bluuebunny/crossref_metadata_2025 huggingface dataset:
Ex situ prepared Si nanocrystals embedded in silica glass: Formation and characterization
Authors: Švrček V. , Slaoui A. , Muller J.-C.
Published: February 2004

In this article we present an alternative approach for the fabrication of silicon nanocrystals (Si–nc) prepared ex situ of the silicon dioxide (SiO2) host matrix. The Si–nc are scratched from porous silicon layers and incorporated into a host spin-on-glass SiO2 based matrix. High-resolution transmission electron microscopy and Raman spectroscopy revealed Si–nc of 2–5 nm size. These nanocrystallites exhibit visible room temperature photoluminescence (PL) with a maximum at about 700 nm. The presence of the dopant in the host matrix is shown to induce a blueshift of the PL maxima due to modified surface states of the Si–nc. This approach allows the fabrication of self-supporting samples with very high Si–nc concentrations. A bright photoluminescence at room temperature is obtained on such materials. Finally, strong indication of optical gain at room temperature is shown for samples with high Si–nc concentrations in a phosphorus doped sol gel host matrix.
Laser-induced cavitation bubbles for cleaning of solid surfaces
Authors: Song W. D. , Hong M. H. , Lukyanchuk B. , Chong T. C.
Published: February 2004

When a high-power laser beam is focused into liquid, it results in a shock wave emission and cavitation bubble generation. Upon inserting a rigid substrate into the liquid, the bubbles migrate towards the substrate due to the Bjerknes attractive force. Due to bubble–substrate and/or bubble–free-surface interaction, a high-speed liquid jet is formed during bubble collapse, and a collapse shock wave is generated at the moment of bubble collapse near the substrate. These shock waves and liquid jet induce large forces acting on the substrate to remove particles from it. For a substrate several millimeters away from the laser focus point, the collapse shock wave and liquid jet play key roles in removal of particles. The cleaning efficiency increases with an increase of laser fluence and decreases with an increase of distance between substrate surface and laser beam focus point or depth below liquid surface. In a case of bubbles close to substrate and liquid-surface boundaries, implosion of the bubbles will give rise to shock waves and liquid jets oblique to the substrate surface with the parallel and perpendicular components of the forces onto the particles. These oblique liquid jets and shock waves result in high cleaning efficiency. A liquid, such as alcohol and commercial washing solution, as the surrounding medium, rather than air or vacuum, can reduce adhesion force and enhance cleaning efficiency.
Permeability dependence of the effective magnetostriction of magnetostrictive composites
Authors: Wan Y. P. , Zhong Z. , Fang D. N.
Published: February 2004

A model is presented in this article to investigate the dependence of effective magnetostriction of the magnetostrictive composites on the parameters of components including the elastic modulus, permeability, and volume fraction, etc. Concentrating on the two-component magnetostrictive composites and choosing the two components to be general magnetostrictive materials, this model yields, analytically, the effective magnetostriction of composites by means of the method of complex potential. In terms of the analysis of this model, the magnetostrictive composites can be roughly divided into two kinds. One kind is that the matrix material is nonmagnetic or a material with very low magnetostriction, in which the effective magnetostriction is independent of the permeability of components. Another kind is the case in which the two components have close magnetostriction, and the effective magnetostriction of the composites generally depends on the elastic and the magnetic parameters of both components and the volume fraction. Unlike the first kind of composite, in a certain range, effective magnetostriction of this kind of composite can be improved by increasing the permeability of matrix. In addition, dependence of the effective magnetostriction on the other parameters of the components has also been discussed systematically. To evaluate the accuracy of this model, comparisons are made between the theoretical values and the experimental results published in the literature, which indicate that predictions of this model agree qualitatively with the experimental data.
Interdiffusion and thermal stability in magnetic tunnel junction ferromagnet/insulator/ferromagnet trilayer structures
Authors: Park Sungkyun , Keavney David J. , Falco Charles M.
Published: February 2004

We used molecular beam epitaxy grown magnetic tunnel junction structures for thermal stability studies using x-ray photoelectron spectroscopy (XPS) and in situ scanning tunneling microscopy (STM). Unannealed trilayers show no oxidation of the bottom magnetic layer for barriers thicker than 1.1 nm. However, upon annealing, we find that the metallic XPS peak of the top layers decrease dramatically, while that of the bottom and barrier layers increases. STM images of the Co top layer on the Al–oxide barrier show that the Co does not agglomerate upon annealing up to 500 °C, which suggests interdiffusion is the most likely explanation for the XPS data.
Analytical fit of the I–V probe characteristic for finite ion temperature values: Justification of the radial model applicability
Authors: Crespo R. Morales , Fernández Palop J. I. , Hernández M. A. , Ballesteros J.
Published: February 2004

This article deals with an extension of the radial model for the sheath that surrounds a cylindrical or spherical Langmuir probe immersed in a plasma in which positive ion thermal motion is taken into account. The dependence of the electric potential profile and of the I–V characteristic on the positive ion temperature is obtained. Moreover, a different parameterization is established from a numerical fit of the I–V characteristic as a function of the probe radius, the biasing potential, and the ratio between the positive ion temperature and the electron temperature. This parameterization allows us to obtain an analytical approximation to the potential profile and the sheath edge. Finally, it also gives us a means of justifying under what conditions the radial model can be applied in plasmas with finite positive ion temperature.
Photoelectron circular dichroism in core level ionization of randomly oriented pure enantiomers of the chiral molecule camphor
Authors: Hergenhahn Uwe , Rennie Emma E. , Kugeler Oliver , Marburger Simon , Lischke Toralf , Powis Ivan , Garcia Gustavo
Published: February 2004

