bluuebunny/crossref_metadata_2025 huggingface dataset:
Hemisphere coupling in Enceladus' asymmetric plasma interaction
Authors: Saur Joachim , Neubauer Fritz M. , Schilling Nico
Published: November 2007

The recently discovered neutral gas plume around the south pole of Enceladus introduces a pronounced north‐south asymmetry in the plasma interaction of Saturn's magnetosphere with Enceladus. In this work we present an analytic model for such an asymmetric interaction for both an Alfvénic and a unipolar inductor far field model including the Hall effect. We find that even though both hemispheres of Enceladus are not directly connected through magnetic field lines, both hemispheres are electromagnetically coupled, that is, the perturbations of the velocity and magnetic fields generated around the south polar plume are mapped in a modified way into the northern hemisphere. This hemisphere coupling creates surface currents on the magnetic flux tube determined by field lines tangent to the body of Enceladus. The surface currents are accompanied by a magnetic field discontinuity across the flux tube on both hemispheres, that is, a discontinuity across the northern and the southern wings. The Cassini spacecraft has not yet crossed this boundary, which we here predict. The diameter and other properties of the discontinuity are diagnostic of plume properties and might be even diagnostic of electrodynamic induction in a potential subsurface ocean on Enceladus. Our model is also applicable to other satellite plasma interactions where similar asymmetries can occur such as Io or extra solar planets.
SM‐protein‐controlled ER‐associated degradation discriminates between different SNAREs
Authors: Braun Sigurd , Jentsch Stefan
Published: November 2007

Endoplasmic reticulum (ER)‐associated degradation (ERAD) is a specialized activity of the ubiquitin–proteasome system that is involved in clearing the ER of aberrant proteins and regulating the levels of specific ER‐resident proteins. Here we show that the yeast ER‐SNARE Ufe1, a syntaxin (Qa‐SNARE) involved in ER membrane fusion and retrograde transport from the Golgi to the ER, is prone to degradation by an ERAD‐like mechanism. Notably, Ufe1 is protected against degradation through binding to Sly1, a known SNARE regulator of the Sec1–Munc18 (SM) protein family. This mechanism is specific for Ufe1, as the stability of another Sly1 partner, the Golgi Qa‐SNARE Sed5, is not influenced by Sly1 interaction. Thus, our findings identify Sly1 as a discriminating regulator of SNARE levels and indicate that Sly1‐controlled ERAD might regulate the balance between different Qa‐SNARE proteins.
Tetratricopeptide repeat proteins Tom70 and Tom71 mediate yeast mitochondrial morphogenesis
Authors: Kondo‐Okamoto Noriko , Shaw Janet M , Okamoto Koji
Published: November 2007

The maintenance of correct mitochondrial shape requires numerous proteins that act on the surface or inside of the organelle. Although the soluble F‐box protein Mfb1 was recently found to associate peripherally with mitochondria and to regulate organelle connectivity in budding yeast, how it localizes to mitochondria is unknown. Here, we show that two tetratricopeptide repeat proteins—the general preprotein import receptor Tom70 (a component of translocase of the outer membrane) and its paralogue Tom71—are required for Mfb1 mitochondrial localization. Mitochondria in cells lacking Tom70 and Tom71 form short tubules and aggregates, aberrant morphologies similar to those observed in the mfb1‐null mutant. In addition, Mfb1 interacts with Tom71 in vivo, and binds to mitochondria through Tom70 in vitro. Our data indicate an unexpected role for Tom70 in recruitment of soluble proteins to the mitochondrial surface, and indicate that Tom71 has a specialized role in Mfb1‐mediated mitochondrial morphogenesis.
Mechanisms and energetics of hydride dissociation reactions on surfaces of plasma-deposited silicon thin films
Authors: Singh Tejinder , Valipa Mayur S. , Mountziaris T. J. , Maroudas Dimitrios
Published: November 2007

We report results from a detailed analysis of the fundamental silicon hydride dissociation processes on silicon surfaces and discuss their implications for the surface chemical composition of plasma-deposited hydrogenated amorphous silicon (a-Si:H) thin films. The analysis is based on a synergistic combination of first-principles density functional theory (DFT) calculations of hydride dissociation on the hydrogen-terminated Si(001)-(2×1) surface and molecular-dynamics (MD) simulations of adsorbed SiH3 radical precursor dissociation on surfaces of MD-grown a-Si:H films. Our DFT calculations reveal that, in the presence of fivefold coordinated surface Si atoms, surface trihydride species dissociate sequentially to form surface dihydrides and surface monohydrides via thermally activated pathways with reaction barriers of 0.40–0.55eV. The presence of dangling bonds (DBs) results in lowering the activation barrier for hydride dissociation to 0.15–0.20eV, but such DB-mediated reactions are infrequent. Our MD simulations on a-Si:H film growth surfaces indicate that surface hydride dissociation reactions are predominantly mediated by fivefold coordinated surface Si atoms, with resulting activation barriers of 0.35–0.50eV. The results are consistent with experimental measurements of a-Si:H film surface composition using in situ attenuated total reflection Fourier transform infrared spectroscopy, which indicate that the a-Si:H surface is predominantly covered with the higher hydrides at low temperatures, while the surface monohydride, SiH(s), becomes increasingly more dominant as the temperature is increased.
Quantifying the complexity of excised larynx vibrations from high-speed imaging using spatiotemporal and nonlinear dynamic analyses
Authors: Zhang Yu , Jiang Jack J. , Tao Chao , Bieging Erik , MacCallum Julia K.
Published: November 2007

