bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating wind turbine impacts on near-wake flow using profiling lidar data and large-eddy simulations with an actuator disk model
Authors: Mirocha Jeffrey D. , Rajewski Daniel A. , Marjanovic Nikola , Lundquist Julie K. , Kosović Branko , Draxl Caroline , Churchfield Matthew J.
Published: August 2015

Wind turbine impacts on the atmospheric flow are investigated using data from the Crop Wind Energy Experiment (CWEX-11) and large-eddy simulations (LESs) utilizing a generalized actuator disk (GAD) wind turbine model. CWEX-11 employed velocity-azimuth display (VAD) data from two Doppler lidar systems to sample vertical profiles of flow parameters across the rotor depth both upstream and in the wake of an operating 1.5 MW wind turbine. Lidar and surface observations obtained during four days of July 2011 are analyzed to characterize the turbine impacts on wind speed and flow variability, and to examine the sensitivity of these changes to atmospheric stability. Significant velocity deficits (VD) are observed at the downstream location during both convective and stable portions of four diurnal cycles, with large, sustained deficits occurring during stable conditions. Variances of the streamwise velocity component, σu, likewise show large increases downstream during both stable and unstable conditions, with stable conditions supporting sustained small increases of σu, while convective conditions featured both larger magnitudes and increased variability, due to the large coherent structures in the background flow. Two representative case studies, one stable and one convective, are simulated using LES with a GAD model at 6 m resolution to evaluate the compatibility of the simulation framework with validation using vertically profiling lidar data in the near wake region. Virtual lidars were employed to sample the simulated flow field in a manner consistent with the VAD technique. Simulations reasonably reproduced aggregated wake VD characteristics, albeit with smaller magnitudes than observed, while σu values in the wake are more significantly underestimated. The results illuminate the limitations of using a GAD in combination with coarse model resolution in the simulation of near wake physics, and validation thereof using VAD data.
Heat flux and plasma flow in the far scrape-off layer of the inboard poloidal field null configuration in QUEST
Authors: Onchi T. , Zushi H. , Mishra K. , Mahira Y. , Nagaoka K. , Hanada K. , Idei H. , Hasegawa M. , Nakamura K. , Fujisawa A. , Nagashima Y. , Matsuoka K. , Tashima S. , Banerjee S. , Kuzmin A. , Kawasaki S. , Nakashima H. , Higashijima A. , Watanabe O.
Published: August 2015

Heat flux and plasma flow in the scrape-off layer (SOL) are examined for the inboard poloidal field null (IPN) configuration of the spherical tokamak QUEST. In the plasma current (Ip) ramp-up phase, high heat flux (>1 MW/m2) and supersonic flow (Mach number M > 1) are found to be present simultaneously in the far-SOL. The heat flux is generated by energetic electrons excursed from the last closed flux surface. Supersonic flows in the poloidal and toroidal directions are correlated with each other. In the quasi-steady state, sawtooth-like oscillation of Ip at 20 Hz is observed. Heat flux and subsonic plasma flow in the far-SOL are modified corresponding to the Ip-oscillation. The heat flow caused by motion of energetic electrons and the bulk-particle transport to the far-SOL is enhanced during the low-Ip phase. Modification of plasma flow in the far SOL occurs earlier than the Ip crash. The M–Ip curve has a limit-cycle characteristic with sawtooth-like oscillation. Such a core–SOL relationship indicates that the far-SOL flow plays an important role in sustaining the oscillation of Ip in the IPN configuration.
Correlation between vibrational temperature of N2 and plasma parameters in inductively coupled Ar/N2 plasmas
Authors: Kim Young-Cheol , Lee Hyo-Chang , Kim Yu-Sin , Chung Chin-Wook
Published: August 2015

Vibrational temperature (Tvib) of N2 gas and electron energy distribution function (EEDF) were measured in Ar/N2 mixture inductively coupled plasma (ICP). At a low gas pressure of 5 mTorr where the EEDF is bi-Maxwellian distribution, plasma density np and Tvib (from 7000 K to 5600 K) slightly decrease. However, remarkable decrease in np and Tvib is found with the dilution of N2 gas at a high gas pressure of 50 mTorr, where the EEDF is depleted Maxwellian distribution at a fixed ICP power of 150 W. When the ICP power increases from 150 W to 300 W at the gas pressure of 50 mTorr, the depleted tail on the EEDF is replenished, while np is little changed with the dilution of N2 gas. In this case, Tvib slightly decreases from 9500 K to 7600 K. These results indicate that the variation of Tvib is strongly correlated to the plasma parameters, such as the plasma density and EEDF.
L
2-stability of the Landau equation near global Maxwellians
Authors: Ha Seung-Yeal , Xiao Qinghua
Published: August 2015

We present an L2-stability of the kinetic Landau equation for a single species charged plasma with an inverse power-law interaction force in the perturbative regime of global Maxwellians. Our result demonstrates that the L2-distance between two classical solutions to the Landau equation can be controlled by that between corresponding initial data in a Lipschitz manner. The Coulomb interaction is known to be the singular and marginal case of the theory of the Boltzmann equation where the grazing collisions are the dominant. For some class of classical solutions, we show that our L2-stability result can provide a uniform L2-stability.
Cosmic ray confinement and transport models for probing their putative sources
Authors: Malkov M. A.
Published: August 2015

