bluuebunny/crossref_metadata_2025 huggingface dataset:
Lingual Nerve Injury
Authors: Graff‐Radford Steven B. , Evans Randolph W.
Published: September 2003

Lingual nerve injury is a common complication following dental and medical procedures. The clinical presentation of lingual nerve injury, its epidemiology, predisposing factors, and anatomy are explored in an attempt to identify those patients at risk for developing neuropathic pain. Nonsurgical and surgical therapies also are discussed.
Efficacy of Eletriptan in Migraineurs With Persistent Poor Response to Nonsteroidal Anti‐inflammatory Drugs
Authors: Chia Yook‐Chin , Lim Shih‐Hui , Wang Shuu‐Jiun , Cheong Y. M. , Denaro Jean , Hettiarachchi Jayasena
Published: September 2003

Background/Objective.—Nonsteroidal anti‐inflammatory drugs continue to be one of the most widely used therapies for migraine, but their efficacy in treating moderate to severe migraine headache has not been well documented. In contrast, the efficacy of triptans in this group of patients is well documented, although no systematic research is available that evaluates the effectiveness of switching to a triptan in patients who respond poorly to nonsteroidal anti‐inflammatory drugs.

Methods.—One hundred thirteen patients who met International Headache Society criteria for migraine and who did not experience satisfactory response to nonsteroidal anti‐inflammatory drugs, received open‐label treatment with a 40‐mg dose of eletriptan for one migraine attack. Efficacy assessments were made at 1, 2, 4, and 24 hours postdose and consisted of headache and pain‐free response rates, absence of associated symptoms, and functional response. Global ratings of treatment effectiveness and preference were obtained at 24 hours.

Results.—The pain‐free response rate at 2 hours postdose was 25% and at 4 hours postdose, 55%; the headache response rate at 2 hours was 66% and at 4 hours, 87%. At 2 hours postdose, relief of baseline associated symptoms was achieved by 41% of patients with nausea compared to 82% of patients at 4 hours; for patients with phonophobia, 67% were relieved at 2 hours and 93% at 4 hours, and for patients with photophobia, 70% were relieved at 2 hours and 91% at 4 hours. Functional response was achieved by 70% of patients by 2 hours postdose. The high level of acute response was maintained over 24 hours, with only 24% of patients experiencing a headache recurrence and only 10% using rescue medication. At 24 hours postdose, 74% of patients rated eletriptan as preferable to any previous treatment for migraine. The most frequent reasons cited for this treatment preference were faster headache improvement (83%) and functional response (78%). Overall, eletriptan was well tolerated; most adverse events were transient and mild to moderate in severity. No serious adverse events were reported.

Conclusion.—Results of this open‐label trial found the 40‐mg dose of eletriptan to have a high degree of efficacy and tolerability among patients who responded poorly to nonsteroidal anti‐inflammatory drugs.
Managing Intractable Migraine With Naratriptan
Authors: Gallagher R. Michael , Mueller Loretta
Published: September 2003

Background.—Intractable migraine presents a significant treatment challenge to both patient and physician. Most attacks are treatable or self‐limiting, but occasionally they may continue for extended periods regardless of treatment.

Objective.—To determine the efficacy of naratriptan 2.5 mg twice daily for the treatment of intractable migraine.

Methods.—We reviewed 24 patients treated with naratriptan twice daily for an intractable migraine attack. Patients were permitted to take prophylactic medication if such treatment had been effective in the past.

Results.—Nineteen patients (79%) improved. Twelve patients showed excellent response with cessation of pain and associated symptoms, 7 patients partially responded with lessening of pain and cessation of associated symptoms, and 5 patients were nonresponsive.

Conclusion.—Short‐term daily administration of naratriptan may be effective in terminating status migrainosus.
Activation of Pain by Sumatriptan
Authors: Coulter David M. , Passier J. L. M. (Anneke) , Clark David W. J. , Van Puijenbroek Eugene P.
Published: September 2003

Objective.—To demonstrate that sumatriptan may induce activation or aggravation of pain at sites of inflammation caused by trauma or disease.

Methods.—Case reports from the national pharmacovigilance centers of 2 countries, The Netherlands and New Zealand, are presented. These reports come from programs that use 2 methodologies to monitor drugs for adverse reactions: spontaneous reporting and a prospective observational cohort study. The potential mechanisms for pain production by sumatriptan are discussed in detail.

Results.—Thirteen case reports of activation of pain by sumatriptan following injury and 8 associated with inflammatory diseases are presented. Most patients had one or more positive rechallenges. This type of reaction occurred at a higher rate with the subcutaneous formulation than with the oral preparation. Pain mostly was severe but short‐lasting; pain was prolonged in some patients with inflammatory disease.

Conclusions.—A strong association has been demonstrated between the use of sumatriptan and the production of pain at sites of inflammation, and there is a plausible pharmacological mechanism for this reaction. Pain activation may be a class effect of the selective serotonergic agonists used in the treatment of migraine.
Treating Chronic Tension‐type Headache Not Responding to Amitriptyline Hydrochloride With Paroxetine Hydrochloride: A Pilot Evaluation
Authors: Holroyd Kenneth A. , Labus Jennifer S. , O'Donnell Francis J. , Cordingley Gary E.
Published: September 2003

Context.—In some individuals, chronic tension‐type headache fails to respond to tricyclic antidepressant medications that often serve as first‐line therapy.

