bluuebunny/crossref_metadata_2025 huggingface dataset:
Cutoff effects of electron velocity distribution to the properties of plasma parameters near the plasma-sheath boundary
Authors: Jelić N.
Published: November 2011

The plasma properties under high thermodynamic non-equilibrium condition, established due to the presence of electrically biased electrode, are investigated. Assumption of electron cut-off velocity distribution function (VDF), as done by Andrews and Varey in their investigations of the sheath region [J. Phys. A 3, 413 (1970)], has been extended here to both plasma and sheath regions. Analytic expressions for the moments of electron VDF, as well as for the electron screening temperature function dependence on the plasma-sheath local potential are derived. In deriving the ion velocity distribution the “standard” assumption of strict plasma quasineutrality, or equivalently vanishing of the plasma Debye length, is employed, whereas the ions are assumed to be generated at rest over the plasma region. However, unlike the standard approach of solving the plasma equation, where pure Boltzmann electron density profile is used, here we employ modified Boltzmann’s electron density profile, due to cutoff effect of the electron velocity distribution. It is shown that under these conditions the quasineutrality equation solution is characterised by the electric field singularity for any negative value of the electrode bias potential as measured with respect to the plasma potential. The point of singularity i.e., the plasma length and its dependence on the electrode bias and sheath potential is established for the particular case of ionization profile mechanism proportional to the local electron density. Relevant parameters for the kinetic Bohm criterion are explicitly calculated for both ions and electrons, for arbitrary electrode bias.
On kinetic description of electromagnetic processes in a quantum plasma
Authors: Tyshetskiy Yu. , Vladimirov S. V. , Kompaneets R.
Published: November 2011

A nonlinear kinetic equation for nonrelativistic quantum plasma with electromagnetic interaction of particles is obtained in the Hartree’s mean-field approximation. It is cast in a convenient form of Vlasov-Boltzmann-type equation with “quantum interference integral”, which allows for relatively straightforward modification of existing classical Vlasov codes to incorporate quantum effects (quantum statistics and quantum interference of overlapping particles wave functions), without changing the bulk of the codes. Such modification (upgrade) of existing Vlasov codes may provide a direct and effective path to numerical simulations of nonlinear electrostatic and electromagnetic phenomena in quantum plasmas, especially of processes where kinetic effects are important (e.g., modulational interactions and stimulated scattering phenomena involving plasma modes at short wavelengths or high-order kinetic modes, dynamical screening and interaction of charges in quantum plasma, etc.) Moreover, numerical approaches involving such modified Vlasov codes would provide a useful basis for theoretical analyses of quantum plasmas, as quantum and classical effects can be easily separated there.
Refinement of the theory for extracting cell dielectric properties from dielectrophoresis and electrorotation experiments
Authors: Lei U. , Sun Pei-Hou , Pethig Ronald
Published: November 2011

A modified theory is proposed for extracting cell dielectric properties from the peak frequency measurement of electrorotation (ER) and the crossover frequency measurement of dielectrophoresis (DEP). Current theory in the literature is based on the low frequency (DC) approximations for the equivalent cell permittivity and conductivity, which are valid when the measurements are performed in a medium with conductivity less than 1 mS/m. The present theory extracts the cell properties through optimizing an expression for the medium conductivity in terms of the peak ER, or DEP crossover, frequency according to its definition using full expressions of equivalent cell permittivity and conductivity. Various levels of approximation of the theory are proposed and discussed through a scaling analysis. The present theory can extract both membrane and interior properties from the low and the high peak ER, or DEP crossover, frequencies for any medium conductivity provided the peak ER, or DEP crossover, frequency exists. It can be reduced to the linear theory for the low peak ER and DEP crossover frequencies in the literature when the medium conductivity is less than 10 mS/m. However, we can determine the membrane capacitance and conductance via the slope and intercept, respectively, of the straight line fitting of the ER peak and DEP frequency against medium conductivity data according to the linear theory only when the intercept dominates the experimental uncertainty, which occurs when the medium conductivity is less than 1 mS/m in practice.
A distance-dependent parameterization of the extended Hubbard model for conjugated and aromatic hydrocarbons derived from stretched ethene
Authors: Schmalz Thomas G. , Serrano-Andrés Luis , Sauri Vicenta , Merchán Manuela , Oliva Josep M.
Published: November 2011

The Hubbard model, which is widely used in physics but is mostly unfamiliar to chemists, provides an attractive yet simple model for chemistry beyond the self consistent field molecular orbital approximation. The Hubbard model adds an effective electron-electron repulsion when two electrons occupy the same atomic orbital to the familiar Hückel Hamiltonian. Thus it breaks the degeneracy between excited singlet and triplet states and allows an explicit treatment of electron correlation. We show how to evaluate the parameters of the model from high-level ab initio calculations on two-atom fragments and then to transfer the parameters to large molecules and polymers where accurate ab initio calculations are difficult or impossible. The recently developed MS-RASPT2 method is used to generate accurate potential energy curves for ethene as a function of carbon-carbon bond length, which are used to parameterize the model for conjugated hydrocarbons. Test applications to several conjugated/aromatic molecules show that even though the model is very simple, it is capable of reasonably accurate predictions for bond lengths, and predicts molecular excitation energies in reasonable agreement with those from the MS-RASPT2 method.
Effect of molecular weight on the efficiency of poly(N-vinylcarbazole)-based polymer light-emitting diodes
Authors: Cai Min , Xiao Teng , Chen Ying , Hellerich Emily , Liu Rui , Shinar Ruth , Shinar Joseph
Published: November 2011