Recent efforts in cosmic ray (CR) confinement and transport theory are discussed. Three problems are addressed as being crucial for understanding the present day observations and their possible telltale signs of the CR origin. The first problem concerns CR behavior right after their release from a source, such as a supernova remnant. At this phase, the CRs are confined near the source by self-emitted Alfven waves. The second is the problem of diffusive propagation of CRs through the turbulent interstellar medium. This is a seemingly straightforward and long-resolved problem, but it remains controversial and reveals paradoxes. A resolution based on the Chapman-Enskog asymptotic CR transport analysis, that also includes magnetic focusing, is suggested. The third problem is about a puzzling sharp (∼10°) anisotropies in the CR arrival directions that might bear on important clues of their transport between the source and observer. The overarching goal is to improve our understanding of all aspects of the CR's source escape and ensuing propagation through the galaxy to the level at which their sources can be identified observationally.
Improving intermolecular interactions in DFTB3 using extended polarization from chemical-potential equalization
Authors: Christensen Anders S. , Elstner Marcus , Cui Qiang
Published: August 2015

Semi-empirical quantum mechanical methods traditionally expand the electron density in a minimal, valence-only electron basis set. The minimal-basis approximation causes molecular polarization to be underestimated, and hence intermolecular interaction energies are also underestimated, especially for intermolecular interactions involving charged species. In this work, the third-order self-consistent charge density functional tight-binding method (DFTB3) is augmented with an auxiliary response density using the chemical-potential equalization (CPE) method and an empirical dispersion correction (D3). The parameters in the CPE and D3 models are fitted to high-level CCSD(T) reference interaction energies for a broad range of chemical species, as well as dipole moments calculated at the DFT level; the impact of including polarizabilities of molecules in the parameterization is also considered. Parameters for the elements H, C, N, O, and S are presented. The Root Mean Square Deviation (RMSD) interaction energy is improved from 6.07 kcal/mol to 1.49 kcal/mol for interactions with one charged species, whereas the RMSD is improved from 5.60 kcal/mol to 1.73 for a set of 9 salt bridges, compared to uncorrected DFTB3. For large water clusters and complexes that are dominated by dispersion interactions, the already satisfactory performance of the DFTB3-D3 model is retained; polarizabilities of neutral molecules are also notably improved. Overall, the CPE extension of DFTB3-D3 provides a more balanced description of different types of non-covalent interactions than Neglect of Diatomic Differential Overlap type of semi-empirical methods (e.g., PM6-D3H4) and PBE-D3 with modest basis sets.
A computational study of an atomizing liquid sheet
Authors: Deshpande Suraj S. , Gurjar Soumil R. , Trujillo Mario F.
Published: August 2015

Linear instability predictions of liquid sheets injected into a gas medium are well established in the literature. These analyses are often used in Lagrangian-Eulerian spray simulations, a prominent simulation method, to model the dynamics occurring in the near-nozzle region. In the present work, these instability predictions are re-examined by first generalizing the treatment of interfacial conditions and related assumptions with a two-phase Orr-Sommerfeld (OS) system, and second, by employing highly resolved-Volume-of-Fluid (VoF) simulations. After presenting some validation exercises for both the VoF and OS solvers, the OS predictions are compared to earlier studies from the literature leading to reasonable agreement in the limit as the boundary layer thickness tends to zero. Results from VoF simulations of liquid sheet injection are used to characterize the range of scales of the liquid structures immediately before atomization. The mean value in this range is found to be approximately two to three orders of magnitude larger than the corresponding predictions from previous studies. A two-phase mixing layer under the same physical conditions is used to examine this disparity, revealing that within the linear regime, relatively good agreement exists between the VoF and OS predicted instability mechanisms. However, the most unstable mode in the linear regime is too small to cause a fracture or atomization of the liquid sheet and hence cannot be directly responsible for the atomization. The generation of a much larger mode, which emerges well beyond the linear regime, is the one causing breakup.
Strong piezoelectric anisotropy d15/d33 in ⟨111⟩ textured Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 ceramics
Authors: Yan Yongke , Priya Shashank
Published: August 2015

The shear mode piezoelectric properties of Pb(Mg1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMN-PZT) ceramic with 72% ⟨111⟩ texture were investigated. The piezoelectric anisotropic factor d15/d33 was as high as 8.5 in ⟨111⟩ textured ceramic as compared to 2.0 in random counterpart. The high d15/d33 indicates the “rotator” ferroelectric characteristics of PMN-PZT system and suggests that the large shear piezoelectric response contributes towards the high longitudinal piezoelectric response (d33) in non-polar direction (d33 = 1100 pC/N in ⟨001⟩ textured ceramic vs. d33 = 112 pC/N in ⟨111⟩ textured ceramic).
Proton disorder in cubic ice: Effect on the electronic and optical properties
Authors: Garbuio Viviana , Cascella Michele , Kupchak Igor , Pulci Olivia , Seitsonen Ari Paavo
Published: August 2015