In this paper, we investigate the biomechanical applications of spatiotemporal analysis and nonlinear dynamic analysis to quantitatively describe regular and irregular vibrations of twelve excised larynges from high-speed image recordings. Regular vibrations show simple spatial symmetry, temporal periodicity, and discrete frequency spectra, while irregular vibrations show complex spatiotemporal plots, aperiodic time series, and broadband spectra. Furthermore, the global entropy and correlation length from spatiotemporal analysis and the correlation dimension from nonlinear dynamic analysis reveal a statistical difference between regular and irregular vibrations. In comparison with regular vibrations, the global entropy and correlation dimension of irregular vibrations are statistically higher, while the correlation length is significantly lower. These findings show that spatiotemporal analysis and nonlinear dynamic analysis are capable of describing the complex dynamics of vocal fold vibrations from high-speed imaging and may potentially be helpful for understanding disordered behaviors in biomedical laryngeal systems.
Vulnerability to re-entry in simulated two-dimensional cardiac tissue: Effects of electrical restitution and stimulation sequence
Authors: Tran Diana X. , Yang Ming-Jim , Weiss James N. , Garfinkel Alan , Qu Zhilin
Published: November 2007

Ventricular fibrillation is a lethal arrhythmia characterized by multiple wavelets usually starting from a single or figure-of-eight re-entrant circuit. Understanding the factors regulating vulnerability to the re-entry is essential for developing effective therapeutic strategies to prevent ventricular fibrillation. In this study, we investigated how pre-existing tissue heterogeneities and electrical restitution properties affect the initiation of re-entry by premature extrastimuli in two-dimensional cardiac tissue models. We studied two pacing protocols for inducing re-entry following the “sinus” rhythm (S1) beat: (1) a single premature (S2) extrastimulus in heterogeneous tissue; (2) two premature extrastimuli (S2 and S3) in homogeneous tissue. In the first case, the vulnerable window of re-entry is determined by the spatial dimension and extent of the heterogeneity, and is also affected by electrical restitution properties and the location of the premature stimulus. The vulnerable window first increases as the action potential duration (APD) difference between the inside and outside of the heterogeneous region increases, but then decreases as this difference increases further. Steeper APD restitution reduces the vulnerable window of re-entry. In the second case, electrical restitution plays an essential role. When APD restitution is flat, no re-entry can be induced. When APD restitution is steep, re-entry can be induced by an S3 over a range of S1S2 intervals, which is also affected by conduction velocity restitution. When APD restitution is even steeper, the vulnerable window is reduced due to collision of the spiral tips.
Packing structures of single-stranded DNA and double-stranded DNA thiolates on Au(111): A molecular simulation study
Authors: Yao Liqun , Sullivan Jim , Hower Jason , He Yi , Jiang Shaoyi
Published: November 2007

The packing structures of single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) thiolates on implicit gold surfaces were studied in explicit aqueous solutions of 1M NaCl using molecular dynamics simulations. The simulations were based on individual DNA chains placed in hexagonal simulation boxes of different sizes, representing various packing densities. The total potential energy per DNA chain was compared. The optimal packing structures were determined based on the minimal potential energy within the limits of the conditions that were evaluated in this study. The optimal packing density of ssDNA was found to be 0.19 DNA chains/nm2, which is consistent with that determined experimentally. Furthermore, the optimal packing density of dsDNA was shown to be ∼58% of the packing density for ssDNA, indicating that the packing of ssDNA should be ∼58% of its optimal packing in order to achieve the best hybridization.
Simulation of electron distribution features in the ionization process of an electron cyclotron resonance discharge
Authors: Jin Xiaolin , Yang Zhonghai , Huang Tao
Published: November 2007

A theoretical and computational model has been proposed to study the characteristics of electron distribution features in the ionization process of the argon electron cyclotron resonance microwave discharge. A quasi-three-dimensional electromagnetic particle-in-cell plus Monte Carlo collision method is used. The elastic, excitation, ionizing electron-neutral collisions and elastic, charge exchange ion-neutral collisions are taken into account. The detailed information about the distributions of electron and electromagnetic fields are obtained, and the influence of neutral pressures on the electron energy distribution is also involved.
Influence of nonlinear loss competition on pulse compression and nonlinear optics in silicon
Authors: Tien En-Kuang , Qian Feng , Yuksek Nuh S. , Boyraz Ozdal
Published: November 2007

Aggregate nonlinear response of silicon is determined by the competition between the free carrier absorption (FCA) and two-photon absorption (TPA). We show that the front end of optical pulses is always exposed to TPA dominated nonlinear regime, whereas the trailing edge can be seen at FCA dominated regime at high intensities. These two losses can be used for pulse compression if the center of the pulse is in FCA dominated nonlinear regime. To reach this operation regime, energy of 50ps wide pulses has to be larger than 50nJ (40GW∕cm2). Competition phenomenon is observed experimentally in a mode locked laser setup to generate 60ps pulse of 60nJ.
Effects of ultraviolet irradiation on energy band structure and conductivity of polyaniline
Authors: Lin Yow-Jon , Yang Fu-Ming , Lin Chi-Shin
Published: November 2007