Polymer light-emitting diodes based on poly(N-vinylcarbazole) (PVK) with molecular weights MW of 1.1 × 106 and ∼7.5 × 104 are compared. For devices without an electron transport layer (ETL), the high MW PVK yields higher external quantum efficiency (0.67% vs 0.18%), but for devices with an ETL, the low MW PVK yields higher efficiency (1.13% vs 0.83%). This intriguing difference is believed to result from higher energetic disorder in the high MW polymer and different recombination zone-quenching metal electrode distances, in agreement with Konezny et al. [Appl. Phys. Lett. 97, 143305 (2010)].
Coupling modes of three filaments in side-by-side arrangement
Authors: Tian Fang-Bao , Luo Haoxiang , Zhu Luoding , Lu Xi-Yun
Published: November 2011

A viscous flow past three filaments in side-by-side arrangement is studied by a numerical simulation and is accompanied by a previously established linear stability analysis. Other than the coupling modes reported previously, which include the in-phase mode, symmetrical mode, and out-of-phase mode, three additional modes are identified in the nonlinear regime by systematically varying the separation distance between the filaments. These modes are the half-frequency mode, irrational-frequency mode, and erratic flapping state. The dynamic characteristics of each mode at the saturated state is described, including the flapping amplitude, frequency, drag force, and mechanical energy of the filaments. Four typical vortex structures are observed in the wake of the filaments and are described as the coalesced vortices, symmetrical vortices, erratic vortices, and independent vortex streets. The vortex structures are closely related to the coupling modes and the dynamic characteristics of the filaments. As the Reynolds number is increased or as the bending rigidity is reduced, the filaments gain more energy and ordering of the coupling modes may change.
Superconducting low-inductance undulatory galvanometer microwave amplifier: Theory
Authors: Ribeill G. J. , Hover D. , Chen Y.-F. , Zhu S. , McDermott R.
Published: November 2011

We describe a novel scheme for low-noise phase-insensitive linear amplification at microwave frequencies based on the superconducting low-inductance undulatory galvanometer (SLUG). Direct integration of the junction equations of motion provides access to the full scattering matrix of the SLUG. We discuss the optimization of SLUG amplifiers and calculate amplifier gain and noise temperature in both the thermal and quantum regimes. Loading of the SLUG element by the finite input admittance is taken into account, and strategies for decoupling the SLUG from the higher-order modes of the input circuit are discussed. The microwave SLUG amplifier is expected to achieve noise performance approaching the standard quantum limit in the frequency range from 5–10 GHz, with gain around 15 dB for a single-stage device and instantaneous bandwidths of order 1 GHz.
X-ray photoelectron spectroscopy investigation of the Schottky barrier at low-k a-SiO(C):H/Cu interfaces
Authors: King S. W. , French M. , Jaehnig M. , Kuhn M. , French B.
Published: November 2011

In order to understand the fundamental mechanisms involved in electrical leakage in low-k/Cu interconnects, we have utilized x-ray photoelectron spectroscopy to determine the Schottky barrier present at interfaces formed by plasma enhanced chemical vapor deposition of low-k a-SiOxCy:H thin films on polished Cu substrates. We find the Schottky Barrier at this interface to range widely from 1 to >4 eV and to be dependent on the amount of network carbon incorporated into the a-SiOC:H thin films.
Generic Fe buffer layers for Fe-based superconductors: Epitaxial FeSe1−xTex thin films
Authors: Iida Kazumasa , Hänisch Jens , Schulze Michael , Aswartham Saicharan , Wurmehl Sabine , Büchner Bernd , Schultz Ludwig , Holzapfel Bernhard
Published: November 2011

Biaxially textured FeSe1−xTex films have been realized on Fe-buffered MgO substrates by pulsed laser deposition. Similar to the Fe/BaFe2As2 bilayers, the crystalline quality of FeSe1−xTex films exhibit a sharp out-of-plane and in-plane texture less than 0.9°. The Fe/FeSe1−xTex bilayers showed high superconducting transition temperatures of over 17 K. The angular-dependent critical current densities exhibit peaks positioned at H ⊥ c similar to other pnictide thin films. The volume pinning force of FeSe1−xTex in this direction is very strong compared with that of Co-doped BaFe2As2, due to a good matching between the interlayer distance in the c direction and the out-of-plane coherence length.
Measurements of beam current density and proton fraction of a permanent-magnet microwave ion source
Authors: Waldmann Ole , Ludewigt Bernhard
Published: November 2011

A permanent-magnet microwave ion source has been built for use in a high-yield, compact neutron generator. The source has been designed to produce up to 100 mA of deuterium and tritium ions. The electron-cyclotron resonance condition is met at a microwave frequency of 2.45 GHz and a magnetic field strength of 87.5 mT. The source operates at a low hydrogen gas pressure of about 0.15 Pa. Hydrogen beams with a current density of 40 mA/cm2 have been extracted at a microwave power of 450 W. The dependence of the extracted proton beam fraction on wall materials and operating parameters was measured and found to vary from 45% for steel to 95% for boron nitride as a wall liner material.
Chaotic phase synchronization in a modular neuronal network of small-world subnetworks
Authors: Yu Haitao , Wang Jiang , Liu Qiuxiang , Wen Jinxin , Deng Bin , Wei Xile
Published: November 2011

