bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural and magnetic properties of Fe and carbon nanotubes derived from coconut shells
Authors: Qadri S. B. , Gorzkowski E. P. , Bussmann K. , Rath B. B. , Feng J.
Published: May 2018

Ferric oxide (Fe2O3) was directly reduced to metallic Fe using the carbon source from the coconut shells at temperatures above 1400 °C in argon gas atmospheres. X-ray diffraction analysis showed the presence of α-, γ- phases of Fe in addition to the presence of carbon nanotubes (CNTs). By selecting the appropriate ratios of coconut shell powder to Fe2O3, it is demonstrated that pure Fe is produced without any residual ferric oxide. The quantitative analysis of each of the Fe phases and carbon nanotubes was dependent on the temperature and the duration of processing at high temperature. Transmission electron microcopy results showed copious amount of carbon nanotubes in the samples. Magnetic property measurements suggested that, the average magnetic moment is consistent with presence of α-phase and the ferromagnetic γ-phase of Fe. This novel method of producing pure α- and γ-Fe in the presence of carbon nanotubes using coconut shells has potential applications as nanocomposites.
Simulation on the dynamic charge behavior of vacuum flashover developing across insulator involving outgassing
Authors: Sun Guang-Yu , Guo Bao-Hong , Song Bai-Peng , Su Guo-Qiang , Mu Hai-Bao , Zhang Guan-Jun
Published: May 2018

A 2D simulation based on particle-in-cell and Monte Carlo collision algorithm is implemented to investigate the accumulation and dissipation of surface charges on an insulator during flashover with outgassing in vacuum. A layer of positive charges is formed on the insulator after the secondary electrons emission (SEE) reaches saturation. With the build-up of local pressure resulting from gas desorption, the incident energy of electrons is affected by electron-neutral collisions and field distortion, remarkably decreasing the charge density on the insulator. Gas desorption ionization initiates near the anode, culminating, and then abates, followed by a steady and gradual augmentation as the negatively charged surface spreads towards the cathode and halts the SEE nearby. The initiation of flashover development is discussed in detail, and a subdivision of flashover development is proposed, including an anode-initiated desorption ionization avalanche, establishment of a plasma sheath, and plasma expansion. The transform from saturation to explosion of space charges and dissipation of the surface charge are revealed, which can be explained by the competition between multipactor electrons and ionized electrons.
Rate dependent behaviors of nickel-based microcapsules
Authors: Zhang Xin , Wang Pengfei , Sun Dawei , Li Xin , Yu T. X. , Yang En-Hua , Yang Jinglei
Published: May 2018

In this work, nickel-based microcapsules with liquid core were fabricated through an electroless plating approach. The quasi-static and high speed impact behaviors of microcapsules were examined by in-house assembled setups which are able to evaluate properties of materials and structures in microlevel accurately. Results indicated that the fabricated microcapsules showed strong rate sensitivity and the nominal strength of the capsule increased (up to 62.1%) with the increase in loading rates (up to 8200 s−1). The reduced modulus of nickel-based microcapsules was three orders of magnitude larger than that of the traditional microcapsules. The findings revealed that the fabricated nickel-based microcapsules produced remarkable performances for both static and dynamic loading applications. A high speed camera with stereo microscope was used to observe the failure mode of the microcapsule during the impact, which is of great importance to study the mechanical behaviours of materials and structures. Different failure modes were identified as multi-cracks with more rough and tortuous fracture surfaces and debris were observed for the samples subject to impact loading. Finite element method was employed to further understand the physical phenomenon which fitted well with the experimental results. These results could inspire more fundamental studies on the core-shell microstructures and potential applications in multifunctional materials.
Iso-thermal flow characteristics of rotationally symmetric jets generating a swirl within a cylindrical chamber
Authors: Long Shen , Lau Timothy C. W. , Chinnici Alfonso , Tian Zhao Feng , Dally Bassam B. , Nathan Graham J.
Published: May 2018