Objective.—To evaluate the clinical efficacy of paroxetine hydrochloride for chronic tension‐type headache not responding to amitriptyline hydrochloride.

Design and Setting.—Open‐label trial of paroxetine conducted at 2 outpatient sites in Ohio.

Participants and Intervention.—Thirty‐one adults (mean age, 37 years; 20 women) with chronic tension‐type headache (mean, 25 headache days per month) who had failed to respond (less than 30% improvement) to treatment with either amitriptyline (n = 13) or matched placebo (n = 18). All participants were treated with paroxetine (up to 40 mg per day) in a 9‐month protocol.

Outcome Measures.—Monthly headache index calculated as the mean of pain ratings (0 to 10 scale) recorded by participants in a diary 4 times per day, number of days per month with at least moderate pain (pain rating of 5 or greater), and analgesic medication use.

Results.—In patients who had not responded to amitriptyline, paroxetine failed to reduce chronic tension‐type headaches or analgesic medication use. In patients who had not responded to placebo, paroxetine produced modest reductions in chronic tension‐type headaches and analgesic use.

Conclusions.—We found no evidence that chronic tension‐type headaches that failed to respond to tricyclic antidepressant therapy with amitriptyline improved when subsequently treated with paroxetine. More support was found for the efficacy of paroxetine in patients with chronic tension‐type headaches who had failed to respond to placebo.
Total Anomalous Pulmonary Venous Draining to Inferior Vena Cava
Authors: Wang Z. P. , Zhong F. , Huang L. B. , Zhao W. , Huang W. M.
Published: September 2003

A 12-year-old girl complained of tachycardia and dyspnea after exertion but without cyanosis. Her echocardiogram showed an ASD and a widened inferior vena cava. A difference in PO2 between inferior and superior vena cava was evident. An anastomosis between left atrium and pulmonary vein, and a long oval pericardium to cover the opening of the descending vein and ASD into left atrium were performed during cardiopulmonary bypass. The patient recovered without complications.
Isotropic–nematic phase behavior of length-polydisperse hard rods
Authors: Wensink H. H. , Vroege G. J.
Published: September 2003

The isotropic–nematic phase behavior of length-polydisperse hard rods with arbitrary length distributions is calculated. Within a numerical treatment of the polydisperse Onsager model using the Gaussian trial function ansatz we determine the onset of isotropic–nematic phase separation, coming from a dilute isotropic phase and a dense nematic phase. We focus on parent systems whose lengths can be described by either a Schulz or a “fat-tailed” log-normal distribution with appropriate lower and upper cutoff lengths. In both cases, very strong fractionation effects are observed for parent polydispersities larger than roughly 50%. In these regimes, the isotropic and nematic phases are completely dominated by, respectively, the shortest and the longest rods in the system. Moreover, for the log-normal case, we predict triphasic isotropic–nematic–nematic equilibria to occur above a certain threshold polydispersity. By investigating the properties of the coexisting phases across the coexistence region for a particular set of cutoff lengths we show that the region of stable triphasic equilibria does not extend up to very large parent polydispersities but closes off at a consolute point located not far above the threshold polydispersity. The experimental relevance of the phenomenon is discussed.
Scanning tunneling microscopy and spectroscopy of gallium oxide deposition and oxidation on GaAs(001)-c(2×8)/(2×4)
Authors: Hale M. J. , Yi S. I. , Sexton J. Z. , Kummel A. C. , Passlack M.
Published: September 2003

The surface structures formed upon deposition of O2 and Ga2O onto the technologically important arsenic-rich GaAs(001)-c(2×8)/(2×4) surface have been studied using scanning tunneling microscopy and spectroscopy, and the results are compared to density functional theory calculations. O2 chemisorbs by displacing first layer arsenic atoms bonded to second layer gallium atoms. Oxygen chemisorption pins the Fermi level at less than 5% monolayer coverage by creating a donor and acceptor site within the band gap originating from the gallium atom bonded between the two O atoms. In contrast, Ga2O chemisorbs by inserting into arsenic dimer pairs at elevated surface temperatures. A monolayer of Ga2O forms a (2×2) surface structure with a crystalline interface that is electronically unpinned: there are no states within the band gap. The unpinned interface results from Ga2O restoring the surface arsenic and gallium atoms to near-bulk charge.
Molecular properties of protonated homogeneous and mixed carbon oxide and carbon dioxide clusters
Authors: Szymczak Jaroslaw J. , Roszak Szczepan , Gora Robert W. , Leszczynski Jerzy
Published: September 2003

The molecular structures and characteristics of CO and CO2 protonated homogeneous and mixed complexes were studied by theoretical, ab initio calculations. The thermodynamics, vibrational properties, charge distribution, and interaction energy decomposition components are investigated as a function of the increasing size of clusters. The study reveals the similarities and differences between homogeneous protonated carbon oxide and protonated carbon dioxide clusters. In the first-order approximation the structural differences between (CO)nH+ and (CO2)nH+ clusters are the consequence of the electronic charge distribution in the protonated OCH+ and OCOH+ core fragments. The symmetry of protonated dimers, constituting the cationic core of clusters is the second important factor in determining the overall structure of extended complexes. The OCH+ as well as the OCOH+ fragments are stabilized by cluster formation. The structures and energetics of complexes emerge as a balance between competing electrostatic, exchange, and covalent interactions. The directional covalent forces prevail and enforce the structure of the complexes, however. A universal approach is proposed which allows for the computation of interaction energies for chemical reactions involving significant relaxation of the reactants.
Influence of band folding in InAs/GaSb superlattices
Authors: Tilton M. L. , Dente G. C.
Published: September 2003