We investigate the onset of chaotic phase synchronization of bursting oscillators in a modular neuronal network of small-world subnetworks. A transition to mutual phase synchronization takes place on the bursting time scale of coupled oscillators, while on the spiking time scale, they behave asynchronously. It is shown that this bursting synchronization transition can be induced not only by the variations of inter- and intra-coupling strengths but also by changing the probability of random links between different subnetworks. We also analyze the effect of external chaotic phase synchronization of bursting behavior in this clustered network by an external time-periodic signal applied to a single neuron. Simulation results demonstrate a frequency locking tongue in the driving parameter plane, where bursting synchronization is maintained, even with the external driving. The width of this synchronization region increases with the signal amplitude and the number of driven neurons but decreases rapidly with the network size. Considering that the synchronization of bursting neurons is thought to play a key role in some pathological conditions, the presented results could have important implications for the role of externally applied driving signal in controlling bursting activity in neuronal ensembles.
First-principles calculations of Xe-adsorbed Pd(111) and Cu(111) surfaces with an empirical correction of van der Waals interactions
Authors: Sun X. , Yamauchi Y.
Published: November 2011

The adsorptions of Xe atoms on the Pd(111) and Cu(111) surfaces are investigated by first-principles calculations. The van der Waals interactions are considered in the optimization of the geometric structure. The equilibrium distance from the Xe atom to the topmost surface layer and the rumpling of the substrate are closer to the experimental data than by conventional calculations without including van der Waals interactions. The existence of the induced states, which are partially filled by electron back donation, is predicted by the calculated local density of states. The mechanism of the sublevel splitting of the 5p3/2 states is discussed. The differential electron densities are used to analyze the electron redistribution by the adsorption of Xe atoms.
Stability of steady flow through an axially corrugated pipe
Authors: Loh S. A. , Blackburn H. M.
Published: November 2011

The linear stability of steady flow in pipes with circular cross-section and sinusoidal axial variation in diameter is studied by finding global eigenmodes with axial wavelength commensurate with that of the wall corrugation, chosen to be equal to one pipe mean radius. The maximum peak-to-peak height of corrugation considered is approximately 8% of the mean diameter. At low corrugation amplitude and at low Reynolds numbers, the base flow remains attached to the wall, while at larger amplitudes and Reynolds numbers, an axisymmetric separation bubble forms within the corrugation. For all Reynolds numbers considered, flows remain stable to axisymmetric perturbations, but become unstable to standing-wave modes of low azimuthal wavenumber, with critical Reynolds number first falling, then increasing with increasing corrugation height. Both attached and separated flows exhibit similar types of instability modes, which in the case of separated flow are most energetic near the reattachment line of the base flow. The leading instability modes consist of counter-rotating vortices situated near the pipe wall.
Ignition of an exothermal reaction by collision between Al and Ni crystals
Authors: Delogu Francesco
Published: November 2011

Classical molecular dynamics methods have been used to investigate the atomic-scale dynamics of collisions between two Al and Ni crystals with rough surfaces. The crystals were approached along the direction perpendicular to the surfaces and simultaneously displaced along the direction parallel to them at relative velocities in the range between 1 and 10 nm ns−1. The mechanical stresses operating at collision determine a local deformation of Al and Ni lattices, accompanied by a significant temperature rise. As the Al melting point is reached, the Al crystal partially melts and Ni atoms start dissolving into the molten phase. The significant heat of mixing liberated further promotes the Al melting and the Ni dissolution processes. In the absence of neighboring Al-Ni interfaces, the heat dissipation processes and the limited rate of Ni dissolution gradually lead to the extinction of the reactive behavior. Conversely, the presence of Al-Ni interfaces in the vicinity of the Al-Ni one formed by collision permits the propagation of the high-temperature chemical reaction. It is shown that the ignition and propagation of the self-sustaining reaction is sensitive to the distance between Al-Ni interfaces and to their degree of chemical mixing.
Site specific metallic to semiconductor transition in selenium adsorbed armchair single wall carbon nanotubes
Authors: Krishnan Sridevi , Vadapoo Rajasekarakumar , Marin Carlos
Published: November 2011

Pristine armchair single wall carbon nanotubes (SWCNTs) are metallic; however, they undergo a transition to semiconductor under certain external perturbations. The effect of the bi-site perturbation created by selenium adsorption on electronic properties of armchair SWCNTs for a range of diameters are studied using first principles calculations. We find that the established rules of periodicity for the relative position of the adsorbates are not sufficient to predict a metal to semiconductor transition. By investigating the structural deformation induced in the nanotubes by the adsorbates, we show that the effects of all possible bi-site perturbations are not equivalent. We also show that this factor becomes significant to predict metallic to semiconductor transition on bi-site perturbed Se adsorbed armchair SWCNTs.
Development and integration of a LabVIEW-based modular architecture for automated execution of electrochemical catalyst testing
Authors: Topalov Angel A. , Katsounaros Ioannis , Meier Josef C. , Klemm Sebastian O. , Mayrhofer Karl J. J.
Published: November 2011