The proton disorder in ice has a key role in several properties such as the growth mode, thermodynamical properties, and ferroelectricity. While structural phase transitions from proton disordered to proton ordered ices have been extensively studied, much less is known about their electronic and optical properties. Here, we present ab initio many body perturbation theory-based calculations of the electronic and optical properties of cubic ice at different levels of proton disorder. We compare our results with those from liquid water, that acts as an example of a fully (proton- and oxygen-)disordered system. We find that by increasing the proton disorder, a shrinking of the electronic gap occurs in ice, and it is smallest in the liquid water. Simultaneously, the excitonic binding energy decreases, so that the final optical gaps result to be almost independent on the degree of proton disorder. We explain these findings as an interplay between the local dipolar disorder and the electronic correlation.
Magneto-electronic coupling in modulated defect-structures of natural Fe1−xS
Authors: Charilaou M. , Kind J. , Koulialias D. , Weidler P. G. , Mensing C. , Löffler J. F. , Gehring A. U.
Published: August 2015

We provide compelling experimental evidence that the low-temperature transition in natural non-stoichiometric Fe7S8, a major magnetic remanence carrier in the Earth's crust and in extraterrestrial materials, is a phenomenon caused by magnetic coupling between epitaxially intergrown superstructures. The two superstructures differ in their defect distribution, and consequently in their magnetic anisotropy. At T < 30 K, the magnetic moments of the superstructures become strongly coupled, resulting in a 12-fold anisotropy symmetry, which is reflected in the anisotropic magneto-resistance.
Modified Heisenberg model for the zig-zag structure in multiferroic RMn2O5
Authors: Bahoosh Safa Golrokh , Wesselinowa Julia M. , Trimper Steffen
Published: August 2015

The class of RMn2O5 (R = Ho, Tb, Y, Eu) compounds offers multiferroic properties where the refined magnetic zig-zag order breaks the inversion symmetry. Varying the temperature, the system undergoes a magnetic and a subsequent ferroelectric phase transition where the ferroelectricity is magnetically induced. We propose a modified anisotropic Heisenberg model that can be used as a tractable analytical model studying the properties of those antiferromagnetic zig-zag spin chains. Based on a finite temperature Green's function method, it is shown that the polarization is induced solely by different exchange couplings of the two different Mn4+ and Mn3+ magnetic ions. We calculate the excitation energy of the spin system for finite temperatures, which for its part determines the temperature dependent magnetization and polarization. The ferroelectric phase transition is manifested as a kink in the excitation energy. The variation of the polarization by an external magnetic field depends strongly on the direction of that field. Whereas, the polarization in b-direction increases with an external magnetic field as well in b-direction it can be switched for strong fields in a-direction. The results based on that modified Heisenberg model are in qualitative agreement with experimental data.
Impact of La2O3 interfacial layers on InGaAs metal-oxide-semiconductor interface properties in Al2O3/La2O3/InGaAs gate stacks deposited by atomic-layer-deposition
Authors: Chang C.-Y. , Ichikawa O. , Osada T. , Hata M. , Yamada H. , Takenaka M. , Takagi S.
Published: August 2015

We examine the electrical properties of atomic layer deposition (ALD) La2O3/InGaAs and Al2O3/La2O3/InGaAs metal-oxide-semiconductor (MOS) capacitors. It is found that the thick ALD La2O3/InGaAs interface provides low interface state density (Dit) with the minimum value of ∼3 × 1011 cm−2 eV−1, which is attributable to the excellent La2O3 passivation effect for InGaAs surfaces. It is observed, on the other hand, that there are a large amount of slow traps and border traps in La2O3. In order to simultaneously satisfy low Dit and small hysteresis, the effectiveness of Al2O3/La2O3/InGaAs gate stacks with ultrathin La2O3 interfacial layers is in addition evaluated. The reduction of the La2O3 thickness to 0.4 nm in Al2O3/La2O3/InGaAs gate stacks leads to the decrease in hysteresis. On the other hand, Dit of the Al2O3/La2O3/InGaAs interfaces becomes higher than that of the La2O3/InGaAs ones, attributable to the diffusion of Al2O3 through La2O3 into InGaAs and resulting modification of the La2O3/InGaAs interface structure. As a result of the effective passivation effect of La2O3 on InGaAs, however, the Al2O3/10 cycle (0.4 nm) La2O3/InGaAs gate stacks can realize still lower Dit with maintaining small hysteresis and low leakage current than the conventional Al2O3/InGaAs MOS interfaces.
Modeling and simulation of communication networks for use in integrating high wind power generation into a power grid
Authors: Ahmed Mohamed A. , Kang Yong Cheol , Kim Young-Chon
Published: August 2015