The inner-shell photoionization of unoriented camphor molecules by circularly polarized light has been investigated from threshold to a photoelectron kinetic energy of ∼65 eV. Photoelectron spectra of the carbonyl C 1s orbital, recorded at the magic angle of 54.7° with respect to the light propagation direction, show an asymmetry of up to 6% on change of either the photon helicity or molecular enantiomer. These observations reveal a circular dichroism in the angle resolved emission with an asymmetry between forward and backward scattering (i.e., 0° and 180° to the light beam) which can exceed 12%. Since the initial state is an atomiclike spherically symmetric orbital, this strongly suggests that the asymmetry is caused by final-state effects dependent on the chiral geometry of the molecule. These findings are confirmed by electron multiple scattering calculations of the photoionization dynamics in the electric-dipole approximation.
Coupling in a twin-core microstructured polymer optical fiber
Authors: Padden W. E. P. , van Eijkelenborg M. A. , Argyros A. , Issa N. A.
Published: February 2004

Theoretical calculations and experimental results are reported for a microstructured polymer optical fiber twin-core coupler. Beat lengths are calculated using a fully vectorial, Fourier decomposition method, which show that the beat length is extremely sensitive to any core asymmetry. Reasonably good agreement between theory and experiment is obtained.
Bistable defect in mega-electron-volt proton implanted 4H silicon carbide
Authors: Martin D. M. , Kortegaard Nielsen H. , Lévêque P. , Hallén A. , Alfieri G. , Svensson B. G.
Published: February 2004

Epitaxial 4H-SiC n-type layers implanted at room temperature with a low fluence of mega-electron-volt protons have been measured by deep level transient spectroscopy (DLTS). The proton fluence of 1×1012 cm−2 creates an estimated initial concentration of intrinsic point defects of about 1014 cm−3 of which about 10% remain after the implantation and gives rise to deep states in the upper part of the band gap. Here, we investigate the samples prior to high-temperature annealing and a very complex spectrum is revealed. In particular, a bistable defect M is discovered having two DLTS peaks, M1 and M3 at EC−0.42 and around EC−0.75 eV, respectively, in one configuration and one peak, M2 at EC−0.70 eV in the other configuration. The charge dependent thermal activation energies for the transformation between the bistable defect peaks are 0.90 and 1.40 eV.
Soft electron impact ionization in crossed molecular beam reactive scattering: The dynamics of the O(3P)+C2H2 reaction
Authors: Capozza Giovanni , Segoloni Enrico , Leonori Francesca , Volpi Gian Gualberto , Casavecchia Piergiorgio
Published: February 2004

Soft ionization by low-energy, tunable electrons is implemented for the first time in crossed molecular beam reactive scattering experiments with mass-spectrometric detection. The power of the method, which permits the suppression of the dissociative ionization of interfering species, is exemplified with the study of the O(3P)+C2H2 multichannel reaction.
Sensitivity of Pt/ZnO Schottky diode characteristics to hydrogen
Authors: Kim Suku , Kang B. S. , Ren F. , Ip K. , Heo Y. W. , Norton D. P. , Pearton S. J.
Published: February 2004

Pt/ZnO Schottky diodes show changes in forward current of 0.3 mA at a forward bias of 0.5 V or alternatively a change of 50 mV bias at a fixed forward current of 8 mA when 5 ppm of H2 is introduced into a N2 ambient at 25 °C. The rectifying current–voltage (I–V) characteristic shows a nonreversible collapse to Ohmic behavior when as little as 50 ppm of H2 is present in the N2 ambient. At higher temperatures, the recovery is thermally activated with an activation energy of ∼0.25 eV. This suggests that introduction of hydrogen shallow donors into the ZnO is a contributor to the change in current of the diodes.
Transient phenomenon of longitudinal flexural coupled vibrations in a small rectangular piezoelectric ceramic plate (8 mm×2.16 mm×1 mm)
Authors: Ming Yang , Levesley Martin C. , Walker Peter G. , Watterson Kevin
Published: February 2004

The coupling between two vibration modes is usually fixed when the working frequency is determined. However, in this letter, we report a transient coupled vibration phenomenon occurring between second bending and first longitudinal resonant frequencies in a small rectangular piezoelectric ceramic plate (8 mm×2.16 mm×1 mm). At some frequencies, the transient coupled vibration amplitude may increase to a certain level, and at other frequencies, it decreases its vibration amplitude. These experimental results may be helpful to understand the real essence of piezoelectric phenomenon in piezoelectric ceramics and to find applications for small rectangular piezoelectric ceramic plates.
Atom-resolved scanning tunneling microscopy of (In,Ga)As quantum wires on GaAs(311)A
Authors: Wen H. , Wang Z. M. , Salamo G. J.
Published: February 2004

Generally (In,Ga)As strained growth on GaAs surfaces results in zero-dimensional quantum dots. The formation of one-dimensional quantum wires is demonstrated during (In,Ga)As molecular-beam-epitaxial growth on GaAs(311)A at high temperature. The wires are running along the [−233] direction. Atomically resolved scanning tunneling microscopy images reveal that the wires are triangular-shaped in cross section and the two side bonding facets are {11,5,2}. These results are discussed in terms of a mechanism of strain-driven facet formation.
Formation of air stable carbon-skinned iron nanocrystals from FeC2
Authors: Kosugi Kentaroh , Bushiri M. Junaid , Nishi Nobuyuki
Published: February 2004