This paper describes a system for performing electrochemical catalyst testing where all hardware components are controlled simultaneously using a single LabVIEW-based software application. The software that we developed can be operated in both manual mode for exploratory investigations and automatic mode for routine measurements, by using predefined execution procedures. The latter enables the execution of high-throughput or combinatorial investigations, which decrease substantially the time and cost for catalyst testing. The software was constructed using a modular architecture which simplifies the modification or extension of the system, depending on future needs. The system was tested by performing stability tests of commercial fuel cell electrocatalysts, and the advantages of the developed system are discussed.
On the nature of electron correlation in C60
Authors: Stück David , Baker Thomas A. , Zimmerman Paul , Kurlancheek Westin , Head-Gordon Martin
Published: November 2011

The ground state restricted Hartree Fock (RHF) wave function of C60 is found to be unstable with respect to spin symmetry breaking, and further minimization leads to a significantly spin contaminated unrestricted Hartree Fock (UHF) solution (〈S2〉 = 7.5, 9.6 for singlet and triplet, respectively). The nature of the symmetry breaking in \documentclass[12pt]{minimal}\begin{document}$\rm {C_{60}}$\end{document}C60 relative to the radicaloid fullerene, \documentclass[12pt]{minimal}\begin{document}$\rm {C_{36}}$\end{document}C36, is assessed by energy lowering of the UHF solution, 〈S2〉, and the unpaired electron number. We conclude that the high value of each of these measures in \documentclass[12pt]{minimal}\begin{document}$\rm {C_{60}}$\end{document}C60 is not attributable to strong correlation behavior as is the case for \documentclass[12pt]{minimal}\begin{document}$\rm {C_{36}}$\end{document}C36. Instead, their origin is from the collective effect of relatively weak, global correlations present in the π space of both fullerenes. Second order perturbation (MP2) calculations of the singlet triplet gap are significantly more accurate with RHF orbitals than UHF orbitals, while orbital optimized opposite spin second order correlation (O2) performs even better.
Elimination of the weak inversion hump in Si3N4/InGaAs (001) gate stacks using an in situ NH3 pre-treatment
Authors: Krylov Igor , Gavrilov Arkady , Ritter Dan , Eizenberg Moshe
Published: November 2011

Silicon nitride thin films were deposited by plasma enhanced chemical vapor deposition on In0.53Ga0.47As (001) surfaces with and without NH3 pre-deposition treatments. The influence of the NH3 pre-deposition treatments on the electrical properties of the Si3N4/In0.53Ga0.47As interface was investigated by frequency dependent capacitance-voltage and conductance-voltage measurements. A fully unpinned C-V behavior was obtained for all samples. Samples that underwent NH3 pre-deposition treatment exhibited electrical characteristics with no evidence of the midgap interface states (Dit) effects in weak inversion, which are reported in the literature on In0.53Ga0.47As capacitors.
Confocal imaging of laminar and turbulent mixing in a microscale multi-inlet vortex nanoprecipitation reactor
Authors: Shi Yanxiang , Fox Rodney O. , Olsen Michael G.
Published: November 2011

Mass production of functional nanoparticles may be realized through flash nanoprecipiation in microscale reactors such as the multi-inlet vortex reactor (MIVR). A comprehensive understanding of mixing in the MIVR is required for process control and reactor design. Mixing in the MIVR is studied using a technique coupling laser induced fluorescence with confocal laser scanning microscopy. It is shown to provide meaningful qualitative and statistical data of the scalar field for analysis and comparison with numerical simulations. Data were collected for four flow rates, showing that mixing is incomplete even at the highest flow rate.
Encapsulation of a polyelectrolyte chain by an oppositely charged spherical surface
Authors: Wang Jiafang , Muthukumar M.
Published: November 2011

Using the ground state dominance approximation and a variational theory, we study the encapsulation of a polyelectrolyte chain by an oppositely charged spherical surface. The electrostatic attraction between the polyelectrolyte and the surface and the entropy loss of the encapsulated polyelectrolyte chain dictate the optimum conditions for encapsulation. Two scenarios of encapsulation are identified: entropy-dominated and adsorption-dominated encapsulation. In the entropy-dominated encapsulation regime, the polyelectrolyte chain is delocalized, and the optimum radius of the encapsulating sphere decreases with increasing the attraction. In the adsorption-dominated encapsulation regime, the polyelectrolyte chain is strongly localized near the surface, and the optimum radius increases with increasing the attraction. After identifying a universal encapsulation parameter, the dependencies of the optimum radius on the salt concentration, surface charge density, polymer charge density, and polymer length are explored.
Low-temperature grown GaAs heterojunction metal-semiconductor-metal photodetectors improve speed and efficiency
Authors: Currie Marc , Quaranta Fabio , Cola Adriano , Gallo Eric M. , Nabet Bahram
Published: November 2011

Low-temperature-grown GaAs (LT-GaAs) has a picosecond recombination lifetime, making a fast photodetector material but limiting carrier mobility and collection efficiency. Here, a metal-semiconductor-metal photodetector with a thin channel of regular-temperature GaAs (RT-GaAs) above LT-GaAs provides fast transit between contacts. A p-type delta doping layer below these layers produces a vertical electric field forcing optically generated electrons towards the channel. The AlGaAs/RT-GaAs heterojunction increases Schottky contacts, and the resulting 8–22 μm pitch photodetectors have low (<1-nA) dark current, 12-ps (oscilloscope-limited) pulsewidth, and 0.15-A/W responsivity. The devices demonstrate that fast LT-GaAs pulses are achievable with responsivity similar to RT-GaAs.
Mode separation of a single-frequency bi-modal elastic wave pulse by a phononic crystal
Authors: Sik Ma Pyung , Woong Kim Hoe , Hwan Oh Joo , Young Kim Yoon
Published: November 2011

