bluuebunny/crossref_metadata_2025 huggingface dataset:
Modified approach for high frequency dielectric characterization of thinly metallized soft polymer film using grounded coplanar waveguide
Authors: Baron Samuel , Nadaud Kevin , Guiffard Benoit , Sharaiha Ala , Seveyrat Laurence
Published: September 2015

In this paper, we introduce the dielectric characterization of soft polymer, polyurethane (PU), between 1 and 31 GHz frequency band using Grounded CoPlanar Waveguide (GCPW) lines with a modified analytical method. The unavoidable thin metallization (1 μm) of GCPW lines on polyurethane yields high conductor losses, which contribute to the extracted global losses up to 58% at 4 GHz. In order to get more precisely the dielectric losses, a modification of an already existing analytical model by coupling it with 3D electromagnetic simulations is proposed, which allows to estimate and subtract quickly the conductor losses. The measurements indicated that polyurethane relative permittivity ranges from 3.49 to 2.65 and the loss tangent was about 0.08, which is in agreement with the state of the art on this grade of PU as well as the Metal-Insulator-Metal capacitors characterizations (from 10−1 to 107 Hz and from 2 × 108 to 5 × 109 Hz). The proposed approach may open a fast and simple way for precisely determining the microwave dielectric properties of (ultra) soft polymers in a large bandwidth.
Density of hydrophobically confined deeply cooled water investigated by small angle X-ray scattering
Authors: Liu Kao-Hsiang , Zhang Yang , Jeng U-Ser , Mou Chung-Yuan
Published: September 2015

Water’s behavior near hydrophobic surfaces has attracted great attention due to chemical and geological applications. Here, we report small angle X-ray scattering (SAXS) studies of water confined in the hydrophobic nanoporous carbon material, CMK-1-14, from ambient to deeply cooled temperatures. By monitoring the scattering intensity of the first Bragg peak, which is directly related to the scattering length density contrast between the carbon matrix and the confined water, the average density of the hydrophobically confined water was determined from 300 K to 150 K at ambient pressure. Furthermore, differential scanning calorimetry and X-ray diffraction measurements showed that the majority of such hydrophobically confined water did not crystallize in the investigated temperature range. By exploiting the fast speed of SAXS measurements and the continuous temperature ramping, the average density profile and the deduced thermal expansion coefficient (αp) were obtained. We found that the well-known density maximum of water at 277 K downshifted to 260 K, and the density minimum which has been observed in hydrophilic confinement disappeared. In addition, the previously measured large density decreasing of 18% at low temperature was recalibrated to a more reasonable 10% instead. Consequently, the recalculated αp peak was found to be quite similar to that of the water confined in hydrophilic MCM-41-S-15 suggesting an intrinsic property of water, which does not sensitively depend on the confinement surface.
On the electron dynamics during island coalescence in asymmetric magnetic reconnection
Authors: Cazzola E. , Innocenti M. E. , Markidis S. , Goldman M. V. , Newman D. L. , Lapenta G.
Published: September 2015

We present an analysis of the electron dynamics during rapid island merging in asymmetric magnetic reconnection. We consider a doubly periodic system with two asymmetric transitions. The upper layer is an asymmetric Harris sheet of finite width perturbed initially to promote a single reconnection site. The lower layer is a tangential discontinuity that promotes the formation of many X-points, separated by rapidly merging islands. Across both layers, the magnetic field and the density have a strong jump, but the pressure is held constant. Our analysis focuses on the consequences of electron energization during island coalescence. We focus first on the parallel and perpendicular components of the electron temperature to establish the presence of possible anisotropies and non-gyrotropies. Thanks to the direct comparison between the two different layers simulated, we can distinguish three main types of behavior characteristic of three different regions of interest. The first type represents the regions where traditional asymmetric reconnections take place without involving island merging. The second type of regions instead shows reconnection events between two merging islands. Finally, the third regions identify the regions between two diverging island and where typical signature of reconnection is not observed. Electrons in these latter regions additionally show a flat-top distribution resulting from the saturation of a two-stream instability generated by the two interacting electron beams from the two nearest reconnection points. Finally, the analysis of agyrotropy shows the presence of a distinct double structure laying all over the lower side facing the higher magnetic field region. This structure becomes quadrupolar in the proximity of the regions of the third type. The distinguishing features found for the three types of regions investigated provide clear indicators to the recently launched Magnetospheric Multiscale NASA mission for investigating magnetopause reconnection involving multiple islands.
Signatures of quantum radiation reaction in laser-electron-beam collisions
Authors: Wang H. Y. , Yan X. Q. , Zepf M.
Published: September 2015