The effects of ultraviolet (UV) irradiation on the electrical property of polyaniline (PANI) have been researched in this study. Spectroscopic methods [Raman spectroscopy (532 nm excitation) and x-ray photoelectron spectroscopy] and electrical conductivity measurements were used to characterize the conducting polymer PANI with and without UV irradiation. The authors found that UV irradiation could lead to degenerating electrical conductivity of PANI, resulting from an increase in the surface band bending and a reduction in the work function.
Dynamic control of visible radiation by a liquid crystal filled Fabry-Pérot etalon
Authors: Jewell S. A. , Cornford S. L. , Sambles J. R.
Published: November 2007

A liquid crystal filled Fabry-Pérot etalon has been constructed to control the resonant transmission of electromagnetic radiation over the visible range of the spectrum. This has been achieved through the use of a 1.5μm thick homogeneously aligned liquid crystal layer in the core of a silver-clad etalon structure. Applying an electric field across the core reorientates the liquid crystal director and changes the refractive index for incident light polarized parallel to the rubbing direction. By measuring the transmitted intensity as a function of wavelength for a variety of applied voltages shifts in the positions of the resonant transmission modes of up to 80nm have been observed. In addition, these results have been compared to model data generated using a multilayer optics model to obtain the dispersion of the liquid crystal over the visible range of the electromagnetic spectrum.
A Lorentz force based fusion magnetometer-accelerometer with dual functions for the electronic compass
Authors: Cho Ji-Man , Lee Sang-Yong , Kim Soo-Won , Kim Kyung Soo , An Sengdo
Published: November 2007

The authors present a Lorentz force based fusion magnetometer-accelerometer, which can detect simultaneously both geomagnetic field and acceleration. The sensor is fabricated on a silicon-on-glass wafer and packaged by silicon-gold eutectic bonding. When 1g and 0.35G are applied to the sensor, the fabricated magnetometer-accelerometer has a sensitivity of 153mV∕G in magnetic field sensing and a sensitivity of 400mV∕g in acceleration sensing. The sensor performance is sufficient for resolving approximately 10° in the orientation angle and it can function as an electronic compass in portable navigators that must be small and have low cost, and low power.
Microstructure and frequency dependent electrical properties of Mn-substituted BiFeO3 thin films
Authors: Singh S. K. , Ishiwara H. , Sato K. , Maruyama K.
Published: November 2007

Mn-substituted (0–10at.%) BiFeO3 (BFO) thin films were fabricated by chemical solution deposition on Pt∕Ti∕SiO2∕Si substrate. X-ray diffraction analysis revealed that no secondary phase appeared even if Fe atoms were substituted with Mn atoms up to 10at.%. However, in the 10at.% Mn-substituted BFO film, the lattice parameters decreased by approximately 0.6%. Substitution of small amount of Mn atoms such as 3–5at.% in BFO films was effective in reducing the leakage current density at a high electric field. The P-E (polarization versus electric field) hysteresis loops were measured by changing frequencies of triangular voltage pulses from 1to100kHz. In Mn-substituted BFO films, frequency dependences of the remanent polarization were not pronounced in the range from 10to100kHz and these measurements showed that the remanent polarization increased with increase of the Mn concentration.
Quantitative digital detection of magnetic beads using pseudo-spin-valve rings for multiplexed bioassays
Authors: Llandro J. , Hayward T. J. , Morecroft D. , Bland J. A. C. , Castaño F. J. , Colin I. A. , Ross C. A.
Published: November 2007

We present a magnetic multiplexed assay technology which encodes the identities of target biomolecules according to the moment of magnetic beads to which they are attached. An active digital technique based on a microfabricated magnetoresistive ring-shaped sensor is demonstrated, which can distinguish the magnetic moments of micron-sized superparamagnetic beads. We propose that this development is key to combining nonvolatile magnetic labeling with biochemical libraries for high-throughput bioassays and rapid multiplexed detection.
Detection of the optical polarization angle with bandpass characteristics based on M-plane GaN photodetectors
Authors: Rivera C. , Muñoz E. , Brandt O. , Grahn H. T.
Published: November 2007

The authors present a photodetection configuration which allows for the determination of the optical in-plane polarization angle of the incident light beam with respect to a reference axis. The implementation for the ultraviolet spectral range is based on the intrinsic properties of M-plane GaN-based photodetectors on LiAlO2 substrates. This configuration can provide an infinite rejection ratio between the photodetector signal for light polarized perpendicular and parallel to the direction of maximum sensitivity. In addition, this configuration exhibits a bandpass response independent of the polarization state of the incident light beam with a bandwidth below 10nm for M-plane GaN-based photodetectors.
InN-based anion selective sensors in aqueous solutions
Authors: Lu Yen-Sheng , Huang Chi-Cheng , Yeh J. Andrew , Chen Chi-Fan , Gwo Shangjr
Published: November 2007

We demonstrate that indium nitride (InN) can be used as ion selective electrode (ISE) for anion concentration measurements. The InN ISE reveals remarkable selectivity, response time, signal stability, and repeatability for chlorine and hydroxyl ions. The selective interaction of Lewis bases in solutions with the N-polarity InN epitaxial layer grown on silicon is confirmed by potentiometric responses. The Helmholtz potential of the InN ISE, generated at the InN/solution interface, satisfies the Nernst equation. The observation of anion attraction to the InN surface further demonstrates the existence of donor-type surface states on InN.
Minute pinning and doping additions for strong, 20K, in-field critical current improvement in MgB2
Authors: Mikheenko P. , Chen S. K. , MacManus-Driscoll J. L.
Published: November 2007