Multiple wave modes in a signal can be effectively separated by frequency filtering or frequency-based methods as long as the modes propagate at different frequencies. However, they cannot be applied for the separation of multiple modes that propagate at the same frequency. This work shows that two wave modes contained in a single-frequency bi-modal signal can be separated if a specially engineered phononic crystal (PC) is employed. For demonstration, guided elastic wave experiments were performed in a thin aluminum plate in the middle of which a PC is inserted for mode separation.
Partially inverse spinel ZnFe2O4 with high saturation magnetization synthesized via a molten salt route
Authors: Wu Jiangtao , Li Nan , Xu Jun , Jiang Yaqi , Ye Zuo-Guang , Xie Zhaoxiong , Zheng Lansun
Published: November 2011

Materials with high saturation magnetization (Ms) is greatly demanded in modern soft magnetic applications. In this work, we synthesized partially inverse spinel ZnFe2O4 in micron scale with the highest Ms (Ms = 5.05 μB) among ferrites. What’s more, it exhibits high Curie temperature (640 K), high resistivity, and excellent thermo-stability. Through careful analyses, including Mössbauer spectroscopic, x-ray diffraction, and x-ray photo-electron spectroscopic measurements, it was concluded that the strong ferromagnetism of the as-prepared ZnFe2O4 resulted from its partially inverse spinel structure. These excellent properties indicate the as-prepared ZnFe2O4 is an ideal kind of soft magnet.
Real-time imaging of acoustic rectification
Authors: Danworaphong S. , Kelf T. A. , Matsuda O. , Tomoda M. , Tanaka Y. , Nishiguchi N. , Wright O. B. , Nishijima Y. , Ueno K. , Juodkazis S. , Misawa H.
Published: November 2011

We image gigahertz surface acoustic waves normally incident on a microscopic linear array of triangular holes—a generic “acoustic diode” geometry—with a real-time ultrafast optical technique. Spatiotemporal Fourier transforms reveal wave diffraction orders in k-space. Squared amplitude reflection and transmission coefficients for incidence on both sides of the array are evaluated and compared with numerical simulations. We thereby directly demonstrate acoustic rectification with an asymmetric structure.
Biotransformation of selenium and arsenic in multi-species biofilm
Authors: Yang Soo In , Lawrence John R. , Swerhone George D. W. , Pickering Ingrid J.
Published: November 2011

Environmental contextElevated levels of selenium and arsenic in the environment as a result of anthropogenic activities are creating significant concerns for the health of aquatic ecosystems. How biofilms, or aquatic microbial communities, interact with and chemically modify selenium and arsenic species has been examined. The results demonstrate that selenium and arsenic induce structural changes in biofilms, and concurrently undergo extensive biotransformation, in most cases to less bioavailable species. AbstractArsenic and selenium are both elements of concern especially when released into the environment by anthropogenic activity. Biofilms, or communities of microorganisms, can play important roles in biotransforming elements to less toxic chemical forms. This study used novel tools to characterise the fate of oxyanions (selenate, selenite, arsenate or arsenite) in multi-species biofilms inoculated from a source receiving coal mining effluent. Confocal laser scanning microscopy (CLSM) demonstrated a distinct biofilm morphology at elevated oxyanion concentrations. Selenium and arsenic K near-edge X-ray absorption spectroscopy (XAS) showed biofilm biotransformation of oxyanions; extended X-ray absorption fine structure (EXAFS) confirmed elemental selenium as a product. Micro X-ray fluorescence imaging combined with CLSM revealed highly localised reduced selenium species in the biofilm. Isolation and partial 16S rRNA gene sequencing suggested four principle bacterial genera were responsible. Biofilms can both detoxify and sequester selenium and arsenic, playing critical roles in their fate and effects in aquatic environments.
Giant mud crab (Scylla serrata) catches and climate drivers in Australia - a large scale comparison
Authors: Meynecke Jan-Olaf , Grubert Mark , Gillson Jonathan
Published: November 2011

Patterns in the Southern Oscillation Index (SOI) affect the life history of many aquatic organisms in the southern hemisphere. We examined the effect of this phenomenon and other factors (i.e. rainfall, river flow and sea surface temperature, SST) on the commercial harvest of the giant mud crab (Scylla serrata) in Australia, given the large inter-annual variations in the catch of this species over the last 15 years, particularly in the north. Regression models were applied to concurrent environmental and catch data for giant mud crab caught from 29 catchments that provided a combined harvest of >20 000 tonnes. Non-metric multidimensional scaling (nMDS) was also used to explore potential regional differences in catch trends. A combination of SOI, SST and rainfall/river flow explained 30–70% of the variability in commercial catches, with mean summer temperature being most influential at higher latitudes. The nMDS revealed distinct groupings of river systems that coincided with biogeographic regions. This work highlights the importance of climatic events on the harvest of giant mud crabs and reinforces the need to adopt a bioregional approach when assessing the performance of fisheries targeting this species.
Co-benefits of large-scale renewables in remote Australia: energy futures and climate change
Authors: Pittock Barrie
Published: November 2011