Electron dynamics in the collision of an electron beam with a high-intensity focused ultrashort laser pulse are investigated using three-dimensional QED particle-in-cell (PIC) simulations, and the results are compared with those calculated by classical Landau and Lifshitz PIC simulations. Significant differences are observed from the angular dependence of the electron energy distribution patterns for the two different approaches, because photon emission is no longer well approximated by a continuous process in the quantum radiation-dominated regime. The stochastic nature of photon emission results in strong signatures of quantum radiation-reaction effects under certain conditions. We show that the laser spot size and duration greatly influence these signatures due to the competition of QED effects and the ponderomotive force, which is well described in the classical approximation. The clearest signatures of quantum radiation reaction are found in the limit of large laser spots and few cycle pulse durations.
Two-fluid equilibrium with flow: FLOW2
Authors: Guazzotto L. , Betti R.
Published: September 2015

The effects of finite macroscopic velocities on axisymmetric ideal equilibria are examined using the two-fluid (ions and electrons) model. A new equilibrium solver, the code FLOW2, is introduced for the two-fluid model and used to investigate the importance of various flow patterns on the equilibrium of tight aspect ratio (NSTX) and regular tokamak (DIII-D) configurations. Several improvements to the understanding and calculation of two-fluid equilibria are presented, including an analytical and numerical proof of the single-fluid and static limits of the two-fluid model, a discussion of boundary conditions, a user-friendly free-function formulation, and the explicit evaluation of velocity components normal to magnetic surfaces.
Amplification of a seed pumped by a chirped laser in the strong coupling Brillouin regime
Authors: Schluck F. , Lehmann G. , Spatschek K. H.
Published: September 2015

Seed amplification via Brillouin backscattering of a long pump laser-pulse is considered. The interaction takes place in the so called strong coupling regime. Pump chirping is applied to mitigate spontaneous Raman backscattering of the pump before interacting with the seed. The strong coupling regime facilitates stronger exponential growth and narrower seeds compared to the so called weak coupling regime, although in the latter the scaling with pump amplitude is stronger. Strong coupling is achieved when the pump laser amplitude exceeds a certain threshold. It is shown how the chirp influences both the linear as well as the nonlinear amplification process. First, linear amplification as well as the seed profiles are determined in dependence of the chirping rate. In contrast to the weak coupling situation, the evolution is not symmetric with respect to the sign of the chirping rate. In the nonlinear stage of the amplification, we find an intrinsic chirp of the seed pulse even for an un-chirped pump. We show that chirping the pump may have a strong influence on the shape of the seed in the nonlinear amplification phase. Also, the influence of pump chirp on the efficiency of Brillouin seed amplification is discussed.
Strain-induced structural modifications and size-effects in silica nanowires
Authors: Tang Chun , Dávila Lilian P.
Published: September 2015

This study investigates the structural transformations and properties of silica glass nanowires under tensile loading via molecular dynamics simulations using the BKS (Beest-Kramer-Santen) interatomic potential. Surface states of the elongated nanowires were quantified using radial density distributions, while structural transformations were evaluated via ring size distribution analysis. The radial density distributions indicate that the surface states of these silica nanowires are significantly different than those of their interior. Ring size analysis shows that the ring size distributions remain mainly unchanged within the elastic region during tensile deformation, however they vary drastically beyond the onset of plastic behavior and reach plateaus when the nanowires break. The silica nanowires undergo structural changes which correlate with strain energy and ring size distribution variations. It is also found that the ring size distribution (and strain energy) variations are dependent on the diameter of the silica nanowires. Interestingly, for ultrathin nanowires (diameters < 5 .0 nm), the variation of ring size distributions shows a distinct trend with respect to tensile strain, indicating that the surface states play a key role in both modifying the mechanical properties and structural characteristics. These results for ultrathin nanowires are consistent with prior theoretical and simulation predictions. The overall findings in this study provide key insights into the novel properties of nano-sized amorphous materials, and are aimed to inspire further experiments.
Seniority number description of potential energy surfaces: Symmetric dissociation of water, N2, C2, and Be2
Authors: Bytautas Laimutis , Scuseria Gustavo E. , Ruedenberg Klaus
Published: September 2015

The present study further explores the concept of the seniority number (Ω) by examining different configuration interaction (CI) truncation strategies in generating compact wave functions in a systematic way. While the role of Ω in addressing static (strong) correlation problem has been addressed in numerous previous studies, the usefulness of seniority number in describing weak (dynamic) correlation has not been investigated in a systematic way. Thus, the overall objective in the present work is to investigate the role of Ω in addressing also dynamic electron correlation in addition to the static correlation. Two systematic CI truncation strategies are compared beyond minimal basis sets and full valence active spaces. One approach is based on the seniority number (defined as the total number of singly occupied orbitals in a determinant) and another is based on an excitation-level limitation. In addition, molecular orbitals are energy-optimized using multiconfigurational-self-consistent-field procedure for all these wave functions. The test cases include the symmetric dissociation of water (6-31G), N2 (6-31G), C2 (6-31G), and Be2 (cc-pVTZ). We find that the potential energy profile for H2O dissociation can be reasonably well described using only the Ω = 0 sector of the CI wave function. For the Be2 case, we show that the full CI potential energy curve (cc-pVTZ) is almost exactly reproduced using either Ω-based (including configurations having up to Ω = 2 in the virtual-orbital-space) or excitation-based (up to single-plus-double-substitutions) selection methods, both out of a full-valence-reference function. Finally, in dissociation cases of N2 and C2, we shall also consider novel hybrid wave functions obtained by a union of a set of CI configurations representing the full valence space and a set of CI configurations where seniority-number restriction is imposed for a complete set (full-valence-space and virtual) of correlated molecular orbitals, simultaneously. We discuss the usefulness of the seniority number concept in addressing both static and dynamic electron correlation problems along dissociation paths.
Dynamics of tetrahydrofuran as minority component in a mixture with poly(2-(dimethylamino)ethyl methacrylate): A neutron scattering and dielectric spectroscopy investigation
Authors: Goracci G. , Arbe A. , Alegría A. , Lohstroh W. , Su Y. , Colmenero J.
Published: September 2015

