard L. A. , Southwell C. J.
Published: August 2004

The use of line-transect methodology, on foot or from a helicopter, is likely
to return the most repeatable, least biased estimates of kangaroo density.
However, the associated costs make both methods impractical for broad-scale
surveys. For these, a fixed-wing aircraft remains the most cost-effective
platform. Limitations of the standard fixed-wing method (200-m strip
transects) are well known, but it continues to be used because it provides an
index of trends, because there are now long runs of data (almost 20 years in
some cases) collected in this standard form and an alternative method is
lacking. In this study, four variations of fixed-wing surveys of kangaroos
were investigated: two line-transect methods (involving different scanning
techniques), the standard 200-m strip transect and a 100-m strip transect.
Surveys using these methods were compared with helicopter line-transect
surveys along the same flight lines in three areas (5000–7500
km2) in western Queensland. Both fixed-wing
line-transect methods failed to produce consistently accurate estimates of
density for all three species surveyed: red kangaroos
(Macropus rufus), eastern grey kangaroos
(M. giganteus) and common wallaroos
(M. robustus). While generally more accurate than the
uncorrected strip-transect counts, they were no less variable. However, the
strip-transect counts still need to be corrected for bias for which this study
offers revised estimates of correction factors for eastern grey kangaroos
(3.7–10.2) and common wallaroos (3.8–4.1), and estimates for red
kangaroos (1.7–2.7) that support currently used values. An attractive
alternative is to survey in 100-m strip transects, which offer improved
visibility (correction factors of 1.0–1.8 for red kangaroos,
2.1–3.6 for eastern grey kangaroos and 1.7–2.1 for common
wallaroos) and are therefore likely to be more accurate and repeatable.
However, these advantages need to be assessed in relation to continuing long
runs of data using the standard 200-m strip transect. Correction factors for
wallaroos are conservative as helicopter-based density estimates are known to
be underestimates. Further work is needed to assess the generality of
correction factors, both spatially and temporally.
Diet of the mulgara, Dasycercus cristicauda (Marsupialia : Dasyuridae), in the Simpson Desert, central Australia
Authors: Chen Xiaolin , Dickman Chris R. , Thompson Michael B.
Published: August 2004

The diet of the mulgara, Dasycercus cristicauda, from
the Simpson Desert in Queensland, was analysed using scats collected between
1990 and 1995. Insects, arachnids and rodents were the main classes of prey of
D. cristicauda, but reptiles, centipedes and small
marsupials were also consumed. Insects represented 92% by percentage
frequency of occurrence in scats, while rodents represented 33% by
percentage frequency. Invertebrate prey ≥6 mm in length and vertebrate prey
occurred frequently in scats, but small prey ( 1–5 mm), when present,
occurred in large numbers. D. cristicauda ate more
individual prey items in spring and winter than in autumn, and more
large-sized prey in spring than in autumn. In autumn,
D. cristicauda consumed mostly insects (100% by
frequency) and few rodents (8%), but in winter and spring, switched to
rodents (38% and 47% respectively) and insects (88% and
93% respectively). Seasonal shifts in diet may reflect changes in the
availability of different groups of prey, or changes in prey selectivity by
D. cristicauda in response to costs imposed by seasonal
reproduction. The dietary flexibility of D. cristicauda
may allow individuals to occupy stable ranges, and has perhaps also promoted
the persistence of the species in arid areas that have been subjected to
changes in land use since European settlement.
Ecological traits of commercially harvested water monitors, Varanus salvator, in northern Sumatra
Authors: Shine Richard , Ambariyanto  , Harlow Peter S. , Mumpuni
Published: August 2004

An important step towards evaluating ecological sustainability of resource use
is to understand the characteristics of that resource. Indonesian populations
of the Asian water monitor (Varanus salvator) have been
heavily exploited over several decades for the reptile skin industry. We
visited two cities in northern Sumatra (Rantauprapat and Cikampak) to gather
information on the sizes, sexes, reproductive status and food habits of
harvested specimens. Data on 399 lizards showed that monitors in northern
Sumatra are similar in most respects to those studied previously in southern
Sumatra (Palembang), despite the considerable distance between the two areas
and the significant difference in climates. Male water monitors mature at a
smaller size than females, but grow to larger body sizes. Harvesting is
concentrated on adult males, and adult plus juvenile females. Reproduction
occurs year-round, but at a lower intensity in drier months (March and June).
Females produce multiple clutches of 6–17 eggs each year. These lizards
eat a wide variety of prey, including commensal vertebrates (e.g. rats,
chickens) as well as invertebrates (e.g. insects, crabs). The numbers of
stomach parasites (spirurid nematodes, Tanqua tiara)
were higher in juvenile lizards than in adults, and varied between our two
sampling sites. Our results suggest that water monitors exhibit relatively
little morphological or ecological divergence over broad areas within Sumatra,
hence simplifying the task of developing appropriate management systems for
the commercial harvest.
Aerial survey methodology and the cost of control for feral goats in Western Queensland
Authors: Pople A. R. , Clancy T. F. , Thompson J. A. , Boyd-Law S.
Published: August 2004