Charge neutralization reaction in ionic salt of Fe2+C22− is found to produce carbon-skinned Fe nanocrystals. FeC2 is formed as an intermediate product in the reaction of FeCl2 solved in acetonitrile with CaC2 fine powder and also able to be isolated as black nanocrystals. Heating of FeC2 at temperature higher than 250 °C induces segregation of metallic iron. The segregated carbons grow as graphitic sheets parallel to the growing Fe lattice plane. This direct bonding is due to an accidental matching of the Fe–Fe distance (2.866 Å) with that of the C1–C4 distance (2.842 Å) of the hexagonal rings in graphite. The x-ray diffraction pattern indicates that the particles are composed of α-Fe and graphitic carbon. The thickness of the skin is almost constant as thick as 3.5 nm independent of the body size. The particles with an average size of 30 nm exhibit temperature dependence of the magnetic cohesive force as function of T−0.275.
Torsional spring constant obtained for an atomic force microscope cantilever
Authors: Jeon Sangmin , Braiman Yehuda , Thundat Thomas
Published: February 2004

In this letter, a method to measure the torsional spring constant of a microcantilever is described. The cantilever was twisted laterally without any normal load by inducing the Lorentz force. An electrical current was applied to the cantilever in a magnetic field, and the torsional resonance frequency of the cantilever was obtained. Based on the observation that the torsional resonance frequency is the same as the second resonance peak of the thermally vibrating cantilever, the ratio of deflection spring constant to torsional spring constant is easily obtained from a simple relationship. For the cantilever used here, the torsional spring constant is 11.24 N/m, 28 times greater than the deflection spring constant.
On the criteria for the formation of nanoquasicrystalline phase
Authors: Murty B. S. , Hono K.
Published: February 2004

The formation of nanoquasicrystalline phase is reported directly from the liquid on melt spinning over a wide range of wheel velocities of 10–30 m/s in Zr–Pd system at the eutectic composition (Zr75Pd25 alloy). The earlier studies in the Zr–Pd system (Zr70Pd30 and Zr65Pd35 alloys) showed nanoquasicrystallization on annealing of the amorphous phase obtained by melt spinning. Based on the existing results in various systems, a large negative enthalpy of mixing and/or existence of Frank–Kasper-type phases appear to be the crucial criteria for the formation of nanoquasicrystalline phase in any system.
Scanning resistive probe microscopy: Imaging ferroelectric domains
Authors: Park Hongsik , Jung Juhwan , Min Dong-Ki , Kim Sungdong , Hong Seungbum , Shin Hyunjung
Published: February 2004

We report a resistive probe that detects electric field by field-induced resistance changes in a small resistive region at the apex of the tip and demonstrate a method of imaging ferroelectric domains at high speed, which is named scanning resistive probe microscopy (SRPM). We designed and fabricated the probe by self-aligning process that readily implemented the resistive region at the tip apex. In order to measure the field sensitivity, we contacted the probe with a thermally oxidized silicon sample and detected a 0.3% resistance change per volt applied to the sample. We obtained domain images of freshly cleaved triglycine sulfate (TGS) single crystal by contact mode SRPM. The operating voltage of the probe was 4 V and the scan rate and size were 2 Hz and 40×40 μm2, respectively. We controlled the polarization of Pb(Zr0.4Ti0.6)O3 (PZT) by applying voltage between the resistive tip and the bottom electrode of PZT, and acquired the domain images with the same tip at 2 Hz scan rate. By controlling and detecting the ferroelectric domains without an additional signal modulating system, we verified that the resistive probe could detect the ferroelectric domain at high speed and be used as a read/write head of a probe data storage system.
Fluorene-based low band-gap copolymers for high performance photovoltaic devices
Authors: Zhou Qingmei , Hou Qiong , Zheng Liping , Deng Xianyu , Yu Gang , Cao Yong
Published: February 2004

Low band-gap, soluble conjugated copolymers were synthesized from 9,9-dioctylfluorene and 4,7-di-2-thienyl-2,1,3-benzothiadiazole (PFO-DBT) and different composition ratios were used for the donor material in bulk heterojunction polymer photovoltaic cells (PVCs). In PVCs made with PFO-DBT:PCBM (methano-fullerene [6,6]-phenyl C61-butyric acid methyl ester) blends, the spectral response is extended up to 650 nm and the open-circuit voltage (Voc) is improved to 0.95 V. The energy conversion efficiency (ηe) in devices with optimized composition reaches 2.24% under an AM1.5 solar simulator (78.2 mW/cm2). In contrast to organic PVCs previously published, these PVCs retain high energy conversion efficiency at illumination up to 5 suns of AM1.5 spectral illumination. This feature allows high efficiency polymer PVC modules made in combination with a light concentrator.
Periodically poled near-stoichiometric lithium tantalate for optical parametric oscillation
Authors: Yu Nan Ei , Kurimura Sunao , Nomura Yoshiyuki , Nakamura Masaru , Kitamura Kenji , Sakuma Jun , Otani Yoshio , Shiratori Akira
Published: February 2004

