bluuebunny/crossref_metadata_2025 huggingface dataset:
Time-domain laser-induced fluorescence spectroscopy apparatus for clinical diagnostics
Authors: Fang Qiyin , Papaioannou Thanassis , Jo Javier A. , Vaitha Russel , Shastry Kumar , Marcu Laura
Published: December 2003

We report the design and development of a compact optical fiber-based apparatus for in situ time-resolved laser-induced fluorescence spectroscopy (tr-LIFS) of biological systems. The apparatus is modular, optically robust, and compatible with the clinical environment. It incorporates a dual output imaging spectrograph, a gated multichannel plate photomultiplier (MCP-PMT), an intensified charge-coupled-device (ICCD) camera, and a fast digitizer. It can accommodate various types of light sources and optical fiber probes for selective excitation and remote light delivery/collection as required by different applications. The apparatus allows direct recording of the entire fluorescence decay with high sensitivity (nM range fluorescein dye concentration with signal-to-noise ratio of 46) and with four decades dynamic range. It is capable of resolving a broad range of fluorescence lifetimes from hundreds of picoseconds (as low as 300 ps) using the MCP-PMT coupled to the digitizer to milliseconds using the ICCD. The data acquisition and analysis process is fully automated, enabling fast recording of fluorescence intensity decay across the entire emission spectrum (0.8 s per wavelength or ∼40 s for a 200 nm wavelength range at 5 nm increments). The spectral and temporal responses of the apparatus were calibrated and its performance was validated using fluorescence lifetime standard dyes (Rhodamin B, 9-cyanoanthracene, and rose Bengal) and tissue endogenous fluorophores (elastin, collagen, nicotinamide adenine dinucleotide, and flavin adenine dinucleotide). Fluorescence decay lifetimes and emission spectra of all tested compounds measured with the current tr-LIFS apparatus were found in good agreement with the values reported in the literature. The design and performance of tr-LIFS apparatus have enabled in vivo studies of atherosclerotic plaques and brain tumors.
Method for evaluating material viscoelasticity
Authors: Fujii Yusaku , Yamaguchi Takao
Published: December 2003

A method for evaluating the viscoelasticity of materials under oscillation load is proposed. In the method, a material under test is connected to a mass, which generates an oscillating inertial force after the mass is manually struck using a hammer. A pneumatic linear bearing is used to realize linear motion with sufficiently small friction acting on the mass that is the moving part of the bearing. The inertial force acting on the mass is determined highly accurately by means of measuring the velocity of the mass using an optical interferometer.
Theoretical study of electrical transport in a fullerene-doped semiconducting carbon nanotubes
Authors: Pati Ranjit , Senapati Laxmidhar , Ajayan Pulickel M. , Nayak Saroj K.
Published: December 2003

Using a tight-binding model and the Landauer–Büttiker formalism, we have calculated the current–voltage characteristics of a semiconducting single-walled carbon nanotube and that of a fullerene (C60)-doped carbon nanotube (peapod) structure. Our calculation shows that fullerene encapsulation in a semiconducting nanotube enhances the electrical conductivity of the nanotube, which is consistent with recent experimental measurements. We explain the increased electronic conduction in the semiconducting nanopeapod structure by analyzing the density of states of both pristine and C60-doped nanotubes. A first-principles density functional calculation shows a significant amount of charge transfer (0.62e−) from the nanotube to C60, suggesting that holes are the primary charge carriers in the peapod.
Spherical deformation of compliant substrates with semiconductor device islands
Authors: Hsu P. I. , Huang M. , Xi Z. , Wagner S. , Suo Z. , Sturm J. C.
Published: December 2003

This article explores, through experiments and finite element analysis, the ability to plastically deform thin-film semiconductor structures on deformable substrates to spherical cap shapes without cracking the semiconductor layers. The major challenge involves contending with the large strain due to extreme deformation that will crack uniform stiff layers, such as silicon or silicon nitride. By patterning amorphous silicon and silicon nitride layers into islands, such problems can be avoided despite average strains in the substrate in excess of 5%. The strain in the device islands after deformation is a function of the island structure, size, and substrate material properties. Although the substrate is plastically expanded to a spherical dome, device islands can experience either tension or compression depending on the structure.
Photoluminescence, depth profile, and lattice instability of hexagonal InN films
Authors: Semchinova O. K. , Aderhold J. , Graul J. , Filimonov A. , Neff H.
Published: December 2003

High quality InN films have been grown on (0001) sapphire substrates by metalorganic molecular beam epitaxy, characterized for crystal structure, chemical composition, and optical properties. Depth profiling indicated a high, increasing oxygen concentration profile towards the volume of the film. Photoluminescence revealed two different, coexisting features: a low energy transition around 0.8 eV, and a high energy feature, peaking near 2 eV. The former band originates from the direct transition in the near surface range. The latter, low intensity band results from the bulk region. Oxynitride formation has been accounted for a spatially varying optical band gap EG, determined to 0.61 eV for pure, defect free material. X-ray diffraction analysis supports defect mediated lattice instability, as proposed recently by a molecular dynamic lattice theory.
Magnetic and electronic structures of FePtCu ternary ordered alloy
Authors: Kai T. , Maeda T. , Kikitsu A. , Akiyama J. , Nagase T. , Kishi T.
Published: December 2003