We have investigated a mixture of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and tetrahydrofuran (THF) (70 wt. % PDMAEMA/30 wt. % THF) by combining dielectric spectroscopy and quasielastic neutron scattering (QENS) on a labelled sample, focusing on the dynamics of the THF molecules. Two independent processes have been identified. The “fast” one has been qualified as due to an internal motion of the THF ring leading to hydrogen displacements of about 3 Å with rather broadly distributed activation energies. The “slow” process is characterized by an Arrhenius-like temperature dependence of the characteristic time which persists over more than 9 orders of magnitude in time. The QENS results evidence the confined nature of this process, determining a size of about 8 Å for the volume within which THF hydrogens’ motions are restricted. In a complementary way, we have also investigated the structural features of the sample. This study suggests that THF molecules are well dispersed among side-groups nano-domains in the polymer matrix, ruling out a significant presence of clusters of solvent. Such a good dispersion, together with a rich mobility of the local environment, would prevent cooperativity effects to develop for the structural relaxation of solvent molecules, frustrating thereby the emergence of Vogel-Fulcher-like behavior, at least in the whole temperature interval investigated.
Review of using gallium nitride for ionizing radiation detection
Authors: Wang Jinghui , Mulligan Padhraic , Brillson Leonard , Cao Lei R.
Published: September 2015

With the largest band gap energy of all commercial semiconductors, GaN has found wide application in the making of optoelectronic devices. It has also been used for photodetection such as solar blind imaging as well as ultraviolet and even X-ray detection. Unsurprisingly, the appreciable advantages of GaN over Si, amorphous silicon (a-Si:H), SiC, amorphous SiC (a-SiC), and GaAs, particularly for its radiation hardness, have drawn prompt attention from the physics, astronomy, and nuclear science and engineering communities alike, where semiconductors have traditionally been used for nuclear particle detection. Several investigations have established the usefulness of GaN for alpha detection, suggesting that when properly doped or coated with neutron sensitive materials, GaN could be turned into a neutron detection device. Work in this area is still early in its development, but GaN-based devices have already been shown to detect alpha particles, ultraviolet light, X-rays, electrons, and neutrons. Furthermore, the nuclear reaction presented by 14N(n,p)14C and various other threshold reactions indicates that GaN is intrinsically sensitive to neutrons. This review summarizes the state-of-the-art development of GaN detectors for detecting directly and indirectly ionizing radiation. Particular emphasis is given to GaN's radiation hardness under high-radiation fields.
Investigation of an X-band gigawatt long pulse multi-beam relativistic klystron amplifier
Authors: Liu Zhenbang , Huang Hua , Lei Lurong , Jin Xiao , Zhu Lei , Wang Ganping , He Hu , Wu Yao , Ge Yi , Yuan Huan , Chen Zhaofu
Published: September 2015

To achieve a gigawatt-level long pulse radiation power in X-band, a multi-beam relativistic klystron amplifier is proposed and studied experimentally. By introducing 18 electron drift tubes and extended interaction cavities, the power capacity of the device is increased. A radiation power of 1.23 GW with efficiency of 41% and amplifier gain of 46 dB is obtained in the particle-in-cell simulation. Under conditions of a 10 Hz repeat frequency and an input RF power of 30 kW, a radiation power of 0.9 GW, frequency of 9.405 GHz, pulse duration of 105 ns, and efficiency of 30% is generated in the experiment, and the amplifier gain is about 45 dB. Both the simulation and the experiment prove that the multi-beam relativistic klystron amplifier can generate a long pulse GW-level radiation power in X-band.
Thermal conductivity measurements in phase change materials under freezing in presence of nanoinclusions
Authors: Angayarkanni S. A. , Philip John
Published: September 2015