Feral goats (Capra hircus) were shot from a helicopter
on four sites in central-western Queensland. These sites centred on Idalia
National Park (660 km2) and three nearby properties:
Lissoy (360 km2), Mt Calder (260
km2) and Ravensbourne (320 km2),
the order reflecting increasing goat density. On Idalia, 134 goats were shot
in 8 h of flying time. On Lissoy, 28 goats were shot in 3 h, 1038 goats were
shot on Mt Calder in 15 h, while 2307 goats were shot on Ravensbourne in 21 h.
The reduction was monitored by aerial surveys using fixed-wing aircraft. No
goats were recorded on either Idalia or Lissoy immediately following shooting
and substantial reductions in goat numbers were achieved on Mt Calder
(75%) and Ravensbourne (49%). Surveys conducted six months after
this reduction indicated population increases on all sites following shooting.
This was particularly marked on Ravensbourne, where goat numbers had increased
by 31% despite further substantial removals by commercial mustering.
These population increases were largely the result of immigration. The
cooperation of landowners over a large area is therefore essential for
effective control of goats. The per capita cost of
shooting goats from a helicopter was essentially constant down to a threshold
density of <1 goat km-2 , below which the cost
increased substantially.
The accuracy of fixed-wing aerial surveys was improved by using
double-counting and these corrected estimates compared favourably with
index–manipulation–index estimates. Estimates of densities <1
goat km-2 were imprecise and at these densities goats
were difficult to detect. The extent of vegetation cover did not affect the
sightability of goats, whereas group size was positively correlated with the
sightability of goats. To estimate true density, correction factors of
1–2 were applied to goat group sizes using survey parameters of 100 m
strip width, a survey height of 76 m and a speed of 187 km
h-1.
Accelerated immunosenescence in preindustrial twin mothers
Authors: Helle Samuli , Lummaa Virpi , Jokela Jukka
Published: August 2004

Life-history theory predicts a tradeoff between reproductive effort and lifespan. It has been suggested that this tradeoff is a result of reproductive costs accelerating senescence of the immune system, leading to earlier death. Longevity costs of reproduction are suggested for some human populations, but whether high reproductive effort leads to impaired immune function is unknown. We examined how reproductive effort affected postreproductive survival and the probability of dying of an infectious disease in women born in preindustrial Finland between 1702 and 1859. We found that mothers delivering twins had reduced postreproductive survival after age 65. This effect arose because mothers of twins had a higher probability of succumbing to an infectious disease (mainly tuberculosis) than mothers delivering singletons. The risk among mothers of twins of dying of an infectious disease was further elevated if mothers had started reproducing early. In contrast, neither female postreproductive survival nor the risk of succumbing to an infectious disease was influenced by the total number of offspring produced. Our results provide evidence of a long-term survival cost of twinning in humans and indicate that the mechanism mediating this cost might have been accelerated immunosenescence.
Chemical chaperones protect from effects of apoptosis-inducing mutation in carbonic anhydrase IV identified in retinitis pigmentosa 17
Authors: Bonapace Giuseppe , Waheed Abdul , Shah Gul N. , Sly William S.
Published: August 2004

Carbonic anhydrase (CA) IV is a glycosylphosphotidylinositol-anchored enzyme highly expressed on the plasma face of microcapillaries and especially strongly expressed in the choriocapillaris of the human eye. In collaboration with scientists at the University of Cape Town (Rondebosch, South Africa), we recently showed that the R14W mutation in the signal sequence of CA IV, which they identified in patients with the retinitis pigmentosa (RP) 17 form of autosomal dominant RP, results in accumulation of unfolded protein in the endoplasmic reticulum (ER), leading to ER stress, the unfolded protein response, and apoptosis in a large fraction of transfected COS-7 cells expressing mutant, but not wild-type, CA IV. Here we present experiments showing that several well characterized CA inhibitors largely prevent the adverse effects of expressing R14W CA IV in transfected COS-7 cells. Specifically, CA inhibitors prevent the accelerated turnover of the mutant protein, the up-regulation of Ig-binding protein, double-stranded RNA-regulated protein kinase-like ER kinase, and CCAAT/enhancer-binding protein homologous protein (markers of the unfolded protein response and ER stress), the inhibition of production of other secretory proteins expressed from COS-7-transfecting plasmids, and the induction of apoptosis, all characteristics of transfected cells expressing R14W CA IV. Furthermore, treatment with 4-phenylbutyric acid, a nonspecific chemical chaperone used in other protein-folding disorders, also dramatically reduces the apoptosis-inducing effect of expressing
R14W CA IV
cDNA in transfected COS-7 cells. These experiments suggest a promising approach to treatment of RP17 that might delay the onset or possibly prevent this autosomal dominant form of RP.
A mechanism for slow release of biomagnified cyanobacterial neurotoxins and neurodegenerative disease in Guam
Authors: Murch Susan J. , Cox Paul Alan , Banack Sandra Anne
Published: August 2004