A 35-mm-long periodically poled device was fabricated from a near-stoichiometric lithium tantalate, and optical parametric oscillation was demonstrated with a low oscillation threshold (106 mW). The emitted signal and idler wavelengths were 1.53–1.63 and 3.06–3.49 μm, respectively, and the highest slope conversion efficiency was 65% with a maximum output power of 628 mW at 1.1 W pumping. The influence of Curie temperature inhomogeneity on fabrication of the device was investigated to improve poling quality in long devices.
EL2-related metastable defects in semi-insulating GaAs
Authors: Kabiraj D. , Ghosh Subhasis
Published: February 2004

Thermally stimulated current spectroscopy, photoquenching, and photorecovery have been used to reveal the EL2-related metastable defect levels in semi-insulating GaAs. It has been found that one set of metastable levels is directly related to EL2 and the other set is indirectly related to EL2 defect through charge transfer. The origin of these EL2-related metastable levels has been discussed in the context of recently proposed three-center-complex model of EL2 in semi-insulating GaAs.
On the modeling of lattice thermal conductivity in semiconductor quantum dot superlattices
Authors: Khitun Alexander , Liu Jianlin , Wang Kang L.
Published: February 2004

We present a theoretical model for the cross-plane lattice thermal conductivity calculations in semiconductor quantum dot superlattices. Based on continuum approximation, our model takes into account scattering of acoustic phonons on quantum dots. In most practical cases, the dot volume fraction is relatively small and/or dot and host materials have a small acoustic mismatch. This fact lets us take into account only first order scattering events and to significantly simplify the calculations. The results of numerical simulations carried out for Si/Ge quantum dot superlattices show good agreement with experimental data. The proposed model is useful for many applications recently suggested for semiconductor quantum-dot superlattices.
Surface depletion in doped SrTiO3 thin films
Authors: Ohtomo A. , Hwang H. Y.
Published: February 2004

Strong effects of surface depletion have been observed in metallic La-doped SrTiO3 thin films grown on SrTiO3 substrates by pulsed-laser deposition. The depletion layer grows with decreasing temperature due to the large temperature-dependent dielectric response of SrTiO3. When the depletion layer becomes comparable to or exceeds the thickness of the doped film, the Hall mobility shows significant enhancements as more of the electron distribution extends into the undoped substrate, in conceptual analogy to modulation doping in compound semiconductor heterostructures.
Effects of different sowing times on leaf scald and yield components of spring barley under dryland conditions
Authors: Kavak Hamit
Published: February 2004

The effect of sowing date on severity of scald and yield components of barley was studied over 2 years, using 15-day intervals between sowing dates under dryland conditions in Turkey. Disease severity was greatest at the first sowing time, and it decreased linearly at subsequent sowing times in both years. Disease did not develop on flag and second leaves for the third sowing date, and was not observed on any leaf after the fourth and fifth dates of sowing in 2000 and 2001, respectively. After the third sowing date, a decrease in total grain yield and yield components, number of ears per plant, grains per head, and plant height was observed in both infected and control plots. Yield was also reduced by scald and resulted in total grain yield reductions of 10.1% and 6.0% for the first and second sowing dates in 2000, and 16.2%, 9.2%, and 3.0% on the first 3 sowing dates in 2001, respectively. At the first 2 sowing dates only ears per plant was decreased by scald, with respective reductions of 8.3% and 4.4% in 2000, and 14.3% and 8.5% in 2001, when compared with the control plots.
Influence of ad libitum feeding of urea-treated wheat straw with or without corn steep liquor on intake, in situ digestion kinetics, nitrogen metabolism, and nutrient digestion in Nili-Ravi buffalo bulls
Authors: Mahr-un-Nisa  , Sarwar M. , Khan M. Ajmal
Published: February 2004

Influence of different levels of corn steep liquor (CSL) on chemical composition of urea-treated wheat straw (UTWS), feed intake, ruminal characteristics, digestion kinetics, nitrogen (N) metabolism, and nutrient digestibility by ruminally cannulated buffalo bulls was studied using 4 × 4 Latin square design. Wheat straw was treated with 5% urea and ensiled with 0, 3, 6, and 9% CSL on a dry matter (DM) basis and was ensiled in laboratory silos for 5, 10, and 15 days. Neutral detergent fibre (NDF) contents of UTWS ensiled with 0, 3, 6, and 9% CSL were 74.01, 76.16, 77.34, and 78.93%, respectively. Acid detergent fibre (ADF), cellulose, and lignin were similar across treatments. The increase in NDF content was due to increased neutral detergent insoluble nitrogen (NDIN), as when NDF was calculated on crude protein (CP)-free basis (NDF – NDIN × 6.25), its concentration was same for UTWS ensiled with or without CSL. Four diets were formulated to contain 20% concentrate and 80% UTWS ensiled with or without CSL. Dry matter, digestible DM, organic matter (OM), CP, ADF, and NDF intakes were higher in bulls fed UTWS ensiled with CSL. Significant increases in both DM disappearance and rate of disappearance and a reduction in lag time of UTWS ensiled with CSL was noticed. There were significant differences in ruminal ammonia concentrations between diets containing UTWS ensiled with or without CSL at 3, 6, and 12 h postprandial. Higher digestibilities for DM, OM, CP, ADF, and NDF were noted with UTWS ensiled with CSL. Nitrogen balance was positive for all animals; however, the animals fed UTWS ensiled with CSL retained higher amount of N. These results indicated that CSL was very effective in enhancing the utilisation of ammoniated straw for buffaloes by minimising the nutrient loss at ruminal and cellular levels.
Fingerprinting of cauliflower cultivars using RAPD markers
Authors: Astarini Ida A. , Plummer Julie A. , Lancaster Rachel A. , Yan Guijun
Published: February 2004