We study the thermal properties and internal microstructures of n-hexadecane alkane containing nanoinclusions of copper nanowire, multi walled carbon nanotube, and graphene nanoplatelets of different volume fractions. Just below the freezing point, a large thermal contrast is observed in all the three systems. The thermal conductivity decreases with temperature below the freezing temperature and stabilizes at ∼10 °C below the freezing point. More than 100% of thermal conductivity enhancement is observed with 0.01 wt. % of nanofillers during the liquid to solid phase change. It is speculated that the reduction in the interfacial thermal resistance and the internal stress generated during the first order phase transition, due to the presence of nanoinclusions at grain boundaries of alkane crystals, led to the observed increase in the thermal conductivity. We found that an optimal nanoparticle loading with the space filling agglomerates in a phase change alkane can provide an extremely large thermal conductivity. Though the thermal conductivity enhancement at higher particle loading was independent of the bulk thermal conductivity of dispersed nanomaterials, an anomalously large thermal contrast is observed at a very low concentration in copper nanowire suspension. These results provide new approaches to achieve large thermal storage in organic phase change materials.
Birefringence and refractive indices of wurtzite GaN in the transparency range
Authors: Shokhovets S. , Himmerlich M. , Kirste L. , Leach J. H. , Krischok S.
Published: September 2015

Birefringence and anisotropic refractive indices of wurtzite GaN within the spectral range from 0.58 eV to 3.335 eV were determined combining optical retardation and spectroscopic ellipsometry measurements on a series of undoped m- and c-plane GaN bulk substrates grown by hydride vapor phase epitaxy. It is observable that the birefringence has a maximum close to the absorption edge and a weak broad minimum in near-IR range. A quantitative explanation of the whole data is given in terms of contributions to the optical response of GaN due to discrete excitons, Coulomb enhanced band-to-band optical transitions near the E0 critical point of the band structure, high-energy optical transitions, and infrared active optical phonon modes which are different for the ordinary and extraordinary waves both in magnitude and in spectral dependence.
Assessing photocatalytic power of g-C3N4 for solar fuel production: A first-principles study involving quasi-particle theory and dispersive forces
Authors: Osorio-Guillén J. M. , Espinosa-García W. F. , Moyses Araujo C.
Published: September 2015

First-principles quasi-particle theory has been employed to assess catalytic power of graphitic carbon nitride, g-C3N4, for solar fuel production. A comparative study between g-h-triazine and g-h-heptazine has been carried out taking also into account van der Waals dispersive forces. The band edge potentials have been calculated using a recently developed approach where quasi-particle effects are taken into account through the GW approximation. First, it was found that the description of ground state properties such as cohesive and surface formation energies requires the proper treatment of dispersive interaction. Furthermore, through the analysis of calculated band-edge potentials, it is shown that g-h-triazine has high reductive power reaching the potential to reduce CO2 to formic acid, coplanar g-h-heptazine displays the highest thermodynamics force toward H2O/O2 oxidation reaction, and corrugated g-h-heptazine exhibits a good capacity for both reactions. This rigorous theoretical study shows a route to further improve the catalytic performance of g-C3N4.
Sampling reactive pathways with random walks in chemical space: Applications to molecular dissociation and catalysis
Authors: Habershon Scott
Published: September 2015

Automatically generating chemical reaction pathways is a significant computational challenge, particularly in the case where a given chemical system can exhibit multiple reactants and products, as well as multiple pathways connecting these. Here, we outline a computational approach to allow automated sampling of chemical reaction pathways, including sampling of different chemical species at the reaction end-points. The key features of this scheme are (i) introduction of a Hamiltonian which describes a reaction “string” connecting reactant and products, (ii) definition of reactant and product species as chemical connectivity graphs, and (iii) development of a scheme for updating the chemical graphs associated with the reaction end-points. By performing molecular dynamics sampling of the Hamiltonian describing the complete reaction pathway, we are able to sample multiple different paths in configuration space between given chemical products; by periodically modifying the connectivity graphs describing the chemical identities of the end-points we are also able to sample the allowed chemical space of the system. Overall, this scheme therefore provides a route to automated generation of a “roadmap” describing chemical reactivity. This approach is first applied to model dissociation pathways in formaldehyde, H2CO, as described by a parameterised potential energy surface (PES). A second application to the HCo(CO)3 catalyzed hydroformylation of ethene (oxo process), using density functional tight-binding to model the PES, demonstrates that our graph-based approach is capable of sampling the intermediate paths in the commonly accepted catalytic mechanism, as well as several secondary reactions. Further algorithmic improvements are suggested which will pave the way for treating complex multi-step reaction processes in a more efficient manner.
UV-Vis optoelectronic properties of α-SnWO4: A comparative experimental and density functional theory based study
Authors: Ziani Ahmed , Harb Moussab , Noureldine Dalal , Takanabe Kazuhiro
Published: September 2015

We report a combined experimental and theoretical study on the optoelectronic properties of α-SnWO4 for UV-Vis excitation. The experimentally measured values for thin films were systematically compared with high-accuracy density functional theory and density functional perturbation theory using the HSE06 functional. The α-SnWO4 material shows an indirect bandgap of 1.52 eV with high absorption coefficient in the visible-light range (>2 × 105 cm−1). The results show relatively high dielectric constant (>30) and weak diffusion properties (large effective masses) of excited carriers.
Role of induced vortex interaction in a semi-active flapping foil based energy harvester
Authors: Wu J. , Chen Y. L. , Zhao N.
Published: September 2015