As wind energy is further integrated into the power grid, real-time monitoring and control of wind power farms (WPFs) will become more difficult. The large amount of data that are generated from the WPFs will increase the burden on communication networks. In order to combat these problems, it is indispensable to develop a reliable communication network capable of managing large amounts of information. This paper addresses a framework to design communication networks for integrating high level of wind power generation into the grid. The proposed network has a hierarchical architecture consisting of three levels: WPFs, local control centers, and a central control center. The network modeling and simulation are conducted to evaluate the performance of the hierarchical network architecture with various link capacities. As a case study, real WPFs in Jeju Island, South Korea, are modeled and simulated under various network scenarios using the optimized network engineering tool. The simulation results were analyzed and compared with respect to the end-to-end delay for different services.
Multilayer-WS2:ferroelectric composite for ultrafast tunable metamaterial-induced transparency applications
Authors: Yang Xiaoyu , Yang Jinghuan , Hu Xiaoyong , Zhu Yu , Yang Hong , Gong Qihuang
Published: August 2015

An ultrafast and low-power all-optical tunable metamaterial-induced transparency is realized, using polycrystalline barium titanate doped gold nanoparticles and multilayer tungsten disulfide microsheets as nonlinear optical materials. Large nonlinearity enhancement is obtained associated with quantum confinement effect, local-field effect, and reinforced interaction between light and multilayer tungsten disulfide. Low threshold pump intensity of 20 MW/cm2 is achieved. An ultrafast response time of 85 ps is maintained because of fast carrier relaxation dynamics in nanoscale crystal grains of polycrystalline barium titanate. This may be useful for the study of integrated photonic devices based on two-dimensional materials.
Vibrational energy levels of the simplest Criegee intermediate (CH2OO) from full-dimensional Lanczos, MCTDH, and MULTIMODE calculations
Authors: Yu Hua-Gen , Ndengue Steve , Li Jun , Dawes Richard , Guo Hua
Published: August 2015

Accurate vibrational energy levels of the simplest Criegee intermediate (CH2OO) were determined on a recently developed ab initio based nine-dimensional potential energy surface using three quantum mechanical methods. The first is the iterative Lanczos method using a conventional basis expansion with an exact Hamiltonian. The second and more efficient method is the multi-configurational time-dependent Hartree (MCTDH) method in which the potential energy surface is refit to conform to the sums-of-products requirement of MCTDH. Finally, the energy levels were computed with a vibrational self-consistent field/virtual configuration interaction method in MULTIMODE. The low-lying levels obtained from the three methods are found to be within a few wave numbers of each other, although some larger discrepancies exist at higher levels. The calculated vibrational levels are very well represented by an anharmonic effective Hamiltonian.
Note: Fabrication of resolution target for super-resolution microscopy
Authors: Iketaki Y. , Oi H. , Bokor N. , Kumagai H.
Published: August 2015

We fabricated a resolution target for super-resolution microscopes (SRMs). The target was constructed by scattering a dyed photo-resist on a glass cover plate and used UV nano-imprinting to transfer minute line-and-space patterns on to the photo-resist layer. Using this resolution target, an image obtained from a SRM and its properties was evaluated quantitatively.
Galvanism of continuous ionic liquid flow over graphene grids
Authors: He Yijia , Lao Junchao , Yang Tingting , Li Xiao , Zang Xiaobei , Li Xinming , Zhu Miao , Chen Qiao , Zhong Minlin , Zhu Hongwei
Published: August 2015

Flow-induced voltage generation on graphene has attracted great attention, but harvesting voltage by ionic liquid continuously flowing along graphene at macro-scale is still a challenge. In this work, we design a network structure of graphene grids (GG) woven by crisscrossed graphene micron-ribbons. The structure is effective in splitting the continuous fluid into “droplets” to generate consistent voltage using the mechanism of electrochemical energy generation. Key parameters such as flow rate, mesh number of GG, and slope angle are optimized to obtain maximum voltage in energy generation. The results suggest great potential of this graphene-based generator for future applications in energy harvesting.
In-situ x-ray studies of compositional control during synthesis of LaGaO3 by radio frequency-magnetron sputtering
Authors: Highland Matthew J. , Fong Dillon D. , Ju Guangxu , Thompson Carol , Baldo Peter M. , Fuoss Paul H. , Eastman Jeffrey A.
Published: August 2015

In-situ synchrotron x-ray scattering has been used to monitor and control the synthesis of LaGaO3 epitaxial thin films by 90° off-axis RF-magnetron sputtering. Films deposited from a single LaGaO3 source were compared with those prepared by alternating deposition from separate La2O3 and Ga2O3 sources. The conditions for growth of stoichiometric films were determined by real-time monitoring of secondary phase formation as well as from features in the diffuse scatter from island formation during synthesis. These results provide atomic-scale insight into the mechanisms taking place during reactive epitaxial growth and demonstrate how in-situ techniques can be utilized to achieve stoichiometric control in ultrathin films.
Note: An improved calibration system with phase correction for electronic transformers with digital output
Authors: Cheng Han-miao , Li Hong-bin
Published: August 2015

The existing electronic transformer calibration systems employing data acquisition cards cannot satisfy some practical applications, because the calibration systems have phase measurement errors when they work in the mode of receiving external synchronization signals. This paper proposes an improved calibration system scheme with phase correction to improve the phase measurement accuracy. We employ NI PCI-4474 to design a calibration system, and the system has the potential to receive external synchronization signals and reach extremely high accuracy classes. Accuracy verification has been carried out in the China Electric Power Research Institute, and results demonstrate that the system surpasses the accuracy class 0.05. Furthermore, this system has been used to test the harmonics measurement accuracy of all-fiber optical current transformers. In the same process, we have used an existing calibration system, and a comparison of the test results is presented. The system after improvement is suitable for the intended applications.
Relaxation dynamics of surface-adsorbed water molecules in nanoporous silica probed by terahertz spectroscopy
Authors: Huang Yu-Ru , Liu Kao-Hsiang , Mou Chung-Yuan , Sun Chi-Kuang
Published: August 2015