Desert/remote Australia is blessed with abundant natural energy resources from solar, geothermal and other renewable sources. If these were harnessed and connected appropriately desert/remote Australia could be not only energy self-sufficient but a net exporter. Generation of abundant, clean energy can also attract energy-intensive industries and provide local income and employment. Such co-benefits should be included in any cost-benefit analysis.
Regardless of renewable energy’s contribution to reducing climate change, the world is already committed to global warming and associated climate changes. Desert/remote Australia will thus inevitably get warmer, with implications for health, energy demand and other issues, and may be subject to increased extremes such as flooding, longer dry spells, more severe storms and coastal inundation.
In addition, the prospect of world demand for oil from conventional sources exceeding supply will likely lead to oil shortages, higher oil prices, and additional incentives to provide alternative energy supplies. The region is heavily reliant on diesel generators and fossil fuel-powered motor vehicles and airplanes for transport for within-region mobility, the importation of goods, the tourism industry and emergency medical services.
Without adaptation, climate change and peak oil will make living in desert/remote Australia less attractive, resulting in increased difficulty of attracting and retaining skilled workers, which would constrain development.
This paper focuses on the climate and energy-related impacts and potential responses. These are both a challenge and an opportunity. They could provide additional employment and income, thus helping remote communities to participate in the clean energy economy of the future and thus overcome some serious social problems. The paper attempts to review current knowledge and provoke debate on relevant investment strategies, and it teases out the questions in need of further research.
Agonist-induced PKC phosphorylation regulates GluK2 SUMOylation and kainate receptor endocytosis
Authors: Konopacki Filip A. , Jaafari Nadia , Rocca Dan L. , Wilkinson Kevin A. , Chamberlain Sophie , Rubin Philip , Kantamneni Sriharsha , Mellor Jack R. , Henley Jeremy M.
Published: November 2011

The surface expression and regulated endocytosis of kainate (KA) receptors (KARs) plays a critical role in neuronal function. PKC can modulate KAR trafficking, but the sites of action and molecular consequences have not been fully characterized. Small ubiquitin-like modifier (SUMO) modification of the KAR subunit GluK2 mediates agonist-evoked internalization, but how KAR activation leads to GluK2 SUMOylation is unclear. Here we show that KA stimulation causes rapid phosphorylation of GluK2 by PKC, and that PKC activation increases GluK2 SUMOylation both in vitro and in neurons. The intracellular C-terminal domain of GluK2 contains two predicted PKC phosphorylation sites, S846 and S868, both of which are phosphorylated in response to KA. Phosphomimetic mutagenesis of S868 increased GluK2 SUMOylation, and mutation of S868 to a nonphosphorylatable alanine prevented KA-induced SUMOylation and endocytosis in neurons. Infusion of SUMO-1 dramatically reduced KAR-mediated currents in HEK293 cells expressing WT GluK2 or nonphosphorylatable S846A mutant, but had no effect on currents mediated by the S868A mutant. These data demonstrate that agonist activation of GluK2 promotes PKC-dependent phosphorylation of S846 and S868, but that only S868 phosphorylation is required to enhance GluK2 SUMOylation and promote endocytosis. Thus, direct phosphorylation by PKC and GluK2 SUMOylation are intimately linked in regulating the surface expression and function of GluK2-containing KARs.
Constitutive coupling of a naturally occurring human alpha1a-adrenergic receptor genetic variant to EGFR transactivation pathway
Authors: Oganesian Anush , Yarov-Yarovoy Vladimir , Parks William C. , Schwinn Debra A.
Published: November 2011

We previously identified a naturally occurring human SNP, G247R, in the third intracellular loop of the α1a-adrenergic receptor (α1a-247R) and demonstrated that constitutive expression of α1a-247R results in twofold increased cell proliferation compared with WT. In the present study we elucidate molecular mechanisms and signal transduction pathways responsible for increased cell proliferation unique to α1a-247R, but not α1a-WT, α1b, or α1dAR subtypes. We show that elevated levels of matrix metalloproteinase-7 (MMP7) and a disintegrin and metalloproteinase-12 (ADAM12) in α1a-247R–expressing cells are responsible for EGF receptor (EGFR) transactivation, downstream ERK activation, and increased cell proliferation; this pathway is confirmed using MMP, EGFR, and ERK inhibitors. We demonstrate that EGFR transactivation and downstream ERK activation depends on increased shedding of heparin-binding EGF. Finally, we demonstrate that knockdown of MMP7 or β-arrestin1 by shRNAs results in attenuation of proliferation of cells expressing α1a-247R. Importantly, accelerated cell proliferation triggered by the α1a-247R is serum- and agonist-independent, providing unique evidence for constitutive active coupling to the β-arrestin1/MMP/EGFR transactivation pathway by any G protein-coupled receptor. These findings raise the possibility of a previously unexplored mechanism for sympathetically mediated human hypertension triggered by a naturally occurring human genetic variant.
A resolvable frozen conflict? Designing a settlement for Transnistria
Authors: Wolff Stefan
Published: November 2011