We investigated the microscopic structure of FePtCu ternary ordered alloys from both theoretical and experimental points of view. From the theoretical viewpoint, first principles calculation was carried out based on the full-potential linear augmented plane wave method in order to obtain the electronic structure and magnetic anisotropy energy of the FePtCu ternary ordered alloy. From the experimental viewpoint, the ultraviolet photoelectron spectroscopy measurement was used to identify the Cu position in FePtCu ternary ordered alloy. From a comparison with the calculated density of states curve, it was found that the Fe site of FePt ordered alloy replaced the Cu. The theoretical and experimental results in this article support the mechanism proposed in terms of the thermodynamic considerations in our previous article.
Optical excitation of Er ions with 1.5 μm luminescence via the luminescent state in Si nanocrystallites embedded in SiO2 matrices
Authors: Makimura Tetsuya , Kondo Keiichi , Uematsu Hiroshi , Li Changqing , Murakami Kouichi
Published: December 2003

Optical excitation bands have been investigated for Er-doped SiO2 films, including Si nanocrystallites as sensitizers. The Er-doped films with photoluminescence at 1.5 μm were fabricated using a laser ablation technique. It is found that the major continuous portion of the excitation bands for Er ions completely coincides with that of Si nanocrystallites at room temperature. Thus, it has been demonstrated that the second indirect absorption band of Si nanocrystallites can be used for efficient excitation of Er ions. The photoluminescence spectroscopy revealed that Er ions are possibly excited from the ground state I15/24 to the first excited state I13/24 by the energy transfer from the singlet excitons in Si nanocrystallites.
Response function during oxygen sputter profiling and its application to deconvolution of ultrashallow B depth profiles in Si
Authors: Shao Lin , Liu Jiarui , Wang Chong , Ma Ki B. , Zhang Jianming , Chen John , Tang Daniel , Patel Sanjay , Chu Wei-Kan
Published: December 2003

The secondary ion mass spectrometry (SIMS) response function to a B “δ surface layer” has been investigated. Using electron-gun evaporation combined with liquid nitrogen cooling of target, we are able to deposit an ultrathin B layer without detectable island formation. The B spatial distribution obtained from SIMS is exponentially decaying with a decay length approximately a linear function of the incident energy of the oxygen during the SIMS analysis. Deconvolution with the response function has been applied to reconstruct the spatial distribution of ultra-low-energy B implants. A correction to depth and yield scales due to transient sputtering near the Si surface region was also applied. Transient erosion shifts the profile shallower, but beam mixing shifts it deeper. These mutually compensating effects make the adjusted distribution almost the same as original data. The one significant difference is a buried B peak observed near the surface region.
Negative differential resistance in a bilayer molecular junction
Authors: Le John D. , He Yan , Hoye Thomas R. , Mead Curtis C. , Kiehl Richard A.
Published: December 2003

Negative differential resistance (NDR) is reported for a bilayer molecular junction. The system is comprised of a Hg–alkanethiol//arenethiol–Au bilayer molecular junction formed by bringing into contact a tetradecanethiol self-assembled monolayer (SAM)-coated drop of Hg with the surface of an oligo(phenylene-ethynylene) SAM on Au. Persistent, reproducible NDR is observed in the current–voltage characteristics with peak-to-valley ratios as high as 4.5 at room temperature. These results open a promising line of investigation of structure/function relationship and mechanisms in molecular NDR components.
Excitation temperatures in the ionizing plasma of high-pressure mercury discharges
Authors: Karabourniotis Dimitrios
Published: December 2003

The excitation temperatures of mercury as well as the electron and gas temperature in two high-pressure pure-Hg discharges operated on ac have been determined by measuring the ground- and excited-state densities. The excitation temperature depends on the excited-state energy, is significantly lower than the electron temperature, and higher than the gas temperature. The differences in the temperatures are higher at the maximum current phase and for the lower pressure discharge. Comparison with the Saha densities shows that the plasma at the maximum current is in ionizing phase, whereas it is close to local thermodynamic equilibrium at the voltage zero crossing.
Reduced self-heating in Si/SiGe field-effect transistors on thin virtual substrates prepared by low-energy plasma-enhanced chemical vapor deposition
Authors: Hackbarth T. , Herzog H.-J. , Hieber K.-H. , König U. , Bollani M. , Chrastina D. , von Känel H.
Published: December 2003

This letter reports on the electrical performance of strained Si-based n-type heterostructure field-effect transistors prepared on 500 nm Si0.56Ge0.44 virtual substrates. The method of low-energy plasma-enhanced chemical vapor deposition at low temperature was used for the growth of the relaxed SiGe buffer. The active layers have been deposited by molecular-beam epitaxy. The thin buffer improves the thermal conductivity by a factor of 3 and shows a much lower surface roughness compared to control structures on conventional virtual substrate with a 5-μm-thick graded buffer. Cutoff frequencies of fT=55 GHz and fmax(U)=138 GHz have been achieved which are very close to the results of the control sample.
High-k properties of atomic-layer-deposited HfO2 films using a nitrogen-containing Hf[N(CH3)2]4 precursor and H2O oxidant
Authors: Cho Moonju , Park Hong Bae , Park Jaehoo , Lee Suk Woo , Hwang Cheol Seong , Jang Gi Hoon , Jeong Jaehack
Published: December 2003