We present a systematic experimental study of the interaction between four rotationally symmetric jets within a cylindrical chamber, under conditions relevant to a wide range of engineering applications, including the technology of a Hybrid Solar Receiver Combustor (HSRC). The HSRC geometry is simplified here to a cylindrical cavity with four inlet jets (representing four burners) which are configured in an annular arrangement and aligned at an inclination angle to the axis with a tangential component (azimuthal angle) to generate a swirl in the chamber. In this study, the jet inclination angle (αj) was varied over the range of 25°–45°, while the jet azimuthal angle (θj) was varied from 5° to 15°. The inlet Reynolds number for each injected jet and the number of jets were fixed at ReD = 10 500 and 4, respectively. Measurements obtained with Particle Image Velocimetry were used to characterise the large-scale flow field within selected configurations. The results reveal a significant dependence of the mean and root-mean-square flow-fields on the jet azimuthal angle (θj) and the jet inclination angle (αj). Three different flow regimes with distinctive flow characteristics were identified within the configurations investigated here. It was also found that θj can significantly influence (a) the position and strength of an external recirculation zone and a central recirculation zone, (b) the extent of turbulence fluctuation, and (c) the flow unsteadiness. Importantly, the effect of αj on the flow characteristics was found to depend strongly on the value of θj.
Uncertainties in cylindrical anode current inferences on pulsed power drivers
Authors: Porwitzky Andrew , Brown Justin
Published: May 2018

For over a decade, velocimetry based techniques have been used to infer the electrical current delivered to dynamic materials properties experiments on pulsed power drivers such as the Z Machine. Though originally developed for planar load geometries, in recent years, inferring the current delivered to cylindrical coaxial loads has become a valuable diagnostic tool for numerous platforms. Presented is a summary of uncertainties that can propagate through the current inference technique when applied to expanding cylindrical anodes. An equation representing quantitative uncertainty is developed which shows the unfold method to be accurate to a few percent above 10 MA of load current.
3D-printed phase waveplates for THz beam shaping
Authors: Gospodaric J. , Kuzmenko A. , Pimenov Anna , Huber C. , Suess D. , Rotter S. , Pimenov A.
Published: May 2018

The advancement of 3D-printing opens up a new way of constructing affordable custom terahertz (THz) components due to suitable printing resolution and THz transparency of polymer materials. We present a way of calculating, designing, and fabricating a THz waveplate that phase-modulates an incident THz beam (λ0 = 2.14 mm) in order to create a predefined intensity profile of the optical wavefront on a distant image plane. Our calculations were performed for two distinct target intensities with the use of a modified Gerchberg-Saxton algorithm. The resulting phase-modulating profiles were used to model the polylactide elements, which were printed out with a commercially available 3D-printer. The results were tested in a THz experimental setup equipped with a scanning option, and they showed good agreement with theoretical predictions.
Effect of nanowire curviness on the percolation resistivity of transparent, conductive metal nanowire networks
Authors: Hicks Jeremy , Li Junying , Ying Chen , Ural Ant
Published: May 2018

We study the effect of nanowire curviness on the percolation resistivity of transparent, conductive metal nanowire networks by Monte Carlo simulations. We generate curvy nanowires as one-dimensional sticks using 3rd-order Bézier curves. The degree of curviness in the network is quantified by the concept of curviness angle and curl ratio. We systematically study the interaction between the effect of curviness and five other nanowire/device parameters on the network resistivity, namely nanowire density, nanowire length, device length, device width, and nanowire alignment. We find that the resistivity exhibits a power law dependence on the curl ratio, which is a signature of percolation transport. In each case, we extract the power-law scaling critical exponents and explain the results using geometrical and physical arguments. The value of the curl ratio critical exponent is not universal, but increases as the other nanowire/device parameters drive the network toward the percolation threshold. We find that, for randomly oriented networks, curviness is undesirable since it increases the resistivity. For well-aligned networks, on the other hand, some curviness is highly desirable, since the resistivity minimum occurs for partially curvy nanowires. We explain these results by considering the two competing effects of curviness on the percolation resistivity. The results presented in this work can be extended to any network, film, or nanocomposite consisting of one-dimensional nanoelements. Our results show that Monte Carlo simulations are an essential predictive tool for both studying the percolation transport and optimizing the electronic properties of transparent, conductive nanowire networks for a wide range of applications.
Ultrafast dynamic response of single-crystal β-HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine)
Authors: Zaug Joseph M. , Austin Ryan A. , Armstrong Michael R. , Crowhurst Jonathan C. , Goldman Nir , Ferranti Louis , Saw Cheng K. , Swan Raymond A. , Gross Richard , Fried Laurence E.
Published: May 2018