Relaxation dynamics of an exclusively adsorbed water molecule in mesoporous silica MCM-41-S was studied by using terahertz spectroscopy. With the temperature controlled from 0 to 50 °C, we observed strongly frequency- and temperature-dependent dielectric relaxation responses, implying that, unlike ice, surface-adsorbed water molecules retained flourishing picosecond dynamics. Based on the Debye relaxation model, a relaxation time constant was found to increase from 1.77 to 4.83 ps when the water molecule was cooled from 50 to 0 °C. An activation energy of ∼15 kJ/mol, which was in close agreement with a hydrogen-bonding energy, was further extracted from the Arrhenius analysis. Combined with previous molecular dynamics simulations, our results indicate that the reorientation relaxation originated from the “flip-flop” rotation of a three hydrogen-bonded surface-adsorbed water molecule.
Micro-photoluminescence and micro-Raman investigations of rolled-up InGaAs/GaAs microtubes monolithically integrated on silicon
Authors: Wang Qi , Gao Yunxia , Mao Guoming , Liu Hao , Ren Xiaomin
Published: August 2015

Free-standing InGaAs/GaAs microtubes have been monolithically integrated on Si platform by self-rolling of a metamorphic InGaAs/GaAs bilayer. Micro-photoluminescence (μ-PL) spectroscopy features that PL peak from Si-based InGaAs/GaAs microtubes is remarkably enhanced in intensity, slightly redshifted in position, and narrowed in full width at half maximum as compared with Si-based as-grown region. Raman spectroscopy manifests that Raman peaks for microtube on Si have smaller wavenumbers than those on GaAs, also detects the obvious blueshift of GaAs longitudinal-optical phonon frequency on microtube with respect to that of their as-grown counterparts.
SiSn diodes: Theoretical analysis and experimental verification
Authors: Hussain Aftab M. , Wehbe Nimer , Hussain Muhammad M.
Published: August 2015

We report a theoretical analysis and experimental verification of change in band gap of silicon lattice due to the incorporation of tin (Sn). We formed SiSn ultra-thin film on the top surface of a 4 in. silicon wafer using thermal diffusion of Sn. We report a reduction of 0.1 V in the average built-in potential, and a reduction of 0.2 V in the average reverse bias breakdown voltage, as measured across the substrate. These reductions indicate that the band gap of the silicon lattice has been reduced due to the incorporation of Sn, as expected from the theoretical analysis. We report the experimentally calculated band gap of SiSn to be 1.11 ± 0.09 eV. This low-cost, CMOS compatible, and scalable process offers a unique opportunity to tune the band gap of silicon for specific applications.
Gigawatt-class radiation generated by a Ka-band overmoded Cherenkov-type high power millimeter wave generator
Authors: Wu Dapeng , Shu Ting , Ju Jinchuan , Peng Shengren
Published: August 2015

Particle simulation and experimental results are presented about a Ka-band overmoded Cherenkov-type high power millimeter wave generator in this paper. The relativistic electron beam with peak current of 8.4 kA was generated by a pulsed power accelerator working at the voltage of 625 kV, which was guided by an axial magnetic field of 1.05 T and transported through the beam-wave interaction structures. After careful calibration, the microwave power radiated in the far field was as high as about 500 MW, with a frequency of 32.1 GHz and a pulse width of 20 ns. The radiation mode was well controlled to be TM0n mode.
Enhancing photocatalysis in SrTiO3 by using Ag nanoparticles: A two-step excitation model for surface plasmon-enhanced photocatalysis
Authors: Ma Lei , Sun Tao , Cai Hua , Zhou Zhi-Quan , Sun Jian , Lu Ming
Published: August 2015

Surface plasmon (SP)-enhanced ultraviolet and visible photocatalytic activities of SrTiO3 (STO) are observed after incorporating Ag nanoparticles (Ag-NPs) on STO surfaces. A two-step excitation model is proposed to explain the SP-enhanced photocatalysis. The point of the model is that an electron at the valence band of STO is first excited onto the Fermi level of Ag-NP by the SP field generated on the Ag-NP, and then injected into the conduction band of STO from the SP band, leaving a hole at the valence band of STO. A full redox catalytic reaction at the surface of STO is then available. For Ag-NP incorporated STO, up-converted and inter-band photoluminescence emissions of STO are observed, and nonlinear evolutions of photocatalytic activity with illumination light powers are found. Furthermore, near infrared photocatalysis is detected. These results support the proposed model.
Total Radiosynthesis: Thinking Outside ‘the Box'
Authors: Liang Steven H. , Vasdev Neil
Published: August 2015