We demonstrate the importance of accurate full zone fits for the band diagrams of constituent materials in the superlattice empirical pseudopotential method (SEPM) modeling of InAs/GaSb type-II strained superlattices. In particular, we show that inaccurate fits to X-valley energies in the constituent GaSb conduction band can lead to significant errors in the prediction of the primary band gaps of these superlattices. Specifically, we examine a set of five samples, each with a fixed InAs layer thickness of six monolayers. These samples show a strong blueshift of the band gap as the GaSb layer thickness is systematically increased. We demonstrate that the superlattice-induced band folding of the GaSb conduction band X valley significantly influences our theoretically predicted results for the shorter-period superlattice samples. This result helps shed light on the proper domain of application of heterostructure theories, such as effective mass theories, that only involve zone center properties of the constituent materials.
Temperature independent physisorption kinetics and adsorbate layer compression for Ar adsorbed on Pt(111)
Authors: Kimmel Greg A. , Persson Mats , Dohnálek Z. , Kay Bruce D.
Published: September 2003

The influence of adlayer compression on the physisorption of Ar on Pt(111) is investigated using temperature programmed desorption and modulated molecular beams. We find that the difference in coverage between the compressed and uncompressed first layers is ∼10–15%. For coverages near one monolayer, this compression causes nearly temperature independent desorption kinetics over a wide temperature range (32–41 K). We present a theory that includes the effects of the compression on the desorption kinetics and explains the observed kinetics in terms of a competition between adsorbate–substrate and adsorbate–adsorbate interactions resulting in a continuous increase in the chemical potential near the completion of each successive layer.
Structures and aromaticities of carbon-rich semiconductor microclusters GelSimCn: An ab initio study
Authors: Li Si-Dian , Yu Hong-Lang , Wu Hai-Shun , Jin Zhi-Hao
Published: September 2003

Density functional theory and second-order Moller–Plesset perturbation theory investigations show that carbon-rich semiconductor microclusters GelSimCn (7⩽s=l+m+n⩽10 with n=5–8) possess linear or planar structures and the aromaticity of the singly- or doubly charged H-saturated planar derivatives with (4n+2) delocalized π electrons decreases with the increasing of noncarbon atoms.
Ab initio theoretical studies of potential energy surfaces in the photodissociation of the vinyl radical. I. Ã state dissociation
Authors: Zhang Peng , Irle Stephan , Morokuma Keiji , Tschumper Gregory S.
Published: September 2003

The mechanism of photodissociation of the vinyl radical, C2H3, starting from the first doublet excited (D1,Ã) state was studied with high-level ab initio methods as well as with ab initio direct dynamics. Geometry optimizations of stationary points and surface crossing seams were performed with complete active space self-consistent field (CASSCF) method, and the energies were re-evaluated with single-point multireference single and double excitation configuration interaction (MRCISD) calculations. Both internal conversion and intersystem crossing channels, which could bring the excited vinyl radical down to the ground state potential energy surface leading to dissociation on the ground state, have been identified within planar Cs, twisted Cs and C2v symmetry. Direct dynamics calculation indicates that the most feasible reaction channel is the direct internal conversion from D1 to the ground state (D0) within planar Cs symmetry, through a minimum of seam of crossing (conical intersection) at an energy of about 80 kcal/mol (with respect to the ground-state equilibrium geometry). The other internal conversions from D1 to D0 through conical intersections within twisted Cs symmetry require energies of about 80 and 75 kcal/mol at the two minima of seam of crossing, respectively, and they are not favored dynamically without initial out-of-plane vibrational excitation. The intersystem crossing channels between D1 and the lowest quartet state (Q1) and D0 and Q1 within twisted Cs and C2v symmetry are not efficient due to the high energy of the minima of seam of crossing as well as the small spin–orbit coupling.
Effect of deposition conditions of poly Si1−xGex films and Ge atoms on the electrical properties of poly Si1−xGex (x=0,0.6)/HfO2 gate stack
Authors: Kang Sung Kwan , Nam Suheun , Min Byoung Gi , Nam Seok Woo , Ko Dae-Hong , Cho Mann-Ho
Published: September 2003

The effect of interfacial reactions at the poly Si1−xGex/HfO2 interface on the electrical properties of metal–oxide–semiconductor (MOS) capacitors with a poly Si1−xGex (x=0,0.6)/HfO2 gate stack was investigated relative to the deposition conditions for the poly Si1−xGex films, the Ge content of the poly Si1−xGex films, and the annealing temperatures, by the electrical measurements and x-ray photoelectron spectroscopy. With an increase in hydrogen induced from doping or from deposition gas used during the deposition of poly Si1−xGex (x=0,0.6) films, the accumulation capacitance of the MOS capacitors with a poly Si1−xGex/HfO2 gate stack became anomalous and the leakage current increased significantly, due to the formation of hydroxyl(OH–) ions or the partial reduction of HfO2 at the grain boundary. With an increase in Ge content of the poly Si1−xGex films, silicate formation became dominant at the poly Si1−xGex/HfO2 interface, resulting in a significant decrease in leakage current.
Tunable nonlinear current–voltage characteristics of three-terminal ballistic nanojunctions
Authors: Shorubalko I. , Xu H. Q. , Omling P. , Samuelson L.
Published: September 2003