The role of induced vortex interaction in a semi-active flapping foil based energy harvester is numerically examined in this work. A NACA0015 airfoil, which acts as an energy harvester, is placed in a two-dimensional laminar flow. It performs an imposed pitching motion that subsequently leads to a plunging motion. Two auxiliary smaller foils, which rotate about their centers, are arranged above and below the flapping foil, respectively. As a consequence, the vortex interaction between the flapping foil and the rotating foil is induced. At a Reynolds number of 1100 and the position of the pitching axis at one-third chord, the effects of the distance between two auxiliary foils, the phase difference between the rotating motion and the pitching motion as well as the frequency of pitching motion on the power extraction performance are systematically investigated. It is found that compared to the single flapping foil, the efficiency improvement of overall power extraction for the flapping foil with two auxiliary foils can be achieved. Based on the numerical analysis, it is indicated that the enhanced power extraction, which is caused by the increased lift force, thanks to the induced vortex interaction, directly benefits the efficiency enhancement.
Performance optimization of p-n homojunction nanowire-based piezoelectric nanogenerators through control of doping concentration
Authors: Liu Guocheng , Abdel-Rahman Eihab , Ban Dayan
Published: September 2015

This paper demonstrates a series of flexible transparent ZnO p-n homojunction nanowire-based piezoelectric nanogenerators (NGs) with different p-doping concentrations. The lithium-doped segments are grown directly and consecutively on top of intrinsic nanowires (n-type). When characterized under cyclic compressive strains, the overall NG performance is enhanced by up to eleven-fold if the doping concentration is properly controlled. This improvement is attributable to reduction in the mobile charge screening effect and optimization of the NGs' internal electrical characteristics. Experimental results also show that an interfacial MoO3 barrier layer, at an optimized thickness of 5–10 nm, reduces leakage current and substantially improves piezoelectric NG performance.
Radiation directivity rotation by acoustic metamaterials
Authors: Jiang Xue , Zhang Likun , Liang Bin , Zou Xin-ye , Cheng Jian-chun
Published: September 2015

We use a metamaterial-based scheme to rotate the radiation directivity of sound radiated by a source surrounded by the structure. The rotation is demonstrated through both numerical simulations and experiments. The performance persists within a broadband and is entirely independent of the location and pattern of source inside, suggesting great potential in various practical scenarios where both the signal frequency and source position may vary significantly. We have also investigated the possibility to realize versatile controls of radiation direction by tailoring the structural parameters. Our design with special directivity-steering capability may open route to loudspeaker and auditorium acoustics designs and medical ultrasound applications.
Thermal transport through GaN–SiC interfaces from 300 to 600 K
Authors: Ziade Elbara , Yang Jia , Brummer Gordie , Nothern Denis , Moustakas Theodore , Schmidt Aaron J.
Published: September 2015

Silicon carbide is used as a substrate for high-power GaN devices because of its closely matched lattice spacing with GaN and its high thermal conductivity. In these devices, thermal resistance at the GaN–SiC interface is a bottleneck to heat flow, making this property an important factor in device design. In this letter, we report the first measurements of the thermal boundary conductance of epitaxial GaN grown directly on SiC without a transition layer. We find that the thermal boundary conductance increases from approximately 230 MW/m2K at 300 K to 330 MW/m2K at 600 K. Our measured values are in good qualitative agreement with the diffuse mismatch model for thermal boundary conductance and are in good quantitative agreement when we include a correction factor based on the ratio of Debye temperatures of the two materials. We also report the thermal conductivity of the GaN film, the thermal conductivity of 4H-SiC, and the thermal boundary conductance between Ni and GaN.
Geodesic acoustic modes in tokamak plasmas with a radial equilibrium electric field
Authors: Zhou Deng
Published: September 2015

The dispersion relation of geodesic acoustic modes in the tokamak plasma with an equilibrium radial electric field is derived and analyzed. Multiple branches of eigenmodes have been found, similar to the result given by the fluid model with a poloidal mass flow. Frequencies and damping rates of both the geodesic acoustic mode and the sound wave increase with respect to the strength of radial electric field, while the frequency and the damping rate of the lower frequency branch slightly decrease. Possible connection to the experimental observation is discussed.
Hybrid stacking structure of electroplated copper onto graphene for future interconnect applications
Authors: Su Ya-Wen , Wu Cen-Shawn , Liu Chih-Hua , Lin Hung-Yi , Chen Chii-Dong
Published: September 2015