Randomly amplified polymorphic DNA (RAPD) was used to investigate genetic relationships among 25 cultivars of cauliflower (Brassica oleracea var. botrytis L.). Forty decamer primers were examined, among which 15 primers produced polymorphism. Twenty-five polymorphic bands were observed, ranging in size from 428 to 1646 bp. A fingerprinting key was generated using these polymorphic bands. A dendogram was constructed using neighbour-joining analysis based on phylogenetic analysis using parsimony (PAUP). Results indicate that RAPD markers can be used for the routine identification of cauliflower cultivars within B. oleracea var. botrytis L.
A methodology for analysis of sugarcane productivity trends. 2. Comparing variety trials with commercial productivity
Authors: Ellis R. N. , Basford K. E. , Leslie J. K. , Hogarth D. M. , Cooper M.
Published: February 2004

Previous research has reported both agreements and serious anomalies in relationships between production attributes of sugarcane varieties in variety trials (VTs) and commercial production (CP). This paper examines VT and CP data for tonnes of cane per hectare (TCH) and sugar content (CCS). Data, analysed by REML, included 107 VTs and 54 CP mill years for 9 varieties from the mill districts of Mulgrave, Babinda, and Tully for harvest years 1982–99. Important consistencies included high TCH of Q152, high CCS of Q117 and Q120, and low CCS of H56-752. Significant anomalies existed with respect to TCH for Q113, Q117, Q120, Q122, Q138, and H56-752 and to CCS for Q113 and Q124. Investigation of these anomalies was assisted by access to independent REML analyses of CP data for 65 692 individual Tully cane blocks from 1988 to 1999 and by the knowledge of persons familiar with the preferential uses of varieties by farmers. Minor anomalies were due to limited year or mill area data. Q124 TCH was deemed to be decreased and its CCS increased by severe disease in Babinda CP in the extremely wet 1998 and 1999 seasons. Other serious anomalies have credible but unsubstantiated explanations. The most convincing, for Q113, Q117, Q138, and H56-752, are that these varieties were deployed unevenly with regard to late season harvesting, predominant use or avoidance on high fertility soils, or use confined to low fertility sandy soils, respectively. Uneven deployment results in confounding of these effects in the varietal CP statistics at mill area level. It is concluded that VTs cannot be enhanced to anticipate or evaluate most effects of uneven deployment. They give adequate predictions of relative CP performance for varieties deployed evenly across confounding influences. Routine analyses of individual block CP data would be useful and enhanced by addition of relevant information to the block records.
Effect of liquid to feed ratio, steeping time, and enzyme supplementation on the performance of weaner pigs
Authors: Choct M. , Selby E. A. D. , Cadogan D. J. , Campbell R. G.
Published: February 2004

Two experiments were conducted to examine the effect of liquid to feed ratio, steeping time, and enzyme supplementation on performance of weaner pigs. In Expt 1, 40 male weaner pigs (weaned at 27 days of age) were randomly allocated to 4 treatments, including a dry control and 3 liquid diets of differing liquid: feed ratios (2 : 1, 3 : 1, and 4 : 1). Pigs were fed individually. Bodyweight was measured weekly and feed intake measured daily. The results confirmed the advantage of liquid feeding but indicated that liquid: feed ratio had very little effect on performance of weaner pigs. Whereas the digestible energy (DE) content of the 2 : 1 and 3 : 1 diets was similar to the control diet, the DE content of the 4 : 1 diet was significantly lower, possibly due to the removal of the insoluble marker (long chain hydrocarbon) by the amount of water in the diet.In Expt 2, the effect of a xylanase and steeping time on pig performance was assessed in a 2 × 2 factorial design (2 steeping times, 1 h v. 15 h; enzyme addition, + v. –). Sixty male weaner pigs (weaned at 27 days of age) were randomly allocated to 4 treatments and fed individually for 3 weeks. Bodyweight was measured weekly and feed intake measured daily. The experiment revealed that both steeping and enzyme addition increased feed intake (P�<�0.01) and growth rate (P < 0.05), suggesting that both techniques influence the non-starch polysaccharide composition of the wheat-based diet. Feed conversion ratio (FCR) tended to be improved more by steeping than by enzyme addition (P = 0.06). The results would suggest that steeping improves FCR by allowing increased hydration of feed and subsequent activation of the endogenous enzymes present naturally in grains.The present study was designed to test the hypothesis that the water: solid feed ratio would affect nutrient availability to weaner pigs fed liquid diets.
Effects of season and of manipulation of circulating prolactin concentrations on deiodinase activity in cashmere goat skin
Authors: Rhind S. M. , Kyle C. E. , Duff E. I.
Published: February 2004