HfO 2 thin films were deposited on HF-dipped Si wafers at 300 °C using an atomic-layer-deposition technique with N-containing Hf[N(CH3)2]4 and H2O as the precursor and oxidant, respectively. A thin interfacial SiNx layer was spontaneously formed at the HfO2/Si interface during film growth. This interfacial SiNx layer prevented substrate Si diffusion into the HfO2 film. Therefore, the reduction in the capacitance density as a result of post-annealing at 800 °C was minimized. The leakage current density was also reduced due to the more amorphous-like structure of the film. Furthermore, the interfacial trap density (Dit) of <5×1010 cm−2 eV−1 near the midgap energy states was obtained from an as-deposited film that has a capacitance equivalent thickness of 1.8 nm. This Dit value was comparable to that of the well-grown SiO2/Si interface. However, the Dit slightly increased after post-annealing as a result of the increased N concentration at the interface, but it was still <1×1011 cm−2 eV−1.
Observation of the barrier structure in magnetic tunnel junctions using high-resolution electron microscopy and electron holography
Authors: Shen F. , Zhu T. , Xiang X. H. , Xiao John Q. , Voelkl E. , Zhang Z.
Published: December 2003

Microstructures of the NiFe/AlOx/NiFe magnetic tunnel junctions and the barrier shape profile have been studied with atomic resolution using high-resolution electron microscopy and electron holography. A clear relationship between the growth morphologies of the electrodes and the quality of the barrier has been obtained. Although the bottom interface between electrode and barrier is very sensitive to the oxidation condition, a sharp interface can be achieved in optimumally oxidized junctions. The top interface, on the other hand, is always slightly oxidized due to the three-dimensional growth of top electrode above the barrier, independent of the oxidation condition of the barrier. Furthermore, charge accumulation seems to exist at the sharp interfaces. It is also interesting, yet surprising, that both interfaces are actually sharp in underoxidized junctions. Furthermore, charge accumulation seems to exist at the sharp interfaces.
Effect of nitrogen on the optical and transport properties of Ga0.48In0.52NyP1−y grown on GaAs(001) substrates
Authors: Hong Y. G. , Nishikawa A. , Tu C. W.
Published: December 2003

We report gas-source molecular-beam epitaxy of Ga1−xInxNyP1−y grown on GaAs(100) substrates. Nitrogen incorporation dramatically reduces the Ga1−xInxP band gap. With nitrogen incorporation, the photoluminescence (PL) peak energy exhibits an inverted S-shaped dependence with temperature, and the low-temperature PL spectra exhibit an asymmetric line shape with a low-energy tail. Both indicate the presence of N-related localized states, which dominate the radiative recombination processes at low temperature. N incorporation significantly reduces the free-electron concentration and mobility. The free-electron concentration of N-containing Ga0.48In0.52N0.005P0.995 decreases dramatically with high-temperature annealing (800 °C), from 4.4×1018 to 8.0×1016 cm−3. This is believed to be due to passivation of Si by N through the formation of Si–N pairs.
Soft breakdown of oxide–nitride–oxide stacked gate dielectrics used in metal–oxide–nitride–oxide–silicon-based flash memories
Authors: Okada Kenji
Published: December 2003

Degradation behavior of oxide–nitride–oxide (ONO) stacked gate dielectrics used in metal–oxide–nitride–oxide–silicon (MONOS)-based flash memories has been studied. Occurrence of the soft breakdown (SBD), which is well known in single-layer ultrathin silicon dioxides, has been revealed even in these thick and stacked dielectrics. The SBD of ONO dielectrics shows similar characteristics with that of silicon dioxides in locality, current/voltage fluctuation, and the dependencies of the ratio of SBD on the gate area and stress condition. These findings require the countermeasure for SBD even in MONOS-based flash memories and also give useful information on the reliability of high-k stacked gate dielectrics.
Broad-stripe midinfrared photonic-crystal distributed-feedback lasers with laser-ablation confinement
Authors: Bewley W. W. , Kim C. S. , Kim M. , Canedy C. L. , Lindle J. R. , Vurgaftman I. , Meyer J. R. , Muller R. E. , Echternach P. M. , Kaspi R.
Published: December 2003

We investigate broad-stripe photonic-crystal distributed-feedback lasers emitting at λ=4.4 μm. The beam quality improves dramatically when a laser ablation technique is used to eliminate parasitic Fabry–Pérot-like modes, by inducing loss in the regions adjoining the pump stripe. Even though the peak of the gain spectrum never fully aligns with the grating resonance, for pulsed pumping the output beam is essentially diffraction limited up to a stripe width of 150 μm, and remains no worse than six times the diffraction limit for stripes as broad as 400 μm.
Influence of nanocrystal growth kinetics on interface roughness in nickel–aluminum multilayers
Authors: Aurongzeb D. , Holtz M. , Daugherty M. , Berg J. M. , Chandolu A. , Yun J. , Temkin H.
Published: December 2003

We study the layer morphology of Ni/Al multilayer structures, with 50 nm period, as deposited and following 10 min anneals up through the melting temperature of Al. X-ray reflectivity measurement of the as-deposited film shows interference fringes, characteristic of a well-defined multilayer stack, with ∼1 nm interface roughness. Over a narrow anneal range of 360–500 °C these fringes diminish in amplitude and disappear, indicating elevated interface roughening. However, fringes are observed for anneal temperatures both below and above this range, indicating the presence of well-defined layers with smooth interfaces. A model, in which nanocrystal domains of intermetallic nickel aluminides form at the interfaces, is developed to quantify the annealing induced interface roughness. This model agrees well with the experimental results.
Molecular-beam epitaxy growth of arsenic film and its semimetal-to-semiconductor transition
Authors: He M. , Yuan X.-C. , Ngo N. Q. , Bu J. , Yi X. J.
Published: December 2003