Minute additions of a combination of Dy2O3 and B4C have been used to enhance both pinning and upper critical field in MgB2. A delicate balance of Dy2O3 and B4C additions is required to improve properties. The Dy2O3 nanoparticles react with B to form 10–15nm DyB4 nanoparticles, while B4C supplies carbon into the MgB2 crystal lattice and increases the upper critical field. The optimum level of Dy2O3 and B4C additions is ∼0.5wt% of Dy2O3 and 0.04wt% of B4C, yielding a Jc (20K) of 105Acm−2 at 2.7T.
Giant thermoelectric effect in graphene
Authors: Dragoman D. , Dragoman M.
Published: November 2007

The paper predicts a giant thermoelectric coefficient in a nanostructure consisting of metallic electrodes periodically patterned over graphene, which is deposited on a silicon dioxide substrate. The Seebeck coefficient in this device attains 30mV∕K, this value being among the largest reported ever. The calculations are based on a transfer matrix approach that takes a particular form for graphene-based devices. The results are important for future nanogenerators with applications in the area of sensors, energy harvesting, and scavenging.
The magnetic-field-induced transition from an expanding plasma to a double layer containing expanding plasma
Authors: Charles C. , Boswell R. W.
Published: November 2007

The magnetic-field-induced transition from a simple expansion to a double layer is experimentally investigated in an argon low pressure radio frequency helicon source plasma. When the magnetic field is increased from 30to140G in the plasma source, an abrupt increase in the plasma density and upstream potential is measured at 50G. In the downstream plasma, the plasma density and potential show a small decrease with increasing magnetic field and no abrupt change. When the upstream jump is measured, simultaneous measurements in the downstream plasma show an ion beam characteristic of a double layer near the source exit.
Imaging spatial distributions of laser-induced charge and spin in GaAs∕AlGaAs two-dimensional electron gas by pump-probe second harmonic generation
Authors: Han Yibo , Xiao Si , Zhao Hongming , Gao Hanchao , Xiong G. G. , Wang Q. Q.
Published: November 2007

We report the spatial intensity distributions of the laser-induced charge and spin polarizations in GaAs∕AlGaAs two-dimensional electron gas (2DEG) detected by using second harmonic generation (SHG) imaging technique. The spin polarized electrons in the 2DEG are pumped by a single linear polarized laser beam and probed by another beam which produces reflective SHG. By comparing the images of SHG probed with left- and right-circular polarized laser beams, the spatial distributions of the effective charge and spin polarizations in the 2DEG sample are mapped out.
Resistive memory switching in epitaxially grown NiO
Authors: Lee S. R. , Char K. , Kim D. C. , Jung R. , Seo S. , Li X. S. , Park G.-S. , Yoo I. K.
Published: November 2007

Epitaxial NiO films have been fabricated on SrRuO3 films prepared on SrTiO3 single-crystal substrates. The x-ray diffraction spectra and transmission electron microscopy confirm the epitaxial growth of NiO with atomically flat surfaces on the SRO electrode. The I-V measurements of epitaxial NiO show the resistive memory switching behavior with a change in the polarity of the voltage bias, in contrast with the switching behavior of polycrystalline NiO by a single polarity. The I-V characteristics of epitaxial NiO prepared under various synthesis conditions and electrodes are presented, which suggests an important role of interfaces between NiO and electrodes on the resistive switching behavior.
Direct observation of quantized interlayer vortex flow in a high-Tc La1.87Sr0.13CuO4 single crystal
Authors: Iguchi I. , Arisawa S. , Yun K.-S. , Hatano T. , Uchiyama T. , Tanaka I.
Published: November 2007

We have observed directly the magnetic images of the dynamic motion of quantized interlayer vortices induced by the Lorentz force in an anisotropic high-Tc La1.87Sr0.13CuO4 single crystal. A scanning superconducting quantum interface device microscope is used for this study and it is found that three modes of flux motion exist depending on the transport current. By increasing the sample current‖c axis, a transition from the creeplike behavior to a steady flow of vortices was observed. Even higher current induced a continuous expansion of vortex-flow area depending on the inhomogeneity of the pinning force in a crystal.
Radical-source molecular beam epitaxy of ZnMgO and ZnCdO alloys on ZnO substrates
Authors: Sadofev S. , Schäfer P. , Fan Y.-H. , Blumstengel S. , Henneberger F. , Schulz D. , Klimm D.
Published: November 2007

We report on a dramatic improvement of the crystalline quality of ZnMgO and ZnCdO epilayers using Bridgman-grown ZnO substrates. ZnMgO alloys grow pseudomorphically over several 100nm and the (0002) ω-rocking curve width is as low as 19arcsec. Strain inhomogeneities in low-temperature grown ZnCdO are significantly reduced and the rocking width is lowered down to 45arcsec. Despite the high crystalline perfection, the optical properties of the films are mainly determined by their ternary character.
The mechanism for polarity inversion of GaN via a thin AlN layer: Direct experimental evidence
Authors: Liu Fude , Collazo Ramon , Mita Seiji , Sitar Zlatko , Duscher Gerd , Pennycook Stephen J.
Published: November 2007