The conflict over Transnistria is a territorial dispute in which one of the conflict parties (Transnistria) seeks independence while the other (Moldova) aims to restore its full sovereignty and territorial integrity. For close to two decades, the situation has been stagnant: a cease-fire agreement signed in 1992 in Moscow between the Russian and Moldovan presidents at the time – Boris Yeltsin and Mircea Snegur – established a trilateral peacekeeping mission (Russia, Moldova, Transnistria) and a buffer zone along the Dniestr/Nistru River. Protected by these arrangements and an additional Russian military presence, Transnistria has developed into a de facto state of its own, albeit without international recognition and heavily dependent on Russia.
Delivering The Heart Truth® to Women Through Community Education
Authors: Long Terry , Taubenheim Ann M. , McDonough Sally , Austin Page , Wayman Jennifer , Temple Sarah
Published: November 2011

The Heart Truth® is a national education campaign sponsored by the National Heart, Lung, and Blood Institute of the National Institutes of Health, U.S. Department of Health and Human Services, to raise awareness among women that heart disease is their leading cause of death and to motivate them to take action for heart health. Launched in 2002 as a brand-driven social marketing effort, the campaign created the Red Dress as the national symbol for women and heart disease awareness. With the brand as a driving force, the campaign has made substantial progress toward its goal through a three-part implementation strategy: partnership development, media relations and use of social media, and education at the community level. This article reports on the development and results of the campaign's community programs that have delivered its messages and materials locally, especially to African-American and Hispanic women, two groups disproportionately affected by heart disease. Most of the local efforts were a mix of communitywide awareness building and more intensive small-group education. The article reports on lessons learned, including pros and cons of working through national organizations with local infrastructures, the advantage of using existing turnkey materials, and the implications of the choice to use scarce resources for educational programming rather than extensive formal evaluation.
Reliability and criterion validity of the Self‐Administered Physical Activity Checklist in Greek children
Authors: Gioxari Aristea , Kavouras Stavros A. , Tambalis Konstantinos D. , Maraki Maria , Kollia Maria , Sidossis Labros S.
Published: November 2011

The purpose of this study was to assess the test–retest reliability and criterion validity the Self‐Administered Physical Activity Checklist (SAPAC) translated into the Greek language. To evaluate reliability, 72 students (35 girls and 37 boys) of the fifth and sixth grade completed SAPAC on two separate occasions, two weeks apart. Internal consistency was determined with Cronbach alpha coefficient and test–retest reliability with the intraclass correlation coefficient (ICC). To evaluate criterion validity, the RT3 Research Tracker accelerometer was used as standard measure, in 90 randomly selected Greek children (51 girls and 39 boys), aged between 10 and 13. Each subject participated for two consecutive days. On day one, an accelerometer was fitted when school started. On day two, the accelerometers were returned and each subject completed the questionnaire. The internal consistency and the test–retest reliability of SAPAC on total metabolic equivalent (MET) score, MET score of low physical activities (LPA) and MET score of moderate to vigorous physical activities (MVPA) were very satisfactory (all Cronbach's alpha > 0.87, and all ICC > 0.85, P <0.001). The Kendall's tau‐b test revealed that the degree of agreement between SAPAC and RT3 accelerometer on total MET score and MET score of MVPA were 0.31 and 0.37, respectively (P <0.01). It was concluded that the Greek translated version of SAPAC is a reliable questionnaire that provides valid estimates of total, as well as moderate to vigorous activities MET scores.
High Resolution Crossed Molecular Beams Study on the F+HD→DF+H Reaction at Collision Energy of 8.19–18.98 kJ/mol
Authors: Dong Wen-rui , Xiao Chun-lei , Wang Tao , Dai Dong-xu , Wang Xiu-yan , Yang Xue-ming
Published: November 2011

The crossed beams scattering dynamics of the F+HD→DF+H reaction have been studied at collision energies ranging from 8.19 kJ/mol to 18.98 kJ/mol using the high resolution H-atom Rydberg tagging time-of-flight method. Product rotational state-resolved differential cross sections have been measured. Most of the DF products are backward scattered at low collision energies and then gradually shift to the sideway as the collision energy increases. In addition to the backward and sideway scatterings, we have also observed the DF(v′ = 4) product in the forward direction for the first time for this reaction. The forward scattering DF(v = 4) product also increases with the collision energy. Angular and collision energy dependence of the product energy disposals in different degrees of freedom have been determined. Collision energy dependence of the vibrational branching ratios has also been examined. Possible dynamical origins of the forward scattering DF(v′=4) products were discussed.
Theoretical Investigation on Triplet Excitation Energy Transfer in Fluorene Dimer
Authors: Si Yu-bing , Zhong Xin-xin , Zhang Wei-wei , Zhao Yi
Published: November 2011

Triplet-triplet energy transfer in fluorene dimer is investigated by combining rate theories with electronic structure calculations. The two key parameters for the control of energy transfer, electronic coupling and reorganization energy, are calculated based on the diabatic states constructed by the constrained density functional theory. The fluctuation of the electronic coupling is further revealed by molecular dynamics simulation. Succeedingly, the diagonal and off-diagonal fluctuations of the Hamiltonian are mapped from the correlation functions of those parameters, and the rate is then estimated both from the perturbation theory and wavepacket diffusion method. The results manifest that both the static and dynamic fluctuations enhance the rate significantly, but the rate from the dynamic fluctuation is smaller than that from the static fluctuation.
Quantum Mechanics Rate Constant for the N+ND Reaction
Authors: Zhang Ai-jie , He Guo-zhong
Published: November 2011