Arsenic thin film was grown on a CdTe substrate by molecular-beam epitaxy. The growth process of the film was characterized in situ by reflection high-energy electron diffraction pattern and the film structure was investigated by a transmission electron microscope. The conductivity as a function of temperature was measured by the van de Pauw method. A semimetal-to-semiconductor transition in an arsenic thin film with a thickness equal to or thinner than a critical thickness of 40 nm has been observed.
Optical phase conjugation and efficient wave front correction of weak light beams by dye-doped liquid crystals
Authors: Lucchetti L. , Di Fabrizio M. , Gentili M. , Simoni F.
Published: December 2003

We report the observation of optical phase conjugation by thin nematic liquid crystal films by using submilliwatt incident power without any external applied field. The light-induced average birefringence evaluated by solving the wave equations for the four interacting waves, is in agreement with that typical of the colossal optical nonlinearity recently observed in the same materials. The high conjugated reflectivity values, obtained with the analyzed samples, allows correction of severely aberrated wave fronts of very weak light beams.
Structure, bonding, and band offsets of (100)SrTiO3–silicon interfaces
Authors: Peacock P. W. , Robertson J.
Published: December 2003

We derive rules for bonding at interfaces between Si and ionic oxides so that they satisfy valence requirements and give a defect-free interface. These rules are used to analyze epitaxial interfaces of SrTiO3 on (100)Si. The band offsets are found from the local density of states and it is found possible to modulate the offset. Some proposed interface structures are found to give gap states.
Management of soilborne diseases of beetroot in Australia: a review
Authors: Martin H. L.
Published: December 2003

Soilborne fungal diseases threaten the viability of the Australian processing beetroot industry. Globally, Pythium spp., Aphanomyces cochlioides and Rhizoctonia solani are the predominant soilborne fungal pathogens responsible for a root rot complex in beet crops. In Australia, the disease problems have been exacerbated in recent years because crops are now grown virtually year round, and under environmental conditions favourable to infection. This has lead to increased inoculum levels in soils sown to beetroot. Moreover, nowhere in the world does there seem to be a single strategy that is completely efficacious in controlling these pathogens, so an effective management strategy will almost certainly involve a combination of tactics. The most likely combination seems to involve fungicide seed treatments, rotations of gramineous or biofumigant crops and the use of disease-resistant varieties of beet. The first of these, fungicidal seed dressings, are a cost-effective means of reducing pathogen inoculum and protecting young beets from infection. Hymexazol may be particularly useful in the Australian system, since it is active against both Pythium and Aphanomyces. To combat Rhizoctonia, it should be applied in combination with either pencycuron or toclophos methyl. Second, rotations of gramineous crops, such as maize or oats, or biofumigant brassica crops, such as white mustard, brussel sprouts or cabbage should also reduce the build-up of inoculum and offers a tactic to relieve the problem in the longer term. Third, alternative beetroot cultivars with resistance to Rhizoctonia have now been developed in USA breeding programs and should be considered by the Australian industry. Resistant varieties are potentially very useful since they offer a long-term approach to disease management that can be easily incorporated into existing production systems. Fourth, the alteration of sowing dates to avoid periods of high disease risk (e.g. confining sowing to the cooler, drier months) needs to be seriously considered by the Australian industry if it is committed to disease management. There is also evidence to suggest that seed priming may warrant consideration as a tool to use in combination with fungicide dressings to reduce disease in young plants. Biological seed treatments and soil fumigation appear to be tactics of limited value to the Australian beet industry.
Aphid feeding damage causes large losses in susceptible lupin cultivars
Authors: Berlandier F. A. , Sweetingham M. W.
Published: December 2003

The impact of infestation by bluegreen aphid, Acyrthosiphon kondoi, cowpea aphid, Aphis craccivora, and/or green peach aphid, Myzus persicae, on grain production of narrow-leafed lupin (Lupinus angustifolius) and yellow lupin (Lupinus luteus) was assessed at 4 sites in the Western Australian grainbelt. Yield losses caused by naturally occurring aphids on 4 cultivars of narrow-leafed and 2 cultivars of yellow lupins were measured by applying the systemic insecticide imidacloprid as a seed dressing and/or as foliar sprays throughout the plant growth phase and compared with untreated control plots. The extent of damage caused by aphids varied greatly but was significantly influenced by lupin cultivar, and yields for the same treatment combination varied between geographical locations. Bluegreen aphid was the most abundant species wherever large colonies of aphids developed. Yellow lupin Wodjil was the most infested and suffered severe losses in grain yield, whereas narrow-leafed lupin Kalya was largely resistant to aphids and there were negligible losses in grain production from plots not treated for aphids. In a fifth experiment, a single foliar spray of the insecticide pirimicarb controlled abundant aphids and increased yield by as much as 95% (0.65 t/ha) in Wodjil. Lupin growers need to be aware of the potential losses aphids can cause and that applying foliar insecticidal sprays to susceptible cultivars can prevent such losses.
The response of canola (Brassica napus L.) to tillage and fertiliser placement in contrasting environments in southern NSW
Authors: Hocking P. J. , Mead J. A. , Good A. J. , Diffey S. M.
Published: December 2003