Lateral-polarity heterostructures of GaN on c sapphire were prepared by deposition and patterning of a thin low-temperature AlN nucleation layer. Adjacent macroscopic domains were found to have opposite polarity; domains grown on the AlN nucleation layer were Ga polar while those grown on the nitrided sapphire were N polar, as confirmed by convergent-beam electron diffraction and Z-contrast images. We directly determined the atomic interface structure between the AlN and c sapphire with an aberration-corrected scanning transmission electron microscope at ∼1.0Å resolution. This is the direct experimental evidence for the origin of the polarity control in III nitrides. This understanding is an important step toward manipulating polarity in these semiconductors.
Free-running InGaAs∕InP avalanche photodiode with active quenching for single photon counting at telecom wavelengths
Authors: Thew R. T. , Stucki D. , Gautier J.-D. , Zbinden H. , Rochas A.
Published: November 2007

We present an InGaAs∕InP avalanche photodiode with an active quenching circuit on an application specific integrated circuit (ASIC) that is capable of operating in both gated and free-running modes. The 1.6mm2 ASIC chip is fabricated using complementary metal oxide semiconductor technology guaranteeing long-term stability, reliability, and compactness. In the free-running mode, we find a single photon detection efficiency of 10% with <2kHz of noise.
Structural investigation of nitrided c-sapphire substrate by grazing incidence x-ray diffraction and transmission electron microscopy
Authors: Lee Hyo-Jong , Ha Jun-Seok , Lee S. W. , Lee H. J. , Goto H. , Lee S. H. , Cho M. W. , Yao T. , Minegishi T. , Hanada T. , Hong Soon-Ku , Sakata Osami , Lee Jae Wook , Lee Jeong Yong
Published: November 2007

A grazing incidence x-ray diffraction with a synchrotron radiation and a cross-sectional high-resolution transmission electron microscopy were performed on the sapphire surface nitrided at 1080°C for 30min. The thickness of the nitrided layer was about 2nm. It was found out that the wurtzite, zinc-blende, and 30° rotated zinc-blende aluminum nitrides were formed on the sapphire surface. The 30° rotated zb-AlN formed the incoherent interface and has higher activation energy of formation, while the nonrotated zb-AlN formed the coherent interface.
Growth of single crystalline GaN on silver mirrors
Authors: Inoue S. , Okamoto K. , Nakano T. , Ohta J. , Fujioka H.
Published: November 2007

GaN films have been grown on highly thermally conducting Ag(111) substrates by using pulsed laser deposition. GaN(0001) grows epitaxially on Ag(111) with an in-plane epitaxial relationship of GaN[112¯0]‖Ag[11¯0] when low temperature AlN buffer layers are used. The heterointerfaces in the AlN∕Ag structure are atomically abrupt, and that the abruptness remains unchanged during annealing up to 700°C for the GaN growth. Neither 30° rotational domains nor cubic phase domains exist in the GaN films. It has been also confirmed that the GaN films grown on the Ag substrate exhibit strong near band edge photoluminescence emission at 3.51eV. These results indicate that the epitaxial growth of GaN on mirror-polished single crystalline Ag substrates possibly improve the power limits and the light extraction efficiency of future light-emitting devices.
A high-brightness circular charged-particle beam system
Authors: Bemis T. , Bhatt R. , Chen C. , Zhou J.
Published: November 2007

A method is presented for the design of a high-brightness nonrelativistic circular beam system including a charged-particle emitting diode, a diode aperture, a circular beam tunnel, and a focusing magnetic field that matches the beam from the emitter to the beam tunnel. The applied magnetic field is determined by balancing the forces throughout the gun and transport sections of the beam system. The method is validated by three-dimensional simulations.
Fire regime (recency, interval and season) changes the composition of spinifex (Triodia spp.)-dominated desert dunes
Authors: Wright Boyd R. , Clarke Peter J.
Published: November 2007

Between 2000 and 2002, central Australia experienced the largest fire season in three decades when ~500 000 km2 burned. The effects of these and preceding wildfires in the 1980s on spinifex (Triodia spp.) sand-ridge plant communities were examined at 38 sites in central Australia. We used both multivariate and univariate techniques to assess floristic differences among sites of contrasting time-since-fire, fire season and fire interval. Time-since-fire had a consistent floristic influence across the landscape, with increased abundances of ephemeral grasses and forbs and Triodia seedlings, and species richness soon after fire but decreasing long after fire. Fire season had little effect on most functional groups of plants, although seedlings of woody species were significantly more abundant following summer than winter fires. Likewise, recent short fire intervals appeared to have little impact on the population dynamics of most functional groups, although some transient effects were observed on abundances of ephemeral forbs, Triodia seedlings and herbaceous clonal species. Long-term woody species abundances appeared to be affected by short fire intervals in the 1980s when repeated fires seemed to stimulate recruitment of some resprouting species. The present study highlighted the relative stability of spinifex vegetation types in the face of landscape-scale pyric perturbation, but emphasised that localised shifts in the composition and structure of the plant community may occur under certain fire regimes.
Phytotoxic response and yield of chickpea (Cicer arietinum) genotypes with pre-emergence application of isoxaflutole
Authors: Datta A. , Sindel B. M. , Jessop R. S. , Kristiansen P. , Felton W. L.
Published: November 2007