As root symbionts of cycad trees, cyanobacteria of the genus
Nostoc
produce β-methylamino-
l
-alanine (BMAA), a neurotoxic nonprotein amino acid. The biomagnification of BMAA through the Guam ecosystem fits a classic triangle of increasing concentrations of toxic compounds up the food chain. However, because BMAA is polar and nonlipophilic, a mechanism for its biomagnification through increasing trophic levels has been unclear. We report that BMAA occurs not only as a free amino acid in the Guam ecosystem but also can be released from a bound form by acid hydrolysis. After first removing free amino acids from tissue samples of various trophic levels (cyanobacteria, root symbioses, cycad seeds, cycad flour, flying foxes eaten by the Chamorro people, and brain tissues of Chamorros who died from amyotrophic lateral sclerosis/Parkinsonism dementia complex), we then hydrolyzed the remaining fraction and found BMAA concentrations increased 10- to 240-fold. This bound form of BMAA may function as an endogenous neurotoxic reservoir, accumulating and being transported between trophic levels and subsequently being released during digestion and protein metabolism. Within brain tissues, the endogenous neurotoxic reservoir can slowly release free BMAA, thereby causing incipient and recurrent neurological damage over years or even decades, which may explain the observed long latency period for neurological disease onset among the Chamorro people. The presence of BMAA in brain tissues from Canadian patients who died of Alzheimer's disease suggests that exposure to cyanobacterial neurotoxins occurs outside of Guam.
Introduction: Earnings inequalities: gender, race and sexual orientation
Authors: Meulders Danièle , Plasman Robert , Rycx François
Published: August 2004

Introduces a collection of papers originally presented at the 79th Applied Econometrics Association Conference which was organised with the specific aim of stimulating discussion on the “econometrics of wages”. Topics of particular focus include gender wage gaps and wage discrimination. The papers provide insight into the magnitude and sources of gender, racial and sexual orientation earnings inequalities.
Biometric systems
Authors: Rudall B.H.
Published: August 2004

Presents reports and surveys of selective research and development in systems and cybernetics. They include: biometric systems; artificial intelligence; innovations; cybernetics and automation and quantum computing.
Incorporating data mining and computer graphics for modeling of neural networks
Authors: Segall Richard S.
Published: August 2004

Provides a background on the concepts and development of data mining and data warehousing that need to be known by students and educators. Then discusses the applications of data mining for the construction of graphical mappings of the sensory space as a two‐dimensional neural network grid as well as the traveling salesman problem (TSP) and simulated annealing. Data mining is also used as a tool for the construction of computer graphics as solutions to the TSP and also for the activation of an output neuron for a three‐layer feed‐forward network that is trained using a Boolean function. Conclusions and future directions of the research are also discussed.
A change of radix
Authors: Andrew Alex M.
Published: August 2004

The use of ten as a radix for everyday numbering seems to be a suitable compromise. Non‐decimal numbers have applications in error detection and in computing. In the latter, it is interesting that there has been competition between octal and hexadecimal formats for manual interaction, and one reason for the prevalence of the latter is attributed to the use of seven‐line character displays and an improbable feature of this in relation to the English alphabet.
An economic analysis of Ireland's first public private partnership
Authors: Hurst Claire , Reeves Eoin
Published: August 2004

In 1999, the Irish Government launched a programme of public private partnerships (PPPs). The programme has expanded rapidly as policy makers seek to address the country's acute deficit of physical infrastructure. The first PPP to reach the stage of operation is the contract for five secondary schools. The early evidence from this case demonstrates that the market for education projects is competitive. The contract was designed on the basis of securing an appropriate distribution of risk and limiting private sector rents from re‐financing. However, the evidence indicates that this PPP has not resulted in significant innovations and the public sector has failed to provide any evidence of value for money.
The impact of a national policy to enhance teaching quality and status, England, the United Kingdom
Authors: Gosling David
Published: August 2004

The Teaching Quality Enhancement Fund was established by the Higher Education Funding Council for England, UK, with the declared aims of enhancing the quality of teaching and learning and raising the status of teaching among higher education institutions. This paper considers the three strands of the initiative – subject, institutional, and individual – and uses findings from a variety of evaluation studies to assess the impact of this state sponsored policy. The difficulties in creating cultural change within higher education are discussed. The paper argues, with cautious optimism, that there is evidence of increased attention being paid to teaching in higher education in England, in part, as a consequence of this funded initiative, but that the evidence for wholesale cultural change remains difficult to interpret.