Land preparation for canola (oilseed rape; Brassica napus L.) by conventional cultivation can involve a number of workings, resulting in soil degradation and reduced crop growth. Minimum-tillage systems may help overcome these problems, but the placement of fertiliser at sowing must avoid chemical injury to germinating seed. The responses of canola cultivars to tillage and fertiliser placement were studied for 2 seasons at high (Breakfast Creek, 1997; Harden, 1998) and low (Ardlethan, 1997–98) rainfall sites. The tillage treatments were conventional cultivation, one-pass, and no-till (direct drill). The fertiliser treatments were 200 kg/ha 'starter' fertiliser (a�compound fertiliser supplying 30 kg N, 26 kg P and 22 kg S/ha) either placed with the seed, or broadcast, or banded to the side and 3 cm below the seed. In 1997 the canola was sown after wheat, and in 1998 after pasture. Plant establishment of all cultivars was reduced by 40–65% when fertiliser was placed with the seed; tillage treatment did not alter this response. Placing fertiliser with the seed reduced dry matter/m2 by up to 40% in plants at flowering, but by physiological maturity, there were no differences in dry matter/m2 due to fertiliser placement. Analysis of the combined seed yields for both years showed that although plants in the with-seed placement compensated by producing more seed/plant, this compensation was sufficient only at Breakfast Creek for yields to be comparable to those of the other fertiliser placements. Tillage had little effect on seed yields. In 1997, no-till yielded more than one-pass at Ardlethan, but in 1998 at Ardlethan no-till yielded less than the other tillage systems. Fertiliser placement and tillage had no effect on seed oil concentration and meal protein content. Cone penetrometer measurements (1998) showed no differences in soil strength between tillage treatments at Ardlethan; while at Harden, one-pass had less soil strength than the other tillage treatments. Crop water extraction was not affected by tillage at any site. It is concluded that a conservation-farming system involving no-till or one-pass tillage, and separation of seed and fertiliser has the potential for producing high yielding canola crops, reducing the risk of soil degradation, as well as saving time and land-preparation costs.
Evaluating pasture legumes for resistance to aphids
Authors: Nair R. M. , Craig A. D. , Auricht G. C. , Edwards O. R. , Robinson S. S. , Otterspoor M. J. , Jones J. A.
Published: December 2003

Sixteen pasture legume species from 11 genera (Astragalus, Biserrula, Hedysarum, Hymenocarpus, Lotus, Medicago, Ononis, Ornithopus, Scorpiurus, Trifolium and Trigonella) were evaluated for resistance to 3�aphid species (Therioaphis trifolii (Monell) fm. maculata, Acyrthosiphon kondoi Shinji, and Aphis craccivora Koch) at 14, 28 and 42 days after the legumes were sown in a glasshouse. Eleven of the 16 cultivars/accessions were resistant to T. trifolii, 8 were highly resistant to A. kondoi but none of the accessions or cultivars were resistant to A.�craccivora at all growth stages. Ononis alopecuroides L. and Ornithopus compressus L. were the most resistant of all plants tested. The amount of resistance to the aphids was significantly affected by the age of the plants, but was less pronounced in the case of A. kondoi.
Field performance of the M-44 ejector for red fox (Vulpes vulpes) control
Authors: Marks Clive A. , Gigliotti Frank , Busana Frank
Published: December 2003

The M-44 ejector was used to recover red foxes (Vulpes vulpes) in the eastern highlands of Victoria during two summer and two winter trials in 1997–99. Two transects containing 20 devices each were established at five independent sites. Meat baits containing rhodamine B (RB) were used in a three-week free-feeding period at each site before the ejectors were loaded with cyanide capsules and set for a further six weeks. No significant correlation was found between bodyweight and the distance from the bait station that foxes were recovered. No bias was detected in the age of either sex or the overall ratio of males to females. Bait station activity in the free-feed period was not closely correlated with the recovery of foxes at the same bait station. Comparisons with published data found no significant difference in the age structure and sex ratio of foxes recovered with the M-44 and those taken by trapping or day shooting. Nearest-neighbour distances between recovered foxes were significantly smaller in summer 1997/98 than for consecutive periods (P < 0.05). Fox recoveries were contagious in their distribution in all but the winter 1998 period. The age of foxes recovered declined from summer to winter in each year (P < 0.05) and the ratio of yearlings to adults systematically increased over the four periods. Only 39.5% of the 160 foxes recovered overall had consumed a RB-marked bait used in the three-week free-feed period, and 43% of all foxes recovered in the first week were not marked. Over a six-week recovery period in summer 1997/98 and winter 1998 there was a significant inverse relationship between time and the number of foxes recovered (P < 0.05). There was no significant difference in the slopes of the regression describing the recovery of marked and unmarked foxes during summer 1997/98, suggesting that both groups were removed at the same rate. We discuss these data with reference to the use of fox age as an indicator of control performance and suggest a simple strategy to enhance baiting efficacy when fox distribution is contagious.
Seasonal changes in home-range area and habitat use by the agile wallaby (Macropus agilis)
Authors: Stirrat Simon C.
Published: December 2003