The current–voltage (I–V) characteristics of three-terminal ballistic junctions (TBJs) fabricated from high-electron-mobility GaInAs/InP quantum-well structures are measured in the six-terminal configuration. These characteristics show strong nonlinear, diode-like behavior, in agreement with recent theoretical calculations. Furthermore, the I–V characteristics are tunable by the voltage applied directly to one branch of the TBJs acting as a gate. An additional tuning of the characteristics of the TBJ devices can be performed using an in-plane side gate. All the presented characteristics are measured at room temperature, which makes TBJ devices promising for future nanoelectronic applications.
Structural transformation of methane hydrate from cage clathrate to filled ice
Authors: Ikeda Takashi , Terakura Kiyoyuki
Published: September 2003

The structural, dynamical, and electronic properties of methane hydrate under pressure and at room temperature are investigated using the ab initio constant pressure molecular dynamics method. Cage structures in cubic structure I are destroyed at 4.5 GPa. After the breakdown of cage structures water molecules form a channel surrounding a chain of methane molecules prominent in MH-III. In our MH-III there exists a single peak of C-D stretching mode showing blueshift in agreement with experiment. Our study supports the existence of “filled ice” proposed by Loveday et al. [Phys. Rev. Lett. 87, 215501 (2001)].
High quality type II InAs/GaSb superlattices with cutoff wavelength ∼3.7 μm using interface engineering
Authors: Wei Yajun , Bae Junjik , Gin Aaron , Hood Andrew , Razeghi Manijeh , Brown Gail J. , Tidrow Meimei
Published: September 2003

We report the most recent advance in the area of type II InAs/GaSb superlattices that have cutoff wavelength of ∼3.7 μm. With GaxIn1−x type interface engineering techniques, the mismatch between the superlattices and the GaSb (001) substrate has been reduced to <0.1%. There is no evidence of dislocations using the best examination tools of x-ray, atomic force microscopy, and transmission electron microscopy. The full width half maximum of the photoluminescence peak at 11 K was ∼4.5 meV using an Ar+ ion laser (514 nm) at fluent power of 140 mW. The integrated photoluminescence intensity was linearly dependent on the fluent laser power from 2.2 to 140 mW at 11 K. The temperature-dependent photoluminescence measurement revealed a characteristic temperature of one T1=245 K at sample temperatures below 160 K with fluent power of 70 mW, and T1=203 K for sample temperatures above 180 K with fluent power of 70 and 420 mW.
Electronic structure studies of the buried Ni layer in a Cu/Ni/Cu multilayer by resonant photoemission at the Ni L3 edge
Authors: Jung Ranju , Koh Hoon , Lee Jae Yong , You Dong Gyun , Choi Wonhoon , Kim Changyoung
Published: September 2003

The electronic structure of the buried Ni layer in a Cu 20 Å/Ni 50 Å/Cu 2000 Å/Si(100) multilayer system has been studied by means of resonant photoemission spectroscopy at the Ni L3 (2p3/2→3d) absorption edge. Information on the electronic structure was extracted by utilizing the difference spectrum between the on- and off-resonance spectra as well as the relatively larger escape depth of the valence band photoelectron at the excitation energy of the Ni L3 absorption edge compared to that at 3p→3d edge. The extracted 3d band of the intervening Ni layer shows an enhanced structure around 2–4 eV compared to that of pure Ni metal, and is attributed to the hybridization effect with Cu. Application of this method in combination with circularly polarized light could provide opportunities for spin sensitive experiments on more realistic magnetic material systems.
Heating in mesa structures
Authors: Fenton J. C. , Gough C. E.
Published: September 2003

Analytic and computational methods are used to consider the effects of heating on I–V measurements on commonly used mesa structures fabricated from single crystals of highly anisotropic superconductors. We address the time dependence of the temperature rise as well as its ultimate value and discuss the relative advantages for measurements of employing small mesa size, short pulses, and ns-to-μs measurements.
Photoluminescence behaviors from stoichiometric gadolinium oxide films
Authors: Zhou Jian-ping , Chai Chun-lin , Yang Shao-yan , Liu Zhi-kai , Song Shu-lin , Chen Nuo-fu , Lin Lan-ying
Published: September 2003

Stoichiometric gadolinium oxide thin films have been grown on silicon (100) substrates with a low-energy dual ion-beam epitaxial technique. Gadolinium oxide shares Gd2O3 structures although the ratio of gadolinium and oxygen in the film is about 2:1 and a lot of oxygen deficiencies exist. Photoluminescence (PL) measurements have been carried out within a temperature range of 5–300 K. The detailed characters of the PL emission integrated intensity, peak position, and peak width at different temperature were reported and an anomalous photoluminescence behavior was observed. The character of PL emission integrated intensity is similar to that of some other materials such as porous silicon and silicon nanocrystals in silicon dioxide. Four peaks relative to α band and β band were observed also. Therefore we suggest that the nanoclusters with the oxygen deficiencies contribute to the PL emission and the model of singlet-triplet exchange splitting of exciton was employed for discussion.
Effect of spin orbit on the electronic properties of zinc-blende compounds
Authors: Al-Douri Y. , Khenata R. , Chelahi-Chikr Z. , Driz M. , Aourag H.
Published: September 2003