Balance® (75% a.i. isoxaflutole) at 100 g/ha is registered in Australia for the control of several broadleaf weeds in chickpea. Polyhouse and field experiments were carried out to examine the tolerance of chickpea genotypes to isoxaflutole. Seven rates of isoxaflutole [0, 18.75, 37.5, 75 (recommended rate), 150, 300 and 600 g a.i./ha] were applied to 20 genotypes in the first polyhouse experiment while in the second experiment, 16 genotypes were tested. In the field, six genotypes were treated with five herbicide rates (0, 37.5, 75, 150 and 300 g a.i./ha). There was a strong dose response in the polyhouse experiments in visual injury ratings, plant height, and shoot and root dry weight. In general, there was less herbicide injury to the kabuli genotypes than in the desi chickpea genotypes. Chickpea genotypes Yorker, Howzat, Amethyst, Gully, 91025-3021, Jimbour, S 95425 and FLIP 94-92C exhibited higher overall mean injury rating in experiment 1. Among these genotypes, shoot dry matter was reduced significantly in Amethyst, Jimbour, 91025-3021 and S 95425. Root dry matter in Amethyst, Jimbour, Yorker, 91025-3021 and S 95425 was also reduced significantly. Height was reduced significantly in all of the above eight genotypes. Although there was less overall injury level in the second polyhouse experiment, which was at lower temperatures, Howzat, Yorker, 91025-3021, FLIP 94-92C and S 95425 again recorded high overall mean injury ratings and should be regarded as more susceptible to isoxaflutole than the other strains. In comparison, 97039-1275 and Kyabra recorded very minor injury symptoms in all the experiments and can be regarded as the most tolerant. The herbicide injury to the genotypes in the field was less than in the polyhouse although Yorker and 91025-3021 showed injury symptoms at early stages of growth. The injury symptoms were temporary and did not produce significant effects on the overall crop growth and yield. It is suggested that plant breeding programs take into account the relative susceptibility of new chickpea genotypes to isoxaflutole.
What is limiting canola yield in southern New South Wales? A diagnosis of causal factors
Authors: Lisson Shaun N. , Kirkegaard John A. , Robertson Michael J. , Zwart Alec
Published: November 2007

During the 1990s there was considerable evidence from grower surveys and other regional statistics to suggest that canola (Brassica napus) yields were declining in the medium and high rainfall areas of southern New South Wales (NSW). A paddock survey was conducted across three regions of southern NSW over three consecutive seasons (2003–05) to explore the importance of disease and other possible causes of low productivity. Under-performing paddocks were identified by comparing measured paddock yields with simulated potential yields. The causes of the resultant yield gaps were identified by analysis of the survey results with growers and consultants and from insights provided by the simulation analysis. Seasonal water supply and emergence date accounted for around 70% of the variation in yield across the survey, although no dependence on these variables was evident in 2005 as a result of high spring rainfall. A majority (95) of the 132 paddocks surveyed yielded to within 20% of the simulated potential yield. Disease, while significant in some paddocks, was limited by the dry seasons, there was no evidence for widespread micronutrient deficiencies and most crops were adequately supplied with nitrogen. There was no single cause of under-performance and the impact of those causes varied across regions and seasons. Subsoil constraints (seven paddocks) and late season water stress (six paddocks) were the most common factors associated with under-performance, while five paddocks had inexplicable yield gaps. Restrictions to taproot growth were widespread, especially in the southern region where around 60% of paddocks had significantly restricted taproots in all seasons (>3 on a 0–5 scale). Survey paddocks in which significant root restriction was found were between 10 and 50% below potential yield. Subsequent soil profile analysis identified a range of possible subsoil constraints including high soil strength, sodic or saline subsoils or subsurface acidity and further research is warranted to determine their impact on canola productivity in the region.
Acoustically detectable cellular-level lung injury induced by fluid mechanical stresses in microfluidic airway systems
Authors: Huh Dongeun , Fujioka Hideki , Tung Yi-Chung , Futai Nobuyuki , Paine Robert , Grotberg James B. , Takayama Shuichi
Published: November 2007

We describe a microfabricated airway system integrated with computerized air–liquid two-phase microfluidics that enables on-chip engineering of human airway epithelia and precise reproduction of physiologic or pathologic liquid plug flows found in the respiratory system. Using this device, we demonstrate cellular-level lung injury under flow conditions that cause symptoms characteristic of a wide range of pulmonary diseases. Specifically, propagation and rupture of liquid plugs that simulate surfactant-deficient reopening of closed airways lead to significant injury of small airway epithelial cells by generating deleterious fluid mechanical stresses. We also show that the explosive pressure waves produced by plug rupture enable detection of the mechanical cellular injury as crackling sounds.
IL-1 receptor accessory protein is essential for IL-33-induced activation of T lymphocytes and mast cells
Authors: Ali Shafaqat , Huber Michael , Kollewe Christian , Bischoff Stephan C. , Falk Werner , Martin Michael U.
Published: November 2007

Lack of the IL-1 receptor accessory protein (IL-1RAcP) abrogates responses to IL-33 and IL-1 in the mouse thymoma clone EL-4 D6/76 cells. Reconstitution with full-length IL-1RAcP is sufficient to restore responsiveness to IL-33 and IL-1. IL-33 activates IL-1 receptor-associated kinase-1, cJun-N-terminal kinase, and the NF-κB pathway in an IL-1RAcP-dependent manner and results in IL-2 release. IL-33 is able to induce the release of proinflammatory cytokines in bone marrow-derived (BMD) mast cells, indicating that IL-33 may have a proinflammatory potential like its relatives IL-1 and IL-18, in addition to its Th2-skewing properties in the adaptive response described previously. Blocking of murine IL-1RAcP with the neutralizing antibody 4C5 inhibits response of mouse thymoma cells and BMD mast cells to IL-33. The interaction of either membrane-bound or soluble forms of IL-1RAcP and IL-33Rα-chain depends on the presence of IL-33, as demonstrated by coimmunoprecipitation assays. These data demonstrate that IL-1RAcP is indispensable for IL-33 signaling. Furthermore, they suggest that IL-1RAcP is used by more than one α-chain of the IL-1 receptor family and thus may resemble a common β-chain of that family.
An
Arabidopsis thaliana
high-affinity molybdate transporter required for efficient uptake of molybdate from soil
Authors: Tomatsu Hajime , Takano Junpei , Takahashi Hideki , Watanabe-Takahashi Akiko , Shibagaki Nakako , Fujiwara Toru
Published: November 2007