Radio-tagged male and female agile wallabies were tracked in the wet and dry seasons at a site in Darwin, Northern Territory, and home ranges estimated using a kernel-based estimator. Home-range size (95% contour) was larger in the dry season, when food quality was poorer, and males had larger home ranges than females. Core range size (55% contour) did not differ between seasons or sexes. Average male and female home-range sizes in the wet season were 16.6 ha and 11.3 ha respectively. Wet-season core range sizes were 4.8 ha and 3.2 ha respectively. Average male and female home-range sizes in the dry season were 24.6 ha and 15.3 ha respectively, and dry-season core range sizes were 5.1 ha and 4.0 ha respectively. Home-range size for both sexes varied in the two seasons; the smallest and largest female home ranges were 6.3 ha and 24.0 ha respectively, while male home-range size varied from 7.6 ha to 38.2 ha. Seasonal differences in home-range size can be attributed to expansion of night-time foraging areas in the dry season when good-quality food resources were in short supply. Habitat use also differed between seasons. In the dry season more fixes were located in forest areas, particularly in the evening, when wallabies foraged in forest areas for alternate food resources including browse, leaf litter, flowers and fruits of rainforest tree and shrub species. In the wet season, wallabies emerged from day-time resting areas earlier in the afternoon and therefore more wallabies were located in open areas grazing on high-quality herbage in the evening.
The effect of increased ground-level habitat complexity on mouse population dynamics
Authors: Arthur A. D. , Pech R. P. , Drew A. , Gifford E. , Henry S. , McKeown A.
Published: December 2003

We investigated experimentally the influence of habitat structure on the population dynamics of house mice. Three habitat types were used. In one, dense stands of regenerating cypress pine were felled and left in situ to cover at least 40% of experimental plots, providing high complexity at ground level; in another, dense stands of regenerating pine were left intact, providing low complexity at ground level; in the third, open grassland adjacent to dense stands of regenerating pine also provided low complexity at ground level. Mouse populations occurred at higher densities in felled pine plots compared with both the standing pine and grassland plots, consistent with the hypothesis that the presence of increased habitat complexity at ground level reduced the impact of predation. Even though populations responded to the felled pine, they dropped to very low densities over winter, suggesting that the habitat was still marginal for the persistence of mice, probably due to a lack of food. The results are discussed with reference to their implications for the influence that habitat structure may have on the impact of introduced predators on native species.
Capture probability and heterogeneity of trap response in stoats (Mustela erminea)
Authors: King Carolyn M. , Davis Stephen A. , Purdey Daniel , Lawrence Barry
Published: December 2003

The technique most widely used to control the stoat, an introduced predator in New Zealand, is to set Fenn (kill) traps, usually in lines or (less often) in grids. There has been no analysis of trap response in stoats, nor of the extent of potential variation in probability of capture. We report the results of an analysis of mark–recapture data recorded from stoats observed during a period of high stoat and mouse density in January 1980 in the Eglinton and Hollyford Valleys (northern Fiordland), using livetraps set in lines at one per 400 m over 14 km in each valley. Over 8 days of trapping (1–11 January), 89 stoats were tagged. The daily probability of first capture for all ages, both sexes, was 0.14 (with 95% confidence intervals 0.07–0.25) and of recapture 0.10 (0.07–0.14).We also analysed a new set of mark–recapture data collected during a period of very low mouse density in the Grebe Valley (southern Fiordland) in December 2000, using 19 live-traps set in a line at one per kilometre over 20 km. In this study 21 adult stoats and no young of year were tagged. The daily probability of first capture for adult males was 0.12 (0.04–0.31), and of recapturing them, 0.15 (0.10–0.23). A month later, in late January 2001, 68 Fenn traps set at four per kilometre caught 48 previously unmarked stoats, plus 12 of the 21 marked stoats released alive.Heterogeneity in probability of recapture was investigated by taking a longer subset of the 1980 data (1–17 January) and grouping individuals by sex and age. In the best closed-captures models, ranked using AICc, first-capture probability was similar for all stoats (0.17 (0.12–0.24)), and evidence of variation in the probability of recapture between age and sex classes was present but weak. The confidence limits around the recapture probabilities for adult males and females overlapped completely. Recapture probabilities for young-of-the-year males remained about the same (0.14 (0.11–0.19)), while the recapture probability of young-of-the-year females halved after first capture (0.07 (0.04–0.11)).Pledger's finite-mixture models demonstrating individual heterogeneity in trappability produced lower AICc values than the closed-captures models partitioning variation in recapture probability by age and sex alone. The observed heterogeneity in trap response is therefore not due only to variable individual response to traps, but is also to opportunity, as might be expected in data collected from a line of traps where the edge effect on trap-encounter rate is high. However, the extent to which trap-encounter rate helps to explain the observed heterogeneity is unknown. Indeed, there may be other sources of individual heterogeneity that are not related to age/sex or to trap-encounter rate, and this is a potential problem for wildlife managers using conventional trap lines to remove stoats to protect native species.
Tissue residue levels in rabbits and rats poisoned with 1080 One-shot bait and the location of poisoned rabbit carcasses
Authors: Twigg Laurie E. , Lowe Tim J. , Kirkpatrick Winifred E. , Martin Gary R.
Published: December 2003

The level of fluoroacetate (1080) found in the carcasses of rats and rabbits poisoned with 1080 ranged from 1.9 to 14.4 μg g–1 (mean 5.3 μg g–1, n = 11) in rats and <0.02 to 0.78 μg g–1 (mean 0.353 μg g–1, n = 10) in rabbits. The concentration of fluoroacetate in the blood and liver of both species was generally higher than in the carcasses, and ranged from <0.02 to 33.6 μg g–1. Fifteen of 22 collared rabbits, and 3 freshly killed, uncollared rabbits were recovered during a routine baiting exercise with 1080 One-shot oats. Excluding the 4 collared rabbits taken by predators, only 14% of all carcasses (n = 14) were found in the open, with the remaining 86% of carcasses being well concealed in warrens or under thick scrub. The carcasses of both rabbits and rats showed considerable decay within 6 days of poisoning. Except for eutherian carnivores, which are highly sensitive to 1080, there is little potential risk of secondary poisoning of native wildlife as a result of the correct use of 1080 baits in pest-control programs.
Spillovers from Taiwan, Hong Kong, and Macau Investment and from Other Foreign Investment in Chinese Industries
Authors: Huang Jr‐Tsung
Published: December 2003