The empirical pseudopotential method with spin-orbit splitting is used to calculate the band structure of AlSb, GaSb, ZnTe, and CdTe. The electronic band structures appear direct gap. We have tested recent empirical model of ionicity factor under effect of spin–orbit interaction. A sensitive effect of spin orbit is shown on the band structures of these compounds but does not display structural phase transition. Reasonable agreement is obtained between our calculated and other experimental results.
Capacitance–voltage characteristics of NaNbO3 thin films
Authors: Lingwal Vijendra , Panwar N. S.
Published: September 2003

By radio-frequency magnetron sputtering of bulk NaNbO3 pellet targets, films of NaNbO3 have been deposited on silicon substrates at different temperatures. Room-temperature deposited films have been annealed at different temperatures. Film samples have been characterized using an x-ray diffraction method. The room-temperature deposited films show a crystalline structure with different orientations, and films deposited at 225 and 270 °C show a crystalline structure with a single-face orientation. Films deposited at 300 °C and higher temperatures show an amorphous nature. Annealing up to 500 °C changes the orientation of the room-temperature deposited films, and annealing at and beyond 600 °C results in amorphous films. Capacitance–voltage measurements have been carried out in a metal–insulator–semiconductor configuration by sandwiching a NaNbO3 film between aluminum and silicon. Structural and capacitance–voltage characteristics of the films have been found to be sensitive to sodium and oxygen stoichiometry. Hysteresis in the capacitance–voltage measurements indicates hole injection in the annealed films and electron injection in the films deposited at different temperatures. From the observed characteristics, the capacitance of the accumulation region, capacitance of inversion region, flat-band capacitance, flat-band voltage, amount of hysteresis, density of states, density of interface states, dielectric constant, maximum capacitance of depletion layer, and maximum depletion width have been calculated for the prepared samples. In the crystalline films, with increasing deposition or annealing temperature, the dielectric constant tends to that of the bulk. The charge storage capacity, charge storage density, density of states, and density of interface states for NaNbO3-assisted metal–insulator–semiconductor structure have been found to be quite larger as compared to reported values for other materials, which suggests the superior potential of NaNbO3 films for memory applications.
Auger mechanism of exoelectron emission in dielectrics with high electron affinity
Authors: Molotskii M. , Naich M. , Rosenman G.
Published: September 2003

A theory of the Auger mechanism of thermally stimulated exoelectron emission from dielectrics with deep electron traps and high electron affinity is proposed. The rate and the effective radius of Auger ionization, emission kinetics, and glow curves are calculated. It is shown that increasing the electron trap density leads to a gradual decrease in the order of the emission kinetics from 3 to 2. The glow curves are used to determine the energy levels of defect states from the exoelectron emission experiments on amorphous silicon nitride thin films. The data obtained corresponds to other experimental results.
Three-dimensional simulation of rapid melting and resolidification of thin Si films by excimer laser annealing
Authors: Kisdarjono Hidayat , Voutsas Apostolos T. , Solanki Raj
Published: September 2003

A model has been developed for the rapid melting and resolidification of thin Si films induced by excimer-laser annealing. The key feature of this model is its ability to simulate lateral growth and random nucleation. The first component of the model is a set of rules for phase change. The second component is a set of functions for computing the latent heat and the displacement of the solid–liquid interface resulting from the phase change. The third component is an algorithm that allows for random nucleation based on classical nucleation theory. Consequently, the model enables the prediction of lateral growth length (LGL), as well as the calculation of other critical responses of the quenched film such as solid–liquid interface velocity and undercooling. Thin amorphous Si films with thickness of 30, 50, and 100 nm were annealed under various laser fluences to completely melt the films. The resulting LGL were measured using a scanning electron microscope. Using physical parameters that were consistent with previous studies, the simulated LGL values agree well with the experimental results over a wide range of irradiation conditions. Sensitivity analysis was done to demonstrate the behavior of the model with respect to a select number of model parameters. Our simulations suggest that, for a given fluence, controlling the film’s quenching rate is essential for increasing LGL. To this end, the model is an invaluable tool for evaluating and choosing irradiation strategies for increasing lateral growth in laser-crystallized silicon films.
Schottky barriers at metal-finite semiconducting carbon nanotube interfaces
Authors: Xue Yongqiang , Ratner Mark A.
Published: September 2003

Electronic properties of metal-finite semiconducting carbon nanotube interfaces are studied as a function of the nanotube length using a self-consistent tight-binding theory. We find that the shape of the potential barrier depends on the long-range tail of the charge transfer, leading to an injection barrier thickness comparable to half of the nanotube length until the nanotube reaches the bulk limit. The conductance of the nanotube junction shows a transition from tunneling to thermally activated transport with increasing nanotube length.
Effect of root-zone temperatures on morphology, growth and development, yield, and yield components of annual medics
Authors: Dehaghi Majid Amini , Sanavy Seyed Ali Mohammad Modarres
Published: September 2003