Molybdenum (Mo) is a trace element essential for living organisms, however no molybdate transporter has been identified in eukaryotes. Here, we report the identification of a molybdate transporter, MOT1, from
Arabidopsis thaliana. MOT1
is expressed in both roots and shoots, and the MOT1 protein is localized, in part, to plasma membranes and to vesicles. MOT1 is required for efficient uptake and translocation of molybdate and for normal growth under conditions of limited molybdate supply. Kinetics studies in yeast revealed that the
K
m
value of MOT1 for molybdate is ≈20 nM. Furthermore, Mo uptake by MOT1 in yeast was not affected by coexistent sulfate, and MOT1 did not complement a sulfate transporter-deficient yeast mutant strain. These data confirmed that MOT1 is specific for molybdate and that the high affinity of MOT1 allows plants to obtain scarce Mo from soil.
Selective changes of resting-state networks in individuals at risk for Alzheimer's disease
Authors: Sorg Christian , Riedl Valentin , Mühlau Mark , Calhoun Vince D. , Eichele Tom , Läer Leonhard , Drzezga Alexander , Förstl Hans , Kurz Alexander , Zimmer Claus , Wohlschläger Afra M.
Published: November 2007

Alzheimer's disease (AD) is a neurodegenerative disorder that prominently affects cerebral connectivity. Assessing the functional connectivity at rest, recent functional MRI (fMRI) studies reported on the existence of resting-state networks (RSNs). RSNs are characterized by spatially coherent, spontaneous fluctuations in the blood oxygen level-dependent signal and are made up of regional patterns commonly involved in functions such as sensory, attention, or default mode processing. In AD, the default mode network (DMN) is affected by reduced functional connectivity and atrophy. In this work, we analyzed functional and structural MRI data from healthy elderly (
n
= 16) and patients with amnestic mild cognitive impairment (aMCI) (
n
= 24), a syndrome of high risk for developing AD. Two questions were addressed: (
i
) Are any RSNs altered in aMCI? (
ii
) Do changes in functional connectivity relate to possible structural changes? Independent component analysis of resting-state fMRI data identified eight spatially consistent RSNs. Only selected areas of the DMN and the executive attention network demonstrated reduced network-related activity in the patient group. Voxel-based morphometry revealed atrophy in both medial temporal lobes (MTL) of the patients. The functional connectivity between both hippocampi in the MTLs and the posterior cingulate of the DMN was present in healthy controls but absent in patients. We conclude that in individuals at risk for AD, a specific subset of RSNs is altered, likely representing effects of ongoing early neurodegeneration. We interpret our finding as a proof of principle, demonstrating that functional brain disorders can be characterized by functional-disconnectivity profiles of RSNs.
Identification of the β
TP
site in the x-ray structure of F
1
-ATPase as the high-affinity catalytic site
Authors: Mao Hui Z. , Weber Joachim
Published: November 2007

ATP synthase uses a unique rotary mechanism to couple ATP synthesis and hydrolysis to transmembrane proton translocation. The F
1
subcomplex has three catalytic nucleotide binding sites, one on each β subunit, with widely differing affinities for MgATP or MgADP. During rotational catalysis, the sites switch their affinities. The affinity of each site is determined by the position of the central γ subunit. The site with the highest nucleotide binding affinity is catalytically active. From the available x-ray structures, it is not possible to discern the high-affinity site. Using fluorescence resonance energy transfer between tryptophan residues engineered into γ and trinitrophenyl nucleotide analogs on the catalytic sites, we were able to determine that the high-affinity site is close to the C-terminal helix of γ, but at considerable distance from its N terminus. Thus, the β
TP
site in the x-ray structure [Abrahams JP, Leslie AGW, Lutter R, Walker JE (1994)
Nature
370:621–628] is the high-affinity site, in agreement with the prediction of Yang
et al.
[Yang W, Gao YQ, Cui Q, Ma J, Karplus M (2003)
Proc Natl Acad Sci USA
100:874–879]. Taking into account the known direction of rotation, the findings establish the sequence of affinities through which each catalytic site cycles during MgATP hydrolysis as low → high → medium → low.
The simplicity of politicians' personalities across political context: An anomalous replication
Authors: Caprara Gian Vittorio , Barbaranelli Claudio , Fraley R. Chris , Vecchione Michele
Published: November 2007