In its analysis of the impact of foreign investment on China's productivity, this article develops two empirical models: one using labor productivity and the other using total factor productivity (TFP). Using cross‐provincial data on Chinese industries for 1993, 1994, and 1997 to regress the empirical models, it is concluded that the impact of investment differed depending on its source, with that from these overseas Chinese enterprises contributing to the spillover effect in regions with a high technology gap, whereas that from other foreign enterprises tending to improve productivity and TFP primarily in regions with a low technology gap. (JEL D24, F13, F15, L60)
Oil Prices, Terms of Trade Shocks, and Macroeconomic Fluctuations in Saudi Arabia
Authors: Dibooğlu Sel , Aleisa Eisa
Published: December 2003

The article investigates the sources of macroeconomic fluctuations in Saudi Arabia using structural vector autoregression methods and pays particular attention to oil prices and changes in terms of trade. Using a macroeconomic model tailored to the Saudi Arabian economy, the authors identify terms of trade, supply, balance of payments, aggregate demand, and monetary shocks. The results show that the Saudi Arabian price level, real exchange rate, and to a lesser extent output is vulnerable to terms of trade shocks. Moreover, Saudi Arabian terms of trade are driven by output, trade balance, and aggregate demand shocks. To stabilize output and the real exchange rate, Saudi Arabia ought to continue diversifying its production base and aim for a stable nominal oil price. (JEL E32, Q43, C22)
Will Open Supply Lower Retail Gasoline Prices?
Authors: Barron John M. , Taylor Beck A. , Umbeck John R.
Published: December 2003

Retail gasoline lessee‐dealers have lobbied for the right to purchase their gasoline supplies from sources other than the lessor‐refiners with whom they have contracted. This article examines a unique data set of gasoline prices in Los Angeles, along with corresponding market‐ and station‐level characteristics, to gain some insights into whether the proposed “open‐supply” legislation would likely lower the prices charged to consumers. Controlling for market‐ and station‐level characteristics, the authors find that stations with the most alternative sources of gasoline supplies have significantly higher retail prices, casting serious doubt on the claims made by open‐supply proponents. (JEL L0, L1, L4)
New Evidence on Gay and Lesbian Household Incomes
Authors: Carpenter Christopher
Published: December 2003

Using independent data from the Centers for Disease Control, the author tests a key assumption of previous research on gay and lesbian incomes: that same‐sex unmarried partner households are, indeed, gay or lesbian. The author shows that this independent data suffers from less severe underreporting of same‐sex unmarried partner households than the 1990 Decennial Census. Furthermore, individual level information on sexual behavior and family planning is used to show that these households exhibit sexual behavior that is systematically different from married and different‐sex couples and that is consistent with a large body of public health and HIV literature on gay men and lesbians. Finally, the author replicates, confirms, and extends previously published Census‐based results on the household income penalty faced by gay male couples, showing that these results are not an artifact of deficient data. He finds similar results for lesbian couples. (JEL J1, J3)
Tenure Choice with Location Selection: The Case of Hispanic Neighborhoods in Chicago
Authors: Toussaint‐Comeau Maude , Rhine Sherrie L. W.
Published: December 2003

A notable feature of immigration into the United States is the high degree of spatial concentration of different immigrant groups. This article asks the question whether residing in areas with a large proportion of a coethnic group influence the decision to own a home for Hispanics in the Chicago metropolitan area. The results show that Hispanics choose to live in Hispanic enclaves based on relatively homogeneous characteristics, such as recent migration, less English language fluency, and lower income. More years in the United States, higher education attainment, and English language fluency remain strong predictors of homeownership. Individuals are less likely to be homeowners in communities with a larger coethnic concentration, foreign‐born residents, or lower‐income families. (JELC35,J1,R12)
School Finance Litigation, Tax and Expenditure Limitations, and Education Spending
Authors: Blankenau William F. , Skidmore Mark L.
Published: December 2003

Since the early 1970s, litigation in many U.S. states has led to education finance reform. Over the same period, many states have imposed new tax and expenditure limitations (TELs) on local governments. The imposition of a TEL may alter how local and state education expenditures change subsequent to court‐mandated decreases in spending inequality. Similarly, the effectiveness of TELs in limiting local education expenditures may be influenced by reform. To better evaluate the effects of reform and TELs on education spending, this article considers them jointly and finds that reform has a negative effect on local own‐source education expenditures only in the presence of TELs. In the absence of court‐ordered reform, TELs decrease own‐source expenditure, but the effect is less pronounced than when TELs are present with reform. When both are present, state government spending on education is higher. Also TELs and court‐ordered reform independently increase state government spending on education. (JEL H72, I22)
Hypothermic Protection in Rat Focal Ischemia Models: Strain Differences and Relevance to “Reperfusion Injury”
Authors: Ren Yubo , Hashimoto Megumi , Pulsinelli William A. , Nowak Thaddeus S.
Published: December 2003