We report experimental and computational studies of shock wave dynamics in single-crystal β-HMX on an ultrafast time scale. Here, a laser-based compression drive (∼1 ns in duration; stresses of up to ∼40 GPa) is used to propagate shock waves normal to the (110) and (010) lattice planes. Ultrafast time-domain interferometry measurements reveal distinct, time-dependent relationships between the shock wave velocity and particle velocity for each crystal orientation, which suggest evolving physical processes on a sub-nanosecond time scale. To help interpret the experimental data, elastic shock wave response was simulated using a finite-strain model of crystal thermoelasticity. At early propagation times (<500 ps), the model is in agreement with the data, which indicates that the mechanical response is dominated by thermoelastic deformation. The model agreement depends on the inclusion of nonlinear elastic effects in both the spherical and deviatoric stress-strain responses. This is achieved by employing an equation-of-state and a pressure-dependent stiffness tensor, which was computed via atomistic simulation. At later times (>500 ps), the crystal samples exhibit signatures of inelastic deformation, structural phase transformation, or chemical reaction, depending on the direction of wave propagation.
Numerical study of bandwidth effect on stimulated Raman backscattering in nonlinear regime
Authors: Zhou H. Y. , Xiao C. Z. , Zou D. B. , Li X. Z. , Yin Y. , Shao F. Q. , Zhuo H. B.
Published: May 2018

Nonlinear behaviors of stimulated Raman scattering driven by finite bandwidth pumps are studied by one dimensional particle-in-cell simulations. The broad spectral feature of plasma waves and backscattered light reveals the different coupling and growth mechanisms, which lead to the suppression effect before the deep nonlinear stage. It causes nonperiodic plasma wave packets and reduces packet and etching velocities. Based on the negative frequency shift and electron energy distribution, the long-time evolution of instability can be divided into two stages by the relaxation time. It is a critical time after which the alleviation effects of nonlinear frequency shift and hot electrons are replaced by enhancement. Thus, the broadband pump suppresses instability at early time. However, it aggravates in the deep nonlinear stage by lifting the saturation level due to the coupling of the incident pump with each frequency shifted plasma wave. Our simulation results show that the nonlinear effects are valid in a bandwidth range from 2.25% to 3.0%, and the physics are similar within a nearby parameter space.
Fluctuation effects in blends of A + B homopolymers with AB diblock copolymer
Authors: Spencer Russell K. W. , Matsen Mark W.
Published: May 2018

Field-theoretic simulations (FTSs) are performed on ternary blends of A- and B-type homopolymers of polymerization Nh and symmetric AB diblock copolymers of polymerization Nc. Unlike previous studies, our FTSs are conducted in three-dimensional space, with the help of two new semi-grand canonical ensembles. Motivated by the first experiment to discover bicontinuous microemulsion (BμE) in the polyethylene-polyethylene propylene system, we consider molecules of high molecular weight with size ratios of α ≡ Nh/Nc = 0.1, 0.2, and 0.4. Our focus is on the A + B coexistence between the two homopolymer-rich phases in the low-copolymer region of the phase diagram. The Scott line, at which the A + B phases mix to form a disordered melt with increasing temperature (or decreasing χ), is accurately determined using finite-size scaling techniques. We also examine how the copolymer affects the interface between the A + B phases, reducing the interfacial tension toward zero. Although comparisons with self-consistent field theory (SCFT) illustrate that fluctuation effects are relatively small, fluctuations do nevertheless produce the observed BμE that is absent in the SCFT phase diagram. Furthermore, we find evidence of three-phase A + B + BμE coexistence, which may have been missed in the original as well as subsequent experiments.
PO calculation for reduction in radar cross section of hypersonic targets using RAM
Authors: Liu Song-hua , Guo Li-xin , Pan Wei-tao , Chen Wei , Xiao Yi-fan
Published: May 2018

The radar cross section (RCS) reduction of hypersonic targets by radar absorbing materials (RAM) coating under different reentry cases is analyzed in the C and X bands frequency range normally used for radar detection. The physical optics method is extended to both the inhomogeneous plasma sheath and RAM layer present simultaneously. The simulation results show that the absorbing coating can reduce the RCS of the plasma cloaking system and its effectiveness is related to the maximum plasma frequency. Moreover, the amount of the RCS decrease, its maxima, and the corresponding optimal RAM thickness depend on the non-uniformity and parameters of the plasma sheath. In addition, the backward RCS of the flight vehicle shrouded by plasma shielding and man-made absorber is calculated and compared to the bare cone.
Enhanced energy absorption of high intensity laser pulses by targets of modulated surface
Authors: Cerchez M. , Swantusch M. , Toncian M. , Zhu X. M. , Prasad R. , Toncian T. , Rödel Ch. , Jäckel O. , Paulus G. G. , Andreev A. A. , Willi O.
Published: May 2018