Modern politics is becoming increasingly personalized. The personal qualities of political candidates, in fact, account for a considerable amount of the variance in the candidate preference of voters, often more than the political issues in their electoral programs. Despite the emphasis that both the media and campaign leaders place on the ways in which the personalities of politicians are portrayed, people tend to view the personalities of politicians in remarkably simple ways. Here we show that, although people tend to use five personality dimensions to characterize their own personalities, they rely upon only two dimensions to characterize the personalities of politicians. This finding holds across countries (i.e., Italy and the US), and across political figures (i.e., Prodi and Berlusconi in Italy, and Bush and Kerry in the US). The two factors obtained from evaluations of Prodi, Berlusconi, and Kerry were respectively a blend of Energy/Extraversion and Openness and a blend of Friendliness, Conscientiousness, and Emotional Stability. The two factors obtained from evaluations of the US president, though, were respectively a blend of Openness, Conscientiousness, and Friendliness, and a blend of Energy/Extraversion, Emotional Stability, and Friendliness. Thus, the present study is novel in suggesting that while the personalities of politicians may be reduced by voters, they are not always reduced to the same basic factors. Alternative explanations of this “simplification effect” are discussed.
At the doorstep to employment: Discrimination against immigrants as a function of applicant ethnicity, job type, and raters' prejudice
Authors: Krings Franciska , Olivares José
Published: November 2007

This study examined the impact of applicant ethnicity, job type, and prejudice on evaluation biases and intentions to interview in an experimental simulation. We suggest that bias and discrimination are more likely when foreign applicants who belong to disliked ethnic groups apply for jobs that require high interpersonal skills, and when raters are prejudiced against immigrants. Subjects were Swiss university students who evaluated Swiss, Spanish, and Kosovo Albanian fictitious applicants. Foreign applicants were second‐generation immigrants, i.e., Swiss‐born descendants of immigrants. Thus, all applicants had similar schooling and language proficiencies but differed with respect to ethnicity. As predicted, discrimination was only observed for members of the disliked ethnic group (Kosovo Albanian) and not for members of the well‐accepted group (Spanish). Moreover, this discrimination was only apparent when applying for a job requiring high interpersonal skills and not when applying for a job requiring high technical skills. Symbolic prejudice towards second‐generation immigrants interacted with applicant ethnicity and job type to affect evaluations of foreign applicants: Persons high in symbolic prejudice devalued foreign applicants belonging to the disliked group but only when applying for a job requiring high interpersonal skills. Overt prejudice was unrelated to evaluations and intentions to interview. These results suggest that discrimination against immigrants is highly specific, targeting only members of certain ethnic groups who apply for certain types of jobs. Moreover, evaluation biases may be more apparent in raters who are prejudiced. Thus, our results support the notion that discrimination for employment results from a complex interaction between characteristics of the applicant, the job, and the rater.
Communitarian Neighborhoods and Religious Minorities in Iran: A Comparative Analysis
Authors: Vivier-Muresan Anne-Sophie
Published: November 2007

This paper analyzes the urban insertion of some Iranian religious minorities, focusing on three communities, all of which lived in separated neighborhoods: Armenians of Isfahan, Jews of Shiraz, and Zoroastrians of Yazd. After a discussion on the link between non-Muslims' spatial and social isolation and Iranian culture and Shiism, the paper goes on to describe the organization of these neighborhoods during the recent centuries and the recent—and contrastive—evolutions of two of them: while Zoroastrians view their quarter like a humiliating ghetto, of which they wish to go out, Armenians are proud of it, and try up till now to jealously preserve their isolation.
Turning Outwards or Turning Inwards? The Russian Orthodox Church Challenged by Fundamentalism
Authors: Walters Philip
Published: November 2007

The 1997 Russian law on religion recognizes Orthodoxy, Islam, Judaism, and Buddhism as the “traditional religions” of Russia. These religions see themselves as having an important role to play in achieving social stability, and particularly in overcoming religious “extremism” and the perceived threat it poses to society. “Traditional'” religions stand shoulder to shoulder, explaining that the values they champion tend towards the creation and preservation of peace and reconciliation in society, and that, moreover, these are shared values, common to all “traditional'‘ religions. Indeed, the primary criterion for identifying a “traditional'” religion in Russia today may be that it is “noncompetitive” with other religions. The Moscow Patriarchate rejects the idea, for example, that Orthodox Christians should proselytize among Muslims. The fact that each religion sees itself as having possession of the “truth” does not endanger the cooperation, harmony and mutual respect among the traditional religions in Russia at the level of official and institutional interaction. Regarding the controversy over the school textbook, Foundations of Orthodox Culture, which human rights activists accused of constituting pro-Orthodox propaganda, an Orthodox priest and a Muslim chief mufti filed a joint claim against those who initiated the case, and a Protestant leader came out in support of the use of the textbook in the public schools.
The Landscape of Interfaith Intolerance in Post-Atheist Russia*
Authors: Karpov Vyacheslav , Lisovskaya Elena
Published: November 2007

The officially atheist Soviet Union did not tolerate any open manifestations of faith except for the rare ones it overtly allowed and covertly controlled. Since all religions were almost entirely suppressed from above, there were no visible manifestations of inter-religious intolerance “from below,” i.e. among the adherents of different faiths. Yet our paper shows that in less than two decades after the demise of the Soviet state and its official atheism, there emerged in Russia an entirely new landscape of widespread and strong interfaith intolerance from below. We describe that landscape using the data from our representative national survey conducted in Russia in 2005.
Political Order, Identity, and Security in Multinational, Multi-Religious Russia
Authors: Warhola James W. , Lehning Alex
Published: November 2007

The basis of a civil nation is common goals, common values, trust in the government, and the understanding that the government serves us. The main task of the people [now] is to avoid military service, taxes, and the authorities in general. Under such conditions, it is impossible to form a civil political nation.