The effects of season and of manipulations of circulating prolactin concentrations on the expression of monodeiodinase type II (MDII) and monodeiodinase type III (MDIII) expression in the skin of cashmere goats were investigated. Deiodinase enzymes control the rates of synthesis and degradation of triiodothyronine (T3), a hormone implicated in the control of hair follicle activity, and so changes in expression with season or prolactin profiles may affect cashmere fibre growth and moult. There was a very high degree of variation between animals in expression of each enzyme. There was also evidence of seasonal variation in expression within individuals, with a trend towards lower levels of activity of MDII during periods of long daylength (July and April) and highest levels in December, whereas levels of MDIII were highest in July and lowest in December. Collectively, these differences with season resulted in significant changes with date in the MDIII/MDII ratio. It is concluded that the seasonal changes in deiodinase activity, and in particular in the MDIII/MDII ratio, may have an important role in the regulation of follicle activity. Levels of MD activity were poorly correlated with circulating hormone profiles. Nevertheless, since manipulation of the circulating concentrations of prolactin induced additional changes in MDIII/MDII ratios, which were associated with treatment differences in follicle activity or moult, it is concluded that seasonal changes in prolactin may determine patterns of enzyme activity, with high concentrations of prolactin being associated with reduced net levels of T3 synthesis.
Production and evaluation of transgenic sugarcane containing a Fiji disease virus (FDV) genome segment S9-derived synthetic resistance gene
Authors: McQualter R. B. , Dale J. L. , Harding R. M. , McMahon J. A. , Smith G. R.
Published: February 2004

A transgenic line of the sugarcane cultivar Q124 with significantly enhanced resistance to Fiji disease was produced by microprojectile-mediated transformation with a transgene encoding a translatable version of Fiji disease virus (FDV) segment 9 ORF 1 under the control of the maize polyubiquitin promoter. Sixty-four transgenic lines were tested in glasshouse trials by caging the plants with viruliferous Perkinsiella saccharicida planthoppers. After 2 weeks, the planthoppers were removed and the plants monitored for symptoms. One transgenic line showed significantly enhanced resistance to Fiji disease compared with the Q124 parent and other lines showed varying levels of resistance. The molecular phenotypes of the transgenic plants at both the DNA and RNA levels were not entirely consistent with a resistance mechanism based on post-transcriptional gene silencing but were consistent with reports from other sugarcane-virus resistance systems. This is the first report of transgenic sugarcane containing an FDV-derived synthetic resistance gene showing resistance to FDV, although the mechanism of resistance has not yet been elucidated.
Deploying partially resistant genotypes and plastic mulch on the soil surface to suppress spread of lettuce big-vein disease in lettuce
Authors: Latham L. J. , Jones R. A .C.
Published: February 2004

In 5 field experiments on land infested with lettuce big-vein disease (LBVD) at different locations, the incidence of LBVD in partially resistant lettuce breeding line LE169 was always diminished significantly compared with its incidences in susceptible crisphead lettuce genotypes. Also, the fresh weight yield of LE169 was always significantly greater than those of more susceptible genotypes. When different genotypes were grown on virgin land where infested introduced lettuce seedlings were the only source of the disease, LBVD incidence was again significantly diminished and yield significantly greater with LE169. When black plastic mulch was spread on the surface of LBVD-infested soil and LE169 was deployed along with more susceptible lettuce genotypes, presence of mulch and partial resistance both diminished LBVD incidence significantly on their own, but combining the two suppressed spread the most. The mulch diminished soil moisture and increased soil temperature, one or both of which decreased activity of the viruliferous zoospores of its Olpidium brassicae vector, resulting in less virus transmission to lettuce roots.
Current and potential uses of optical remote sensing in rice-based irrigation systems: a review
Authors: Niel T. G. Van , McVicar T. R.
Published: February 2004

For high water usage cropping systems such as irrigated rice, the positive outcomes of producing a staple food source and sustaining the economy often come at the cost of high resource use and environmental degradation. Advances in geospatial technology will play an increasingly important role in raising productivity and resource use efficiency and reducing environmental degradation, both worldwide and within Australia. This paper reviews the current use of one of these technologies, remote sensing, with the rice-growing region in Australia as a case study. Specifically, we review applications of remote sensing in crop identification, area measurement, regional yield forecasting, and on-farm productivity monitoring and management. Within this context, consideration is given to classification algorithms and accuracy assessment, hyperspectral remote sensing, positional and areal accuracy, linear mixture modelling, methane (CH4) emissions, yield forecasting techniques, and precision agriculture. We also discuss the potential for using remote sensing to assess crop water use, which has received little attention in rice-based irrigation systems, even though it is becoming increasingly important in land and water management planning for irrigation areas. Accordingly, special attention is given to the role of remote sensing with respect to the surface energy balance, the relationship between surface temperature and remotely sensed vegetation indices, and water use efficiency. A general discussion of other geospatial issues, namely geographic information systems and spatial interpolation, is provided because earth-science analysis using remote sensing is often intrinsically integrated with other spatially based technologies and aspects of geographical science.
Estimates of the complete genetic covariance matrix for traits in multi-trait genetic evaluation of Australian Hereford cattle
Authors: Meyer Karin , Johnston David J. , Graser Hans-Ulrich
Published: February 2004

Estimates of covariance components among all 22 traits considered in the current multi-trait genetic evaluation of Australian Hereford cattle were obtained. Traits included 5 weight traits, 8 traits measured through live ultrasound scanning, 3 traits related to reproductive performance, and 6 carcass traits. Estimates were obtained by restricted maximum likelihood, carrying out a series of bivariate analyses. Data for each analysis were selected attempting to maximise the number of animals or animal–parent pairs that had both traits recorded. Estimates were pooled using a weighted 'iterative summing of expanded part matrices' procedure, which ensured positive semi-definite covariance matrices. Models of analyses for individual traits closely resembled those used in genetic evaluation. Results generally agreed with literature results, although estimates of genetic parameters for carcass traits that had few records available tended to fluctuate. Except for 'days to calving', heritability estimates were moderate to high for all traits. Genetic parameters for early growth were different to those for other breeds, with maternal effects for weaning weight being considerably more important and the heritability somewhat lower.
Factors supporting the non-persistence of fruit fly populations in South Australia
Authors: Maelzer D. A. , Bailey P. T. , Perepelicia N.
Published: February 2004