We show the feasibility of copper electroplating using graphene as a seed layer. Thermal annealing of the as-plated copper-graphene hybrid system promotes permeation of copper into graphene, forming an intermixing layer with enlarged lattice constant. It is shown that this intermixing layer blocks the diffusion of copper into the bottom SiO2/Si substrate at temperatures up to 900 °C. The electroplating process is comparable with current semiconductor fabrication technology. This hybrid system can serve as interconnect in the integrated circuits.
Active terahertz device based on optically controlled organometal halide perovskite
Authors: Zhang Bo , Lv Longfeng , He Ting , Chen Tianji , Zang Mengdi , Zhong Liang , Wang Xinke , Shen Jingling , Hou Yanbing
Published: September 2015

An active all-optical high-efficiency broadband terahertz device based on an organometal halide perovskite (CH3NH3PbI3, MAPbI3)/inorganic (Si) structure is investigated. Spectrally broadband modulation of the THz transmission is obtained in the frequency range from 0.2 to 2.6 THz, and a modulation depth of nearly 100% can be achieved with a low-level photoexcitation power (∼0.4 W/cm2). Both THz transmission and reflection were suppressed in the MAPbI3/Si structure by an external continuous-wave (CW) laser. Enhancement of the charge carrier density at the MAPbI3/Si interface is crucial for photo-induced absorption. The results show that the proposed high-efficiency broadband optically controlled terahertz device based on the MAPbI3/Si structure has been realized.
A significant south-western range extension for the desert mouse (Pseudomys desertor) in Western Australia
Authors: Ellis R. J. , Spencer P. B. S. , Doody J. S. , Parkin T.
Published: September 2015

The desert mouse (Pseudomys desertor) is one of the most common and widespread native rodent species across arid and semiarid Australia. The species occurs in a variety of habitats and like many arid-zone rodents, its distribution and abundance is known to fluctuate with environmental conditions. Following the capture of a suspected specimen of P. desertor outside the current known range of the species, we used molecular-based methods to confirm the specimen’s identification as P. desertor. This note presents a record of the species north of Dalwallinu, Western Australia, which represents a significant range extension for the species of 324 km from the nearest confirmed record.
Using sedimentary diatoms to identify reference conditions and historical variability in shallow lake ecosystems in the Yangtze floodplain
Authors: Dong Xuhui , Yang Xiangdong , Chen Xu , Liu Qian , Yao Min , Wang Rong , Xu Min
Published: September 2015

The reference condition and historical variability of aquatic ecosystems are key ecological characters for understanding the dynamic and ecological assessment of wetland systems. Based on high-resolution chronological sequences of diatom records from 10 lakes in the Yangtze floodplain, this study aims to determine their ecological and chemical reference conditions, the historical variability and its controlling factors. Mesotrophic species Aulacoseria granulata, along with non-planktonic species Fragilaria spp., Navicula spp., Cocconeis placentula, Achnanthidium minutissimum, Cymbella spp. etc, were most abundant in the reference samples (1800–50). Accordingly, a relatively high chemical reference (50 µg L–1 in diatom-inferred total phosphorus concentration) was defined. The degree of floristic change comparing present with reference samples reveals that six of the 10 lakes have undergone significant ecological changes. The historical variability in those lakes was found to be regulated by the distance from the Yangtze River (negatively) and the lake catchment area (positively). This reflects the mechanism driving ecological change in floodplain lakes: the ecological conditions were sensitive to the nutrient input from the catchment and disturbance by the Yangtze River. This study demonstrates the robustness of palaeolimnological techniques in reconstructing the historical ecological characters of lake ecosystems, which may provide essential information for the management of wider types of wetland.
Dialogue in the stream of life
Authors: Weigand Edda
Published: September 2015

The paper considers dialogue from the point of view Wittgenstein has called ‘the stream of life’ and aims at describing analytically what happens in complex dialogues of performance. A short overview is given of approaches which use the term ‘communities’ to structure performance, e.g. ‘communities of practice’ or ‘speech communities’. Contrary to these approaches which are either oriented towards parts of the whole, such as speech, or address the whole only vaguely by terms of the social context, a genuinely holistic theory needs a solid constitutive basis which is considered to be the sequence of action and reaction in the complex whole of the action game. Language use means dialogic action. By analysing a complex authentic action game the methodology of such a holistic theory like the Mixed Game Model can be demonstrated in detail.
Disagreement and the speaker’s point of view
Authors: Colomina-Almiñana Juan J.
Published: September 2015

This article defends an intentionalist solution to cases of disagreement. Unlike conventionalist approaches, the paper shows that the truth-value of some sentences is shifted and relative to the concrete way the assertion is made. Unlike relativist accounts, it argues that cases of subjective meaning are just apparent, and really express normative content as included in embedded sentences. The paper advocates for a solution based on what I call the speaker’s point of view, which understands disagreement as expressing the speaker’s perspective in conversation about a particular matter without constraining the truth-value of the sentences of our natural language. Consequently, the speaker’s utterance is a speech act necessarily related to the interlocutor’s utterance, which is another speech act, since only by integrating the level of the communicative function into a dialogic interaction the real meaning of the utterances can completely show up.
Motives for Chinese script simplification
Authors: Pan Xiaxing , Jin Huiyuan , Liu Haitao
Published: September 2015