Annual medic pastures are an effective component of ley-farming systems (cereal–legume rotations) in Australian areas with a Mediterranean climate, but they have been unsuccessful in areas near the Mediterranean Sea. In some zones with a Mediterranean climate, like Iran and Syria, root-zone temperature is considered the major growth-limiting factor for annual medic early in the growing season. In order to study the effect of low root-zone temperature (RZT) on growth and development, yield, and yield components of some annual Medicago species, an experiment was conducted in a controlled-environment chamber. In this experiment, 3 species of annual medics, namely Medicago polymorpha, M. radiata, and M. rigidula, thought to be adapted to cold and temperate conditions, were used. Four root-zone temperatures (5, 10, 15, and 20�C) were considered. The experimental layout was a completely randomised block design with 4 replications. There were differences among the annual medics for dry matter and yield components. Two species, M. polymorpha and M. rigidula, had more leaf, stem, and root dry matter, plant height, leaf and stem to root ratio, leaf to stem ratio, and leaf area and yield than M. radiata. Therefore, M. polymorpha and M. rigidula may be better suited for ley-farming systems in cold and temperate zones. The results also showed that the 5�C RZT effectively decreased the yield and yield components of the annual medics. In conclusion, application of ley-farming is not likely to be successful when RZT is below 5�C, especially during vegetative development. Therefore, in the zones where soil temperature is greater than 10�C, annual medics have normal growth and produce average yields. Ley-farming (cereal–legume rotation) could be replaced with fallow–cereal rotation.
The effect of ration sequence on the staple strength of genetically high and low wool producing Merino wethers
Authors: Friend M. A. , Robards G. E.
Published: September 2003

A controlled feeding experiment, designed to maintain liveweight while changing dietary crude protein content, was conducted with medium wool Merino wethers of high (fleece-plus) and low (fleece-minus) wool growing capacity. The sheep were split into 3 groups and offered a ration of medium (17%) protein content throughout the experiment (Control), a sequence in which the ration changed from medium to high (27%) then low (7%) protein content, or a ration sequence of medium–low–high protein content. While diets were offered at a level designed to be isoenergetic, incomplete intake of the low protein ration resulted in the energy intake of sheep receiving this ration being significantly (P < 0.05) less than the energy intake of sheep receiving the other two rations.Feeding regime significantly influenced staple strength of fleece-plus, but not fleece-minus sheep. Fleece-plus sheep receiving the ration sequence that changed from medium to low to high protein content grew wool with significantly (P < 0.05) lower staple strength than fleece-plus sheep receiving either of the other ration sequences. Liveweight changes throughout the experiment were small and did not explain any of the variance in staple strength. Analysis of fibre diameter profiles measured using autoradiography indicated along-fibre variation in diameter was influenced by genotype and feeding sequence, while between-fibre variation in diameter was influenced by feeding sequence only. Regression analysis indicated two models, one containing between-fibre variation in diameter and standard deviation of fibre diameter, and another including along-fibre variation in diameter, rate of fibre diameter increase during ration changes, and clean fleece weight explained a significant part of the variation in staple strength. The results are discussed in relation to mechanisms affecting staple strength.
Does soil texture influence the distribution of the greyback canegrub, Dermolepida albohirtum (Waterhouse) (Coleoptera: Scarabaeidae), in the Burdekin River sugarcane growing area?
Authors: Ward Andrew L.
Published: September 2003

A series of experiments was undertaken to examine the effect of soil type on the spatial distribution of greyback canegrub in sugarcane in the Burdekin region of Queensland. These experiments examined spatial distribution at a district level as well as within individual fields, using both field and laboratory experiments. The studies concluded that soil type affected canegrub distribution both within fields and within the Burdekin district. However, the mechanisms affecting the distribution at each level were very different. At a regional or district level the preference of greyback canegrub for sandy delta-type soils over soil with higher clay content was hypothesised to be the result of preferential oviposition and improved larval survival in sandy soils over soils with a high clay content. At the field level, cane height was thought to be the primary reason for the patchy distribution of damage, with taller areas being damaged in preference to shorter areas. As all cane is planted or harvested at the same time in each field, differences in cane height between damaged and undamaged areas were thought to be the result of differences in soil type.
Improved in ovulo embryo culture for stenospermocarpic grapes (Vitis vinifera L.)
Authors: Liu S. M. , Sykes S. R. , Clingeleffer P. R.
Published: September 2003

In ovulo embryo rescue techniques have been used to recover new hybrids from seedless × seedless grape crosses. This study was conducted to increase efficiency by investigating effects of genotype, medium, and ovule removal age on ovule elongation, embryo recovery, growth, and plantlet formation. Ovules from self-pollinated berries of seedless varieties Sunmuscat, Merbein Seedless, and Marroo Seedless were cultured at 30, 43, 60, and 70 days after flowering (DAF) in a range of media, some of which were supplemented with gibberellic acid (GA3) and indole-3-acetic acid (IAA). The effect of activated charcoal (AC) in media on rescued embryos was also investigated. Ovules exhibited continuous growth in vivo and in vitro. The most vigorous growth was observed for ovules cultured at 30 and 43 DAF, but more embryos were recovered from ovules cultured at 60 and 70 DAF. Ovule growth and embryo production in vitro were improved in Bouquet and Davis (BD) and Nitsch and Nitsch (NN) media. Supplementation with GA3 increased embryo recovery rates. Highest embryo recovery rates were 18.1%, 9.6%, and 12.2% for Sunmuscat, Merbein Seedless, and Marroo Seedless, respectively, when ovules were excised and cultured at 60 or 70 DAF in either BD or NN media. In vitro embryo survival and plantlet formation were higher for torpedo-shaped embryos, and improved greatly in 6-benzyladenine (BA)-supplemented woody plant (WP) medium containing 0.3% AC. Embryo recovery was improved by excising and culturing ovules at 60 DAF in BD or NN media and then by transferring embryos to WP medium supplemented with BA and AC.
Characterisation of glyphosate uptake into grass species
Authors: Liu Z. Q.
Published: September 2003