For purposes of interstate and international fruit trade, it is necessary to demonstrate that in areas in which fruit fly species have not previously established permanent populations, but which are subject to introductions of fruit flies from outside the area, the introduced population once detected, has not become established. In this paper, we apply methodology suggested mainly by Carey (1991, 1995) to introductions of Mediterranean fruit fly (Medfly), Ceratitis capitata Weid., and Queensland fruit fly (QFF) Bactrocera tryoni Froggatt (Diptera: Tephritidae) to South Australia, a state in which these species do not occur naturally and in which introductions, once detected, are actively treated. By analysing historical data associated with fruit fly outbreaks in South Australia, we demonstrate that: (i) fruit flies occur seasonally, as would occur in established populations, except there is no evidence of the critical spring generation of either species; (ii) there is no evidence of increasing frequency of outbreaks, trapped flies or larval occurrences over 29 years; (iii) there is no evidence of decreasing time between catches of adult flies as the years progress; (iv) there is no decrease in the mean number of years between outbreaks in the same locations; (v) there is no statistically significant recurrence of outbreaks in the same locations in successive years; (vi) there is no evidence of spread of outbreaks outwards from a central location; (vii) the likelihood of outbreaks in a city or town is related to the size of the human population; (viii) introduction pathways by road from Western Australia (for Medfly) and eastern Australia (for QFF) are shown to exist and to illegally or accidentally carry considerable amounts of fruit into South Australia; and (ix) there was no association between the numbers of either Queensland fruit fly or Medfly and the spatial pattern of either loquat or cumquat trees as sources of larval food in spring. This analysis supports the hypothesis that most fruit fly outbreaks in South Australia have been the result of separate introductions of infested fruit by vehicular traffic and that most of the resultant fly outbreaks were detected and died out within a few weeks of the application of eradication procedures. An alternative hypothesis, that populations of fruit flies are established in South Australia at below detectable levels, is impossible to disprove with conventional technology, but the likelihood of it being true is minimised by our analysis. Both hypotheses could be tested soon with newly developed genetic techniques.
Assessing barley (Hordeum vulgare) response to clipping in the semi-arid Mediterranean climate
Authors: El-Shatnawi M. K. J. , Haddad N. I.
Published: February 2004

Greenhouse pot trials and field experiments were carried out under rain-fed condition in north-eastern Jordan during 1997–98 and 1998–99 growing seasons, to test 3 barley genotypes for their suitability for both forage and grain production. The varieties Rehani and ACSAD176 produced higher forage yields than Rum. In the field, clipping reduced subsequent grain yield per plant by about 18%, lowering grain weight of the main spike from 2.3�g in the control to 1.8 g in the clipped plants. Clipping increased tiller density of barley plants in the field. Decreases in grain yield following clipping could also be attributed to reductions in the number of grains per spike. Clipping decreased the number of grains per spike by about 9% by reducing the number of spikelets per spike. Cutting reduced 1000-grain weight by about 9%. Clipping induced changes in the relative importance of yield components influencing subsequent grain yield. The yield components reduced by clipping were the most important contributors to loss of grain yield.
Effect of Klebsiella pneumoniae and Azospirillum halopraeferens on the growth and development of two Salicornia bigelovii genotypes
Authors: Rueda-Puente E. O. , Castellanos T. , Troyo-Diéguez E. , León-Alvarez J. L. Díaz de
Published: February 2004

Growth and development of 2 pickleweed (Salicornia bigelovii Torr.) genotypes, a local wild type and cultivar, SOS-10, were studied under field conditions. When inoculated with the previously selected and cultivated native strains of Klebsiella pneumoniae and Azospirillum halopraeferens, the 2 pickleweed genotypes exhibited increases in some of the growth and development parameters measured, such as weight, plant length and biochemical characteristics, including total protein, ash and total lipid content in selected plant parts. Our findings suggest that yields of both genotypes of S. bigelovii, under field conditions, can be enhanced by the application of K. pneumoniae or A. halopraeferens strains. The potential usefulness of S. bigelovii for agricultural producers in coastal semi-arid zones has been shown elsewhere; our findings suggest that the establishment and growth of this halophyte can be experimentally improved using beneficial bacteria as auxiliary biofertilisers.
Development of DNA fingerprinting keys for the identification of radish cultivars
Authors: Pradhan A. , Yan G. , Plummer J. A.
Published: February 2004