The Chinese script simplification movement originated from the debates about Chinese script (hànzì) in the late 19th and early 20th centuries. This movement was once the dominant part of language planning and language policy in China. The article describes the three major stages of Chinese script reform in the 20th century briefly, using Cooper’s ‘accounting scheme’ and its eight components as its organizing framework. In the case of Chinese script reform, two of the stages of the script reform movement — the first and third — failed, while the second was successful. In order to explain both the two failures and the success, this article focuses on the motives of the stages of the script reform movement. The discussions about the motives behind Chinese script reform in the literature generally focus on the contribution which the simplified hànzì has made to the improvement of China’s education; this article seeks to interpret the motives of the three stages of the script reform movement, rather, along the lines of the 7i model proposed by Ager. It concludes that there have been different motives present during different stages of the script reform movement, which in turn have had a powerful impact of the success or failure of particular reform efforts. Finally, it is suggested that the predominant trend in Chinese language planning and policy has now turned from script simplification to standardization.
The porous borders of language and nation
Authors: Zentz Lauren R.
Published: September 2015

This analysis of language use and legislation in globalization highlights challenges to and crossings of the borders of Indonesian nationalist ideologies and local language ecologies. Through the specific workings of language and languaging in situ, here explored through three brief examples of language use and ideologies in Central Java, I analyze university English majors’ discussions of the local meaningfulness of English. The analysis demonstrates that institutional language policies are simultaneously subverted by and influential in local language hierarchies. The discussions analyzed come from the students’ written Sociolinguistics class assignments while I was their teacher and from research interviews that they participated in with me, both in which I ask participants about the borders of what can be defined as the English language, and the borders of linguistic ideologies and nationalism in contemporary Indonesia. With an intent stemming from the very origins of language policy research to generate ideas for how state apparatuses might better serve their constituents (Fishman, 1974), this information is essential for understanding the limitations and opportunities that states are instrumental in creating among their citizenries.
The topic of planned languages (Esperanto) in the current specialist literature
Authors: Fiedler Sabine
Published: September 2015

Although planned languages such as Esperanto have achieved only limited success in their attempt to facilitate international communication so far, they have attracted considerable attention in discussions on the language question. This article examines how the topic is treated in recent publications on linguistics and language policy. The analysis reveals that researchers put forward a number of recurrent arguments for and against. Among arguments in favour of planned languages are their contribution to equal rights in international communication, their positive impact on the learning of other foreign languages, and their cost saving effects. Arguments against them include their bad image and limited communicative functions. Some researchers make predictions about the possible developments in the linguistic structure of Esperanto in the case of its official adoption, taking the development of ethnic languages as a point of departure. Esperanto’s Eurocentricity, its alleged isolation from culture, and the (non)existence of native speakers are among the features that are controversially discussed in the literature. Some conclusions for further interlinguistic research are drawn.
Gulf Cooperation Council (GCC), Qatar and dispute mediations: a critical investigation
Authors: Nuruzzaman Mohammed
Published: September 2015

This paper investigates the role played by the Gulf Cooperation Council (GCC) in mediating disputes since its creation in 1981 to 2011, the year of the outbreak of the ‘Arab Spring’. It analyzes the contributions of the GCC as a conflict mediator by cross-checking this sub-regional group’s institutional structure and policy approach, and presents two major findings. Firstly, the GCC was hardly designed as a conflict mediator, given that the Gulf Arab states created it as a vehicle to respond to intra-Gulf and external security threats and challenges. Secondly, in order to promote its foreign policy independence and boost its regional and global diplomatic profile to ensure its security and survival in the dangerous environment of the Gulf region, it is Qatar that has extensively attempted to mediate conflicts in Lebanon, Yemen and Sudan, with varying degrees of success, under the banners of the GCC and the Arab League. Finally, the paper presents a series of policy recommendations, based on critical insights from Qatari mediation experiences, to enable the GCC to be a proactive dispute mediator.
Proteasomal degradation of preemptive quality control (pQC) substrates is mediated by an AIRAPL–p97 complex
Authors: Braunstein Ilana , Zach Lolita , Allan Susanne , Kalies Kai-Uwe , Stanhill Ariel
Published: September 2015