We present nonadiabatic quantum dynamical calculations on the two coupled potential energy surfaces (12A′ and 22A′) [J. Theor. Comput. Chem. 8, 849 (2009)] for the reaction. Initial state-resolved reaction probabilities and cross sections for the N+ND→N2+D reaction and N′+ND→N+N′D reaction for collision energies of 5 meV to 1.0 eV are determined, respectively. It is found that the N+ND→N2+D reaction is dominated in the N+ND reaction. In addition, we obtained the rate constants for the N+ND→N2+D reaction which demand further experimental investigations.
Ultrafast Dynamics Through Conical Intersections in 2,6-dimethylpyridine Studied with Time-resolved Photoelectron Imaging
Authors: Qiu Xue-jun , Zhu Rong-shu , Xu Yan-qi , Bumaliya Abulimiti , Zhang Song , Zhang Bing
Published: November 2011

The ultrafast dynamics through conical intersections in 2,6-dimethylpyridine has been studied by femtosecond time-resolved photoelectron imaging coupled with time-resolved mass spectroscopy. Upon absorption of 266 nm pump laser, 2,6-dimethylpyridine is excited to the S2 state with a ππ* character from S0 state. The time evolution of the parent ion signals consists of two exponential decays. One is a fast component on a timescale of 635 fs and the other is a slow component with a timescale of 4.37 ps. Time-dependent photo-electron angular distributions and energy-resolved photoelectron spectroscopy are extracted from time-resolved photoelectron imaging and provide the evolutive information of S2 state. In brief, the ultrafast component is a population transfer from S2 to S1 through the S2/S1 conical intersections, the slow component is attributed to simultaneous IC from the S2 state and the higher vibrational levels of S1 state to S0 state, which involves the coupling of S2/S0 and S1/S0 conical intersections. Additionally, the observed ultrafast S2→S1 transition occurs only with an 18% branching ratio.
Photoelectron Imaging of AgOCH3− and Ag−(CH3OH)x(x= 1, 2)
Authors: Chi Chao-xian , Xie Hua , Cong Ran , Tang Zi-chao , Zhou Ming-fei
Published: November 2011

The AgOCH3− and Ag−(CH3OH)x (x = 1, 2) anions are studied by photoelectron imaging as well as ab initio calculations. The adiabatic and vertical detachment energies (ADE and VDE) of AgOCH3− are determined as 1.29(2) and 1.34(2) eV, respectively, from the vibrational resolved photoelectron spectrum. The Ag−(CH3OH)1,2 anionic complexes are characterized as metal atomic anion solvated by the CH3OH molecules with the electron mainly localized on the metal. The photoelectron spectra of Ag−(CH3OH)x(x = 0, 1, 2) show a gradual increase in VDE with increasing x, due to the solvent stabilization. Evidence for the methanol-methanol hydrogen bonding interactions appears when the Ag− is solvated by two methanol molecules.
Photophysical Property of Photoactive Molecules with Multibranched Push-Pull Structures
Authors: Wang Ying-ying , Ma Xiao-nan , Vdović Silvije , Yan Lin-yin , Wang Xue-fei , Guo Qian-jin , Xia An-dong
Published: November 2011

The structure-property characteristics of a series of newly synthesized intramolecular charge-transfer (ICT) compounds, single-branch monomer with triphenylmethane as electron donor and 2,1,3-benzothiadiazole as acceptor, the corresponding two-branch dimer and three-branch trimer, have been investigated by means of steady-state and femtosecond time-resolved stimulated emission fluorescence depletion (FS TR-SEP FD) techniques in different polar solvents. The TD-DFT calculations are further performed to explain the observed ICT properties. The interpretation of the experimental results is based on the comparative studies of the series of compounds which have increased amount of identical branch moiety. The similarity of the absorption and fluorescence spectra as well as strong solvent-dependence of the spectral properties for the three compounds reveal that the excited state of the dimer and trimer are nearly the same with that of the monomer, which may localize on one branch. It is found that polar excited state emerged through multidimensional intramolecular charge transfer from the donating moiety to the acceptor upon excitation, and quickly relaxed to one branch before emission. Even so, the red-shift in the absorption and emission spectra and decreased fluorescence radiative lifetime with respect to their monomer counterpart still suggest some extent delocalization of excited state in the dimer and trimer upon excitation. The similar behavior of their excited ICT state is demonstrated by FS TR-SEP FD measurements, and shows that the trimer has the largest charge-separate extent in all studied three samples. Finally, steady-state excitation anisotropy measurements has further been carried out to estimate the nature of the optical excitation and the mechanism of energy redistribution among the branches, where no plateau through the ICT band suggests the intramolecular excitation transfer process between the branches in dimer and trimer.
Classification of VxOyqClusters by Δ = 2y+q−5x
Authors: Ma Yan-ping , Zhao Yan-xia , Li Zi-yu , Ding Xun-lei , He Sheng-gui
Published: November 2011

Vanadium oxide clusters VxOyq (x ≤ 8, q = 0, ±1) are classified according to the oxidation index (Δ=2y+q−5x) of each cluster. Density functional calculations indicate that clusters with the same oxidation index tend to have similar bonding characters, electronic structures, and reactivities. This general rule leads to the findings of new possible ground state structures for V2O6 and V3O6+ clusters. This successful application of the classification method on vanadium oxide clusters proves that this method is very effective in studying the bonding properties of early transition metal oxide clusters.