Identification of cultivars is extremely important both for cultivation and breeding of crop plants. Cultivar identification based on morphological characteristics can be difficult and complicated. Polymerase chain reaction technologies, such as random amplified polymorphic DNA (RAPD) analysis, can readily and quickly identify cultivars using seeds and young leaves. Sixty individuals representing 7 radish cultivars were examined for RAPD marker polymorphism. Based on the polymorphism generated, 5 primers were selected, out of the 14��examined, to fingerprint the cultivars. The 5 primers produced a total of 52 fragments, 6 monomorphic and 46�polymorphic fragments, ranging in size from 206 to 2258 base pairs. A total and mean character difference matrix was calculated based on the RAPD data and a dendrogram was constructed using the unweighted pair-group method with arithmetic averages (UPGMA). Three DNA fingerprinting keys were developed for the 7 cultivars and 5 markers derived from 3 primers was the minimum required to distinguish cultivars. Results demonstrated that RAPD markers could be effectively used for the identification of radish cultivars.
Yield losses caused by virus infection in four combinations of non-persistently aphid-transmitted virus and cool-season crop legume
Authors: Latham L. J. , Jones R. A. C. , Coutts B. A.
Published: February 2004

Field experiments provided quantitative information on the yield losses caused by virus infection within 4 different combinations of non-persistently aphid-transmitted virus and cool-season crop legume: Alfalfa mosaic virus (AMV) in chickpea, faba bean and lentil, and Cucumber mosaic virus (CMV) in lentil. Virus infection foci were introduced into plots and naturally occurring aphids spread infection from these to the other plants. Plants were tagged individually when typical virus symptoms first appeared during the growing period. Paired plant comparisons between symptomatic and asymptomatic plants were made to measure different yield loss parameters. Late infection with AMV in faba bean cv. Fiord diminished shoot dry weight by 41% and seed yield by 45%, but plants infected earlier recovered sufficiently from their initial shock reaction not to produce significant yield losses. In plants of lentil cv. Matilda first showing symptoms at different times, infection with AMV decreased shoot dry weight by 74–76%, seed yield by 81–87% and individual seed weight by 10–21%, while CMV diminished shoot dry weight by 72–81%, seed yield by 80–90% and individual seed yield by 17–25%. Early infection with AMV killed plants of chickpea cv. Tyson while later infection decreased shoot dry weight by 50%, seed yield by 98% and individual seed weight by 90%. The first tentative evidence for seed transmission of AMV in faba bean is reported with a transmission rate of 0.04%.
Impact of tillage on lupin growth and the incidence of pathogenic fungi in southern New South Wales
Authors: Simpfendorfer S. , Heenan D. P. , Kirkegaard J. A. , Lindbeck K. D. , Murray G. M.
Published: February 2004

Narrow-leafed lupins (Lupinus angustifolius) were grown in cultivated and direct-drilled plots at 4 field sites in southern New South Wales in 1998 to determine the effect of tillage on seedling vigour, disease and yield. The early growth of lupins in direct-drilled plots was reduced compared with seedlings in cultivated plots at 3 of the sites. However, the biomass of lupin plants in the direct-drilled treatments was 20% greater than in adjacent cultivated plots at harvest. The lower biomass in cultivated plots appeared to be primarily related to an increased incidence and severity of stem rot caused by Sclerotinia sclerotiorum. The increased stem rot in cultivated plots was also associated with a decline in yield of between 16 and 35% across the sites compared with direct-drilled plots. The direct-drilled treatment reduced the severity of brown spot, caused by Pleiochaeta setosa, at the 2 sites where stubble was retained from the previous wheat crop. These results suggest that direct drilling into cereal residue provides benefits over cultivation for the growth of lupins in southern New South Wales where crop infection by Sclerotinia and/or brown spot may be significant.
Camelostrongylus mentulatus in domestic goats from the Iberian Peninsula
Authors: Ruiz de Ybáñez M.R. , Garijo M.M. , Carpintero M. , Martínez-Carrasco C. , Ortiz J.M.
Published: February 2004

Two male worms of Camelostrongylus mentulatus were found in one of 84 murciano-granadina goats in Murcia, south-eastern Spain. This is the first report of C. mentulatus in goats in the Iberian peninsula and the possible origin and transmission of this nematode in Spain are discussed.
The origin of the triploid in Paragonimus westermani on the basis of variable regions in the mitochondrial DNA
Authors: Agatsuma T. , Iwagami M. , Sato Y. , Iwashita J. , Hong S.J. , Kang S.Y. , Ho L.Y. , Su K.E. , Kawashima K. , Abe T.
Published: February 2004

Triploid, parthenogenetic forms of the lungfluke, Paragonimus westermani, occur in Japan, Korea and China. The origin(s) of triploidy has been debated over the years. Sequences of two regions in the mitochondrial DNA, i.e. partial lrRNA (16S), and a portion of the non-coding region, were obtained from natural populations of P. westermani. All triploid individuals (Japan, Korea, China) and a single tetraploid individual (China) had identical sequences in the 16S region studied. Some sequence variation was observed among diploids, with those from Taiwan being distinct from the remainder. Both neighbour joining and parsimony trees using the 16S region placed diploid individuals from southwestern Japan close to the triploids and the tetraploid. The fragment amplified from the mitochondrial non-coding region showed dimorphism. One form (type A) consisted of 239bp comprising two identical tracts of 70bp separated by a tract of 93bp. The second form (Type B) consisted of only a single 70bp tract. All diploid individuals from Taiwan, China and Korea possessed type A, while those from Japan were polymorphic; individuals from Oita and Hyogo had type B, those from Chiba had type A, but both types were found in Mie. On the other hand, all of the triploid individuals and two tetraploid individuals possessed type B. Both the form present in the non-coding region and the 16S sequence suggest an affinity between a south-eastern group of diploid populations in Japan and the triploid form. A possible mechanism responsible for the origin of the triploid is discussed.