Hypothermic protection was compared in Long-Evans and spontaneously hypertensive rat (SHR) strains using transient focal ischemia, and in Wistar and SHR strains using permanent focal ischemia. Focal ischemia was produced by distal surgical occlusion of the middle cerebral artery and tandem occlusion of the ipsilateral common carotid artery (MCA/CCAO). Moderate hypothermia of 2 hours' duration was produced by systemic cooling to 32 °C, with further cooling of the brain achieved by reducing to 30°C the temperature of the saline drip superfusing the exposed occlusion site. Infarct volume was determined from serial hematoxylin and eosin-stained frozen sections obtained routinely at 24 hours, or in some cases after 3 days' survival. In the SHR, moderate hypothermia was only effective when initiated before recirculation after a 90-minute occlusion period. In contrast, the same intervention was strikingly effective in the Long-Evans rat even when initiated after as long as 30-minute reperfusion after a 3-hour occlusion. This magnitude and duration of cooling was not protective in permanent MCA/CCAO in the SHR, but such transient hypothermia did effectively reduce infarct volume after permanent occlusions in Wistar rats. These results show striking differences in the temporal window for hypothermic protection among rat focal ischemia models. As expected, “reperfusion injury” in the Long-Evans strain is particularly responsive to delayed cooling. The finding that the SHR can be protected by hypothermia initiated immediately before recirculation suggests a rapidly evolving component of injury occurs subsequent to reperfusion in this model as well. Hypothermic protection after permanent occlusion in Wistar rats identifies a transient, temperature-sensitive phase of infarct evolution that is not evident in the unreperfused SHR. These observations confirm that distinct mechanisms can underlie the temporal progression of injury in rat stroke models, and emphasize the critical importance of considering model and strain differences in extrapolating results of hypothermic protection studies in animals to the design of interventions in clinical stroke.
Protein Kinase C-γ and Calcium/Calmodulin-Dependent Protein Kinase II-α Are Persistently Translocated to Cell Membranes of the Rat Brain during and after Middle Cerebral Artery Occlusion
Authors: Matsumoto Shohei , Shamloo Mehrdad , Matsumoto Eriko , Isshiki Atsushi , Wieloch Tadeusz
Published: December 2003

The levels of protein kinase C-γ (PKC-γ) and the calcium/calmodulin-dependent kinase II-α (CaMKII-α) were measured in crude synaptosomal (P2), particulate (P3), and cytosolic (S3) fractions of the neocortex of rats exposed to 1-hour and 2-hour middle cerebral artery occlusion (MCAO) and 2-hour MCAO followed by 2-hour reperfusion. During MCAO, PKC levels increased in P2 and P3 in the most severe ischemic areas concomitantly with a decrease in S3. In the penumbra, PKCγ decreased in S3 without any significant increases in P2 and P3. Total PKC-γ also decreased in the penumbra but not in the ischemic core, suggesting that the protein is degraded by an energy-dependent mechanism, possibly by the 26S proteasome. The CaMKII-α levels increased in P2 but not P3 during ischemia and reperfusion in all ischemic regions, particularly in the ischemic core. Concomitantly, the levels in S3 decreased by 20% to 40% in the penumbra and by approximately 80% in the ischemic core. There were no changes in the total levels of CaMKII-α during MCAO. The authors conclude that during and after ischemia, PKC and CaMKII-α are translocated to the cell membranes, particularly synaptic membranes, where they may modulate cellular function, such as neurotransmission, and also affect cell survival. Drugs preventing PKC and/or CaMKII-α translocation may prove beneficial against ischemic cell death.
Amelioration of Hippocampal Neuronal Damage after Transient Forebrain Ischemia in Cyclooxygenase-2—Deficient Mice*
Authors: Sasaki Tsutomu , Kitagawa Kazuo , Yamagata Kanato , Takemiya Takako , Tanaka Shigeru , Omura-Matsuoka Emi , Sugiura Shiro , Matsumoto Masayasu , Hori Masatsugu
Published: December 2003

Several studies have suggested that cyclooxygenase-2 (COX-2) plays a role in ischemic neuronal death. Genetic disruption of COX-2 has been shown to reduce susceptibility to focal ischemic injury and N-methyl-D-aspartate-mediated neurotoxicity. The purpose of this study was to examine the effects of COX-2 deficiency on neuronal vulnerability after transient forebrain ischemia. Marked upregulation of COX-2 immunostaining in neurons was observed at the early stage and prominent COX-2 staining persisted in the CA1 medial sector and CA2 sector over 3 days after ischemia. The immunohistologic pattern of COX-2 staining in these sectors gradually condensed to a perinuclear location. The degree of hippocampal neuronal injury produced by global ischemia in COX-2–deficient mice was less than that in wild-type mice, coincident with attenuation of DNA fragmentation in the hippocampus. Also, treatment with a selective COX-2 inhibitor, nimesulide, after ischemia decreased hippocampal neuronal damages. These results of genetic disruption and chemical inhibition of cyclooxygenase-2 show that inhibition of COX-2 ameliorates selective neuronal death after transient forebrain ischemia in mice.
Plate 469. Acanthogilia gloriosa
Authors: Hsu Eric , Hall Tony
Published: December 2003

The distribution, ecology, taxonomy, and cultural requirements of this unusual member of the Polemoniaceae are discussed and a full description of the species is provided; an illustration of Acanthogilia gloriosa (Brandegee) Day & Moran (Polemoniaceae) is also provided.