The effect of surfactant ethylene oxide (EO) content, droplet spread area, and the active ingredient (a.i.) dose on the leaf surface on glyphosate uptake into 3 grass species (wheat, ryegrass, and barnyard grass) was investigated. It was found that glyphosate uptake into wheat was only moderately correlated (R2 = 0.66) with surfactant EO content (range 5–20 units per molecule). By contrast, a highly negative correlation (R2 = 0.98) was found between the uptake and the spread area of the treatment formulations on the leaf surface. The influence of droplet spreading on glyphosate uptake was further investigated using a super-spreading surfactant, Silwet L-77, and varying a.i. concentrations. It was demonstrated that the determining factor for glyphosate uptake into all 3 grass species was the a.i. dose (in μg/mm2) formed on the leaf surface after droplet spreading. Droplet spread area per se had only an indirect effect on the uptake through diluting the a.i. dose. In the presence of a non-spreading surfactant, Mon 0818, glyphosate uptake depended not only on the a.i. dose but also the surfactant dose on the leaf surface. In the absence of surfactants, high a.i. dose alone was not enough to ensure a high level uptake. The results are discussed in relation to the current knowledge on the interactions between surfactants and herbicide uptake.
Pathogenic specialisation within Colletotrichum trifolii in Australia, and lucerne cultivar reactions to all known Australian pathotypes
Authors: Mackie J. M. , Musial J. M. , O'Neill N. R. , Irwin J. A. G.
Published: September 2003

Anthracnose and crown rot, caused by Colletotrichum trifolii, are serious diseases of lucerne (Medicago sativa L.) in humid regions of the world. A race survey was conducted by inoculating individual lucerne clones (genotypes) with C. trifolii isolates collected from a range of Medicago hosts, locations, and years in south-eastern Queensland. This survey revealed for the first time in Australia the presence of race 2 (virulence on anthracnose resistance gene An1) and the first world report of race 4 (virulence on An2). A collection of North American race 1 and race 2 C. trifolii isolates, when inoculated onto the Australian differential clones, gave responses that were in agreement with their North American reactions. A RAPD analysis was conducted on 9 Australian C. trifolii isolates including races 1, 2, and 4; two C. destructivum and one C. gloeosporioides isolate were included as known outliers. For the C. trifolii isolates, 94.6% similarity was found regardless of host origin or race, compared with 2.2% similarity between this group and the C. gloeosporioides and C. destructivum isolates, confirming that the new races belong to C. trifolii. Currently, it is hypothesised that only plants carrying genes An1 and An2 are resistant to the 3 races. Of 22 cultivars screened against the 3 races, only UQL-1, Hallmark, and Pioneer 54Q53 had >30% of plants resistant to the 3 races in separate screenings. The research highlights the need to find new sources of resistance to C. trifolii in lucerne.
Taurus Tunable Filter — Seven Years of Observing
Authors: Bland-Hawthorn J. , Kedziora-Chudczer L.
Published: September 2003

The Taurus Tunable Filter (TTF) has now been in regular use for seven years on the Anglo–Australian Telescope (AAT). The instrument was also used for three years (1996–1999) on the William Herschel Telescope (WHT). We present a brief review of the different applications in order to illustrate the versatility of tunable filters in optical/IR spectrophotometric imaging. Tunable filters are now either planned or under development for 6–10 m class telescopes which ensures their use for years to come.
Production of Aluminium and the Heavy Magnesium Isotopes in Asymptotic Giant Branch Stars
Authors: Karakas A. I. , Lattanzio J. C.
Published: September 2003

We investigate the production of aluminium and magnesium in asymptotic giant branch models covering a wide range in mass and composition. We evolve models from the pre-main sequence, through all intermediate stages, to near the end of the thermally-pulsing asymptotic giant branch phase. We then perform detailed nucleosynthesis calculations from which we determine the production of the magnesium and aluminium isotopes as a function of the stellar mass and composition. We present the stellar yields of sodium and the magnesium and aluminium isotopes. We discuss the abundance predictions from the stellar models in reference to abundance anomalies observed in globular cluster stars.
Long-duration Coherent Radio Emission from the dMe Star Proxima Centauri
Authors: Slee O. B. , Willes A. J. , Robinson R. D.
Published: September 2003

The Australia Telescope and Anglo-Australian Telescope were used in May 2000 to record the radio and optical emissions from the dMe flare star Proxima Centauri. Eight bright optical flares over a two-day interval resulted in no detectable excess short-term radio emission at 1.38 and 2.50 GHz. However, a slowly declining 1.38 GHz emission over the two-day interval was nearly 100% right circular polarised and was restricted to a relatively narrow bandwidth with total intensity (I) and circular polarisation (V) varying significantly over the 104 MHz receiver bandwidth. These are the first observations to show that highly-polarised narrowband flare star emission can persist for several days. This signature is attributed to sources of coherent radio emission in the star's corona. Similarities with various solar radio emissions are discussed; however, it is not possible with the existing observations to distinguish between fundamental plasma emission and electron–cyclotron maser emission as the responsible mechanism.
The Radio–FIR Correlation: Is MHD Turbulence the Cause?
Authors: Groves Brent A. , Cho Jungyeon , Dopita Michael , Lazarian Alex
Published: September 2003