The logic of total synthesis transformed a stagnant state of chemistry when there was a paucity of methods and reagents to synthesize pharmaceuticals. Molecular imaging by positron emission tomography (PET) is now experiencing a renaissance in the way radiopharmaceuticals are synthesized; however, a paradigm shift is desperately needed in the radiotracer discovery pipeline to accelerate drug development. As with most drugs, most radiotracers also fail, therefore expeditious evaluation of tracers in preclinical models before optimization or derivatization of the lead molecules is necessary. Furthermore the exact position of the 11C and 18F radionuclide in tracers is often critical for metabolic considerations, and flexible methodologies to introduce radionuclides are needed. A challenge in PET radiochemistry is the limited choice of labelled building blocks available with carbon-11 (11C; half-life ~20 min) and fluorine-18 (18F; half-life ~2 h). In fact, most drugs cannot be labelled with 11C or 18F owing to a lack of efficient and diverse radiosynthetic methods. Routine radiopharmaceutical production generally relies on the incorporation of the isotope at the last or penultimate step of synthesis. Such reactions are conducted within the constraints of an automated synthesis unit (‘box’), which has further stifled the exploration of multistep reactions with short-lived radionuclides. Radiopharmaceutical synthesis can be transformed by considering logic of total synthesis to develop novel approaches for 11C- and 18F-radiolabelling complex molecules via retrosynthetic analysis and multistep reactions. As a result of such exploration, new methods, reagents, and radiopharmaceuticals for in vivo imaging studies are discovered and are critical to work towards our ultimate, albeit impossible goal – a concept we term as total radiosynthesis – to radiolabel virtually any molecule. In this account, we show how multistep radiochemical reactions have impacted our radiochemistry program, with prominent examples from others, focusing on impact towards human imaging studies. As the goal of total synthesis is to be concise, we strive to simplify the syntheses of radiopharmaceuticals. New clinically useful strategies, including [11C]CO2 fixation, which has enabled library radiosynthesis, as well as radiofluorination of non-activated arenes via iodonium ylides are highlighted. We also showcase state-of-the-art automation technologies, including microfluidic flow chemistry for radiopharmaceutical production.
Microscleres and gemmoscleres as phylogenetic signals in Spongillida: phylogeny and biogeography of the genus Metania Gray, 1867 (Porifera, Metaniidae)
Authors: Castello-Branco Cristiana , Calor Adolfo Ricardo , Menegola Carla
Published: August 2015

The genus Metania comprises 11 species of freshwater sponge that are distributed circumtropically: five are Neotropical, three Afrotropical, two Oriental and one Australian. Here we infer the phylogeny of the genus Metania and examine the processes that lead to the current biogeographic distribution using cladistic analysis. One matrix with 26 morphological characters was analysed using the TNT software, and resulted in two most parsimonious cladograms (strict consensus). Our results support monophyly of Metania due to two characters unique to the genus: presence of acanthoxeas and presence of spines in the shaft of the gemmoscleres. Also, the genera Drulia and Houssayella were synonymised with Metania. The family Metaniidae – allocated in the recently proposed order Spongillida – now contains three genera: Acalle Gray, 1867, Metania Gray, 1867 and Corvomeyenia Weltner, 1913. Brooks parsimony analysis of Metania resulted in a single area cladogram showing a Gondwanan pattern: (Neartic (Australian (Oriental (Afrotropical, Neotropical)))) and thus the current distribution is explained by the breakup of Gondwana.
Phylogenetic reconstruction of scleraxonian octocorals supports the resurrection of the family Spongiodermidae (Cnidaria, Alcyonacea)
Authors: Cairns Stephen D. , Wirshing Herman H.
Published: August 2015

The Scleraxonia are a group of octocorals that share similarities of their axis morphology. However, molecular phylogenetic analyses have shown this group to be largely polyphyletic. As a result, there is a significant lack of understanding of what constitutes distinct evolutionary units among members of this group, particularly at the family level. Prompted by the discovery of an unknown spongiodermid scleraxonian octocoral (Anthothelidae) from shallow water off the Pacific coast of lower Baja California, a phylogenetic analysis of the undescribed specimen, together with members of six scleraxonian families and an additional 29 non-scleraxonian octocorallian families was performed. Two mitochondrial loci (mtMutS and COI) and one nuclear locus (28S) supported a monophyletic spongiodermid clade (Homophyton, Callipodium, Diodogorgia, Titanideum and Sclerophyton, gen. nov.) at the family-level. The unknown scleraxonian was supported as a new genus and species within the spongiodermid clade, sister to the western Atlantic genus Titanideum. A morphological examination of the taxa within this clade revealed shared morphological similarities in solenial (boundary) canals, and medullar and cortical sclerites. A revision, with illustrations, of the Spongiodermidae was performed. Similar to previous studies, this study underscores the importance of combined morphological and molecular analyses in order to resolve unstable systematic relationships among octocorals.
Determining light verb constructions in contemporary British and Irish English
Authors: Ronan Patricia , Schneider Gerold
Published: August 2015