The initial folding of secreted proteins occurs in the ER lumen, which contains specific chaperones and where posttranslational modifications may occur. Therefore lack of translocation, regardless of entry route or protein identity, is a highly toxic event, as the newly synthesized polypeptide is misfolded and can promiscuously interact with cytosolic factors. Mislocalized proteins bearing a signal sequence that did not successfully translocate through the translocon complex are subjected to a preemptive quality control (pQC) pathway and are degraded by the ubiquitin-proteasome system (UPS). In contrast to UPS-mediated, ER-associated degradation, few components involved in pQC have been identified. Here we demonstrate that on specific translocation inhibition, a p97–AIRAPL complex directly binds and regulates the efficient processing of polyubiquitinated pQC substrates by the UPS. We also demonstrate p97’s role in pQC processing of preproinsulin in cases of naturally occurring mutations within the signal sequence of insulin.
PTP1B-dependent regulation of receptor tyrosine kinase signaling by the actin-binding protein Mena
Authors: Hughes Shannon K. , Oudin Madeleine J. , Tadros Jenny , Neil Jason , Del Rosario Amanda , Joughin Brian A. , Ritsma Laila , Wyckoff Jeff , Vasile Eliza , Eddy Robert , Philippar Ulrike , Lussiez Alisha , Condeelis John S. , van Rheenen Jacco , White Forest , Lauffenburger Douglas A. , Gertler Frank B.
Published: September 2015

During breast cancer progression, alternative mRNA splicing produces functionally distinct isoforms of Mena, an actin regulator with roles in cell migration and metastasis. Aggressive tumor cell subpopulations express MenaINV, which promotes tumor cell invasion by potentiating EGF responses. However, the mechanism by which this occurs is unknown. Here we report that Mena associates constitutively with the tyrosine phosphatase PTP1B and mediates a novel negative feedback mechanism that attenuates receptor tyrosine kinase signaling. On EGF stimulation, complexes containing Mena and PTP1B are recruited to the EGFR, causing receptor dephosphorylation and leading to decreased motility responses. Mena also interacts with the 5′ inositol phosphatase SHIP2, which is important for the recruitment of the Mena-PTP1B complex to the EGFR. When MenaINV is expressed, PTP1B recruitment to the EGFR is impaired, providing a mechanism for growth factor sensitization to EGF, as well as HGF and IGF, and increased resistance to EGFR and Met inhibitors in signaling and motility assays. In sum, we demonstrate that Mena plays an important role in regulating growth factor–induced signaling. Disruption of this attenuation by MenaINV sensitizes tumor cells to low–growth factor concentrations, thereby increasing the migration and invasion responses that contribute to aggressive, malignant cell phenotypes.
Sorting nexin 9 differentiates ligand-activated Smad3 from Smad2 for nuclear import and transforming growth factor β signaling
Authors: Wilkes Mark C. , Repellin Claire E. , Kang Jeong-Han , Andrianifahanana Mahefatiana , Yin Xueqian , Leof Edward B.
Published: September 2015

Transforming growth factor β (TGFβ) is a pleiotropic protein secreted from essentially all cell types and primary tissues. While TGFβ’s actions reflect the activity of a number of signaling networks, the primary mediator of TGFβ responses are the Smad proteins. Following receptor activation, these cytoplasmic proteins form hetero-oligomeric complexes that translocate to the nucleus and affect gene transcription. Here, through biological, biochemical, and immunofluorescence approaches, sorting nexin 9 (SNX9) is identified as being required for Smad3-dependent responses. SNX9 interacts with phosphorylated (p) Smad3 independent of Smad2 or Smad4 and promotes more rapid nuclear delivery than that observed independent of ligand. Although SNX9 does not bind nucleoporins Nup153 or Nup214 or some β importins (Imp7 or Impβ), it mediates the association of pSmad3 with Imp8 and the nuclear membrane. This facilitates nuclear translocation of pSmad3 but not SNX9.
Modelling the effects of variation in reproductive traits on fish population resilience
Authors: Le Bris Arnault , Pershing Andrew J. , Hernandez Christina M. , Mills Katherine E. , Sherwood Graham D.
Published: September 2015

Preserving larger fish is often advocated as a conservation measure to help fish populations buffer environmental variation and fishing pressure. The rationale is that several size- and age-dependent reproductive traits confer a higher reproductive value to larger fish. The effects of variation in these reproductive traits on the dynamics of populations under various fishing patterns are however seldom evaluated. In this study, we develop a simulation model to evaluate how variation in three reproductive traits (fecundity–mass, hatching probability, and batch spawning) impacts the capacity of a fish population to withstand and recover from high fishing pressure. Biological functions of the model were calibrated based on the Gulf of Maine Atlantic cod stock, which is currently experiencing its lowest biomass level ever estimated. Results showed that variation in the shape of the fecundity–mass relationship had the most substantial impact on population resistance and recovery. Batch spawning and variation in hatching probability had limited impacts. Furthermore, results showed that preserving larger fish by imposing a slot fishery increased the resistance of the population to high fishing pressure, because it helped preserve the population reproductive potential determined by the high fecundity of large fish. The slot fishery, however, impeded population recovery, because it distributed the fishing pressure on intermediate-size classes which potential for biomass growth is maximal. This study underlines the importance of using precise size-dependent fecundity estimates when evaluating the productivity and sustainability of fisheries, as well as the importance of identifying priority among the components of population resilience (e.g. resistance or recovery) before implementing size-selective harvest strategies.