The radio–far infrared correlation is one of the tightest correlations found in astronomy. Many of the models explaining this correlation rely on the association of global magnetic field strength with gas density. In this letter we put forward that the physical reason for this association lies within the processes of magnetohydrodynamic turbulence.
A New Procedure for the Photometric Parallax Estimation
Authors: Karaali S. , Karataş Y. , Bilir S. , Ak S. G. , Hamzaoğlu E.
Published: September 2003

We present a new procedure for photometric parallax estimation. The data for 1236 stars provide calibrations between the absolute magnitude offset from the Hyades main-sequence and the ultraviolet-excess for eight different (B–V)0 colour-index intervals, (0.3 0.4), (0.4 0.5), (0.5 0.6), (0.6 0.7), (0.7 0.8), (0.8 0.9), (0.9 1.0) and (1.0 1.1). The mean difference between the original and estimated absolute magnitudes and the corresponding standard deviation are rather small, +0.0002 and ±0.0613 mag. The procedure has been adapted to the Sloan photometry by means of colour equations and applied to a set of artificial stars with different metallicities. The comparison of the absolute magnitudes estimated by the new procedure and the canonical one indicates that a single colour–magnitude diagram does not supply reliable absolute magnitudes for stars with large range of metallicity.
Is High-Velocity Cloud Complex C Associated with the Galactic Warp?
Authors: Kawata Daisuke , Thom Christopher , Gibson Brad K.
Published: September 2003

We test the hypothesis that high-velocity gas cloud Complex C is actually a high-latitude spiral arm extension in the direction of the Galactic warp, as opposed to the standard interpretation — that of a once extragalactic, but now infalling, gas cloud. A parallel Tree N-body code was employed to simulate the tidal interaction of a satellite perturber with the Milky Way. We find that a model incorporating a perturber of the mass of the Large Magellanic Cloud on a south to north polar orbit, crossing the disk at ˜15 kpc, does yield a high-velocity, high-latitude extension consistent with the spatial, kinematical, and column density properties of Complex C. Unless this massive satellite remains undiscovered because of either a fortuitous alignment with the Galactic bulge (feasible within the framework of the model), or the lack of any associated baryonic component, we conclude that this alternative interpretation appears unlikely.
Australia's Role in Gravitational Wave Detection
Authors: Jacob John S. , Barriga Pablo , Blair David G. , Brooks Aidan , Burman Ron , Burston Raymond , Chan Lee , Chan XiuTing , Chin Eu-Jeen , Chow Jong , Coward David , Cusack Benedict , de Vine Glen , Degallaix Jerome , Dumas Jean-Charles , Faulkner Angus , Garoi Florin , Gras Slawomir , Gray Malcolm , Hamilton Murray , Herne Matthew , Hollitt C. , Hosken David , Howell Eric , Ju Li , Kelly T. , Lee Ben , Lee Chuen Ying , Lee Kah Tho , Lun Antony , McClelland David , McKenzie Kirk , Mow-Lowry C. , Mudge Damien , Munch Jesper , Paget Darren , Schediwy Sascha , Scott Susan , Searle Antony , Sheard Ben , Slagmolen Bram , Veitch Peter , Winterflood John , Woolley Andrew , Yan Zewu , Zhao Chunnong
Published: September 2003

An enormous effort is underway worldwide to attempt to detect gravitational waves. If successful, this will open a new frontier in astronomy. An essential portion of this effort is being carried out in Australia by the Australian Consortium for Interferometric Gravitational Astronomy (ACIGA), with research teams working at the Australia National University, University of Western Australia, and University of Adelaide involving scientists and students representing many more institutions and nations. ACIGA is developing ultrastable high-power continuous-wave lasers for the next generation interferometric gravity wave detectors; researching the problems associated with high optical power in resonant cavities; opening frontiers in advanced interferometry configurations, quantum optics, and signal extraction; and is the world's leader in high-performance vibration isolation and suspension design. ACIGA has also been active in theoretical research and modelling of potential astronomical gravitational wave sources, and in developing data analysis detection algorithms. ACIGA has opened a research facility north of Perth, Western Australia, which will be the culmination of these efforts. This paper briefly reviews ACIGA's research activities and the prospects for gravitational wave astronomy in the southern hemisphere.
A Distributed Data Implementation of the Perspective Shear-Warp Volume Rendering Algorithm for Visualisation of Large Astronomical Cubes
Authors: Beeson Brett , Barnes David G. , Bourke Paul D.
Published: September 2003

We describe the first distributed data implementation of the perspective shear-warp volume rendering algorithm and explore its applications to large astronomical data cubes and simulation realisations. Our system distributes sub-volumes of 3-dimensional images to leaf nodes of a Beowulf-class cluster, where the rendering takes place. Junction nodes composite the sub-volume renderings together and pass the combined images upwards for further compositing or display. We demonstrate that our system out-performs other software solutions and can render a 'worst-case' 512 × 512 × 512 data volume in less than four seconds using 16 rendering and 15 compositing nodes. Our system also performs very well compared with much more expensive hardware systems. With appropriate commodity hardware, such as Swinburne's Virtual Reality Theatre or a 3Dlabs Wildcat graphics card, stereoscopic display is possible.