This study implements an automated parser-based approach to the investigation of light verb constructions. The database consisting of ICE-GB and ICE-IRE is used to obtain qualitative and quantitative results on the use of light verb structures. The study explains and evaluates the steps employed to optimize parser output in detecting open lists of light verb constructions. It discusses the qualitative usage differences of these structures in the data between the two varieties and finds that ICE-GB favours fewer high frequency light verbs while ICE-IRE contains more diverse lower frequency light verbs and more passives. Overall, counts of light verb constructions are considerably higher than previously assumed. The projected counts suggest that attestations of light verb constructions will increase considerably if the search is not restricted to certain high-frequency light verbs as is typically done in studies employing manual or semi-automatic approaches to data collection.
Repetition in John Irving’s novelA Widow for One Year
Authors: Čermáková Anna
Published: August 2015

The present study applies some of the approaches used in corpus stylistics to examine repetition in John Irving’s novelA Widow for One Yearand its translations into Czech and Finnish. The main aim of this case study is to explore whether systematic identification of repetitive textual features in a source language may be a beneficial procedure for translators of literary texts. The underlying assumption is that, in their complexity, not all repetitive features are necessarily easily noticeable. Repetitiveness here is identified with cluster and keyword analysis that are subsequently considered in synergy. Relevant translation solutions are examined. Though repetition plays a central role in the novel, translators show a marked stylistic strategy to avoid them. The results of the study suggest that application of corpus tools may help translators to uncover the structure of the text and keep their translation consistent.
Towards coherent infinitival patterns in the history of German
Authors: Demske Ulrike
Published: August 2015

According to Haider (2010), we have to distinguish three types of infinitival complements in Present-Day German: (i) CP complements, (ii) VP complements and (iii) verbal clusters. While CP complements give rise to biclausal structures, VP complements and verbal clusters indicate a monoclausal structure. Non-finite verbs in verbal clusters build a syntactic unit with the governing verb. It is only the last infinitival pattern that we address as a so-called coherent infinitival pattern, a notion introduced in the influential work of Bech (1955/57). Verbal clusters are bound to languages with an OV grammar, hence the well-known differences regarding infinitival syntax in German and English (Haider 2003, Bobaljik 2004). On the widespread assumption that German has been an OV language throughout its history (Axel 2007), we expect all three types of infinitival complements to be present from the earliest attestions of German.

This expectation, however, is not borne out. In the present article, I show that we find infinitival complements projecting either CPs or VPs in older stages of German, while verbal clusters turn out to be a quite recent phenomenon in the history of German, as already suggested in work by Askedal (1998), Demske (2008) and Maché & Abraham (2011). In line with current beliefs that German is underspecified regarding the direction of government in earlier stages of its historical development, I argue that the rise of verbal clusters is motivated by the increasing stabilization of an OV grammar since the 16th century.
AcI and control infinitives: How different are they?
Authors: Speyer Augustin
Published: August 2015

In German, there are two infinitive constructions for complement infinitives, theaccusativus cum infinitivo(AcI) and theobject control infinitive construction(OCIC). Both constructions have nearly identical structures, where the logical subject of the infinitive is a distinct constituent from the rest of the infinitival clause, although in Modern German they show differences in form: the AcI is coherent and governs the bare infinitive, while the OCIC is incoherent and governs thezu-infinitive. It can be shown that these differences only developed over time and are reflexes of semantic differences between the constructions rather than of structural differences. Superficial binding differences that suggest a structural difference follow instead from the structures of the involved verb phrases.
On the loss of copy-raising and the development of infinitive complements
Authors: Jędrzejowski Łukasz
Published: August 2015

This article deals with (non‑)finite complement clauses embedded under the inceptive phase predicatebeginnen‘begin’ in the history of German and illustrates how infinitives replaced finite clauses headed by the complementizerdass‘that’. The main objective is to show that it was possible in Old High German (750–1050) to raise the subject from the embedded clause into the matrix subject position, crossing a CP boundary and leaving a pronominal copy in the dependent clause (copy-raising). Moreover, it is claimed thatbeginnenin its function as a subject control verb instantiates a recent development in the history of German and that this use developed out of a raising structure.
Infinitival complementation from Caucasian Albanian to Modern Udi
Authors: Ganenkov Dmitry
Published: August 2015

The article investigates diachronic changes in infinitival complementation from Caucasian Albanian to modern Udi dialects. It describes the syntactic structure of infinitival complements in Caucasian Albanian, 19th century Vartashen Udi and two modern dialects, and concentrates on case marking of overt subjects in constructions with the matrix verbs ‘can, be able’, ‘begin’ and ‘want’. From a diachronic point of view, the data presented in the article allow us to conclude that historical changes in both the lexical form of complement-taking predicates and the morphology of their complements obey Cristofaro’s (2003) Complement Deranking Hierarchy.
The decline of non-finiteness as a syntactic mechanism for embedding in East Slavic
Authors: Madariaga Nerea
Published: August 2015

This article focuses on how and why non-finite structures weakened as a productive device for embedding in East Slavic and became replaced by an alternative system of finite CPs in many syntactic contexts. The relevant structures analyzed here are infinitive clauses and participial (absolute) constructions. Both constructions were available in almost any embedded context in early Slavic (Old Church Slavonic and Old Russian). However, in later stages (Middle Russian and Modern Russian) embedded infinitive constructions became severely restricted, while absolute constructions disappeared altogether. In order to account for this change, I review a series of conditions that preceded the decline process analyzed here and propose a final trigger for the emergence of a new system of non-finiteness in modern Russian; namely, I explore the possibility that the change in the pro-drop character of Russian turned embedded infinitive clauses into Obligatory Control structures, and forced every other non-finite structure to be replaced by an alternative (finite) embedding device.
What the present can tell us about the future
Authors: Edmonds Amanda , Gudmestad Aarnes
Published: August 2015

This investigation studies the second language (L2) development of variable future-time expression in French. One hundred and eighteen nonnative speakers at four proficiency levels and 30 native speakers completed a written-contextualized task (WCT), a language-proficiency test and a background questionnaire. The verb form (inflectional future, periphrastic future, and present) selected for each item on the WCT was coded for three independent linguistic factors: presence of a lexical temporal indicator, temporal distance and (un)certainty. Multinomial logistic regression tests and a follow-up analysis of high and low frequency of the present demonstrated that this form plays a complex role in native-speaker variability and is acquired late in contexts of future-time reference for nonnative speakers.
Subjunctive use and development in L2 French
Authors: McManus Kevin , Mitchell Rosamond
Published: August 2015

We investigated the use and development of the Subjunctive in L2 French. Participants were 29 students of French at a UK university, who additionally spent nine months in France, and ten native speakers of French. Data were collected from two production tasks (oral and written) and a grammaticality judgement task. The results show that all participants made some use of the Subjunctive before leaving for France, with only limited development in its use during their stay. It is more frequently used in writing than in speech, consistent with French corpus-based research (O’Connor DiVito 1997). The judgement findings reveal significant differences between different Subjunctive triggers, with learners consistently better able to recognise affirmative triggers over conjunctions and negatives. Overall, it appears that affirmative Subjunctive triggers represent a key source of development, with most change evident for lower proficiency learners.
Effects of corrective feedback on L2 acquisition of tense-aspect verbal morphology
Authors: Mifka-Profozic Nadia
Published: August 2015

In this study, the effectiveness of implicit corrective feedback was examined with a group of 30 sixteen-year-old English native speakers learning French, who received either recasts or clarification requests on errors they made with the passé composé and the imparfait. The control group did not receive any feedback. Overall, the results indicate that recasts were more effective in improving accuracy of form and use for both the passé composé and the imparfait. However, an examination of language development with reference to the Aspect Hypothesis and the inherent lexical aspect of verbs showed that no change occurred between the pretest and the posttests. The passé composé was associated exclusively with achievement verbs, whereas the imparfait was limited to several frequent irregular stative verbs and a few activity verbs.
Energy self-sufficient sustainable integrated farming systems for livelihood security under a changing climate scenario in an Indian context: a case-study approach.
Authors: Behera U. K. , Amjath Babu Amjath Babu , Kaechele H. , France J.
Published: August 2015

The farming systems of the world have to meet multiple demands, e.g. supporting livelihood, conserving biodiversity, off-setting emissions and adapting to climate change. As a traditional way of farming in India, an integrated farming system (IFS) represents multiple crops (cereals, legumes, tree crops, vegetables, etc.) and multiple enterprises (livestock production, fish farming, bee keeping, etc.) on a single farm. Taking a case-study approach, we analyse the economics, calculate energy balances and describe the resource flows within such an integrated farm. Additionally, the concept of an IFS that makes these farms energy self-sufficient (or even in surplus), especially in modern forms of energy, is discussed. We argue for integrating renewable energy production possibilities, i.e. wind energy, solar energy, biofuels and biogas production, within these farms. Such farms can mitigate carbon emissions and offer resilience to probable climatic changes. Owing to the presence of diverse environments and various trophic levels, it can also support multiple species and hence have a role in biodiversity conservation. The study is a novel attempt to bring energy security to rural India while addressing climate change and biodiversity concerns. It should lead to ensuring sustainable livelihood options for small-holder farmers in India and potentially has global relevance. A number of policy options that may facilitate the transition are also briefly discussed.
LncRNA-ID: Long non-coding RNA IDentification using balanced random forests
Authors: Achawanantakun Rujira , Chen Jiao , Sun Yanni , Zhang Yuan
Published: August 2015

Motivation: Long non-coding RNAs (lncRNAs), which are non-coding RNAs of length above 200 nucleotides, play important biological functions such as gene expression regulation. To fully reveal the functions of lncRNAs, a fundamental step is to annotate them in various species. However, as lncRNAs tend to encode one or multiple open reading frames, it is not trivial to distinguish these long non-coding transcripts from protein-coding genes in transcriptomic data.

Results: In this work, we design a new tool that calculates the coding potential of a transcript using a machine learning model (random forest) based on multiple features including sequence characteristics of putative open reading frames, translation scores based on ribosomal coverage, and conservation against characterized protein families. The experimental results show that our tool competes favorably with existing coding potential computation tools in lncRNA identification.

Availability and implementation: The scripts and data can be downloaded at https://github.com/zhangy72/LncRNA-ID

Contact:  yannisun@msu.edu

Supplementary information:  Supplementary data are available at Bioinformatics online.