Investigations of energy transfer of high intensity (I = 5 × 1019 W/cm2), ultrashort (<30 fs) Ti:Sa laser pulses to solid targets with a randomly rough surface have been performed. We investigated the influence of the target surface morphology on the efficiency of energy transfer of p- polarized laser pulses characterized by a very high contrast. Targets with a roughness σ larger than ∼20% of the laser wavelength proved to absorb a remarkably large fraction of energy reaching up to 70%, almost independent of the incidence angle. Numerical simulations of various interaction conditions are in agreement with the experimental data and confirm the effect of the target morphology and its surface parameters on the enhanced energy absorbed fraction.
Research Update: Ab initio study on resistive memory device optimization trends: Dopant segregation effects and data retention in HfO2−x
Authors: Magyari-Köpe Blanka , Song Yali , Duncan Dan , Zhao Liang , Nishi Yoshio
Published: May 2018

Segregation energy trends and their charge state dependence were established for Group II to Group VI substitutional metal dopants in HfO2 using density functional theory. Corroborating the segregation energy with dopant-oxygen bond lengths and charge state stability, strong effects are predicted for Group II and Group III p-type dopants, which can easily reverse their segregation trend due to −2 charge state preference. Transitions between segregation and isolation may occur around 1.5 eV above the valence band maximum, with the exception of Al, which remains barely stable in its segregated form. In Al-doped HfOx, the switching characteristics of filaments formed near Al dopants show subtle changes and the OFF state data retention is degraded. A comprehensive assessment on configurational Al-VO interaction, charge state dependence, and migration energy changes points to the fact that to achieve OFF state data retention improvements, it will be necessary to engineer the filament interaction with Al to stabilize configurations that favor vacancy filament dissolution. Another mode of failure can result from subsequent charge trapping during the operation of the device, which ultimately prohibits the filament dissociation.
Design of dispersion-engineered As2Se3 channel waveguide for mid-infrared region supercontinuum generation
Authors: Karim M. R. , Ahmad H. , Ghosh S. , Rahman B. M. A.
Published: May 2018

In recent years, low cost and scalable integrated optics compatible planar waveguides have emerged for an ultrabroadband supercontinuum generation between ultraviolet and mid-infrared region applications. A 20-mm-long integrated photonics compatible highly nonlinear As2Se3 channel waveguide, which exhibited wider as well as lower magnitude and nearly flat anomalous dispersion region, designed and modeled by employing GeAsSe glass for its upper and lower claddings. Using pump source at 6 μm with a pulse duration of 170-fs, an ultrabroadband long wavelength region supercontinuum broadening covering the wavelength from 3.5 μm to 15 μm could be predicted with the largest input peak power of 10 kW. Increasing the power further to 20 kW does not enhance the supercontinuum expansion noticeably beyond 15 μm. This numerical demonstration could be the longest supercontinuum generation by an on-chip integrated photonics compatible planar waveguide which can be used for a variety of mid-infrared region applications.
Efficient injection of radiation-pressure-accelerated sub-relativistic protons into laser wakefield acceleration based on 10 PW lasers
Authors: Liu M. , Weng S. M. , Wang H. C. , Chen M. , Zhao Q. , Sheng Z. M. , He M. Q. , Li Y. T. , Zhang J.
Published: May 2018

We propose a hybrid laser-driven ion acceleration scheme using a combination target of a solid foil and a density-tailored background plasma. In the first stage, a sub-relativistic proton beam can be generated by radiation pressure acceleration in intense laser interaction with the solid foil. In the second stage, this sub-relativistic proton beam is further accelerated by the laser wakefield driven by the same laser pulse in a near-critical-density background plasma with decreasing density profile. The propagating velocity of the laser front and the phase velocity of the excited wakefield wave are effectively lowered at the beginning of the second stage. By decreasing the background plasma density gradually from near critical density along the laser propagation direction, the wake travels faster and faster, while it accelerates the protons. Consequently, the dephasing between the protons and the wake is postponed and an efficient wakefield proton acceleration is achieved. This hybrid laser-driven proton acceleration scheme can be realized by using ultrashort laser pulses at the peak power of 10 PW for the generation of multi-GeV proton beams.
Barium ions in liquid helium
Authors: Chikina I. , Shikin V.
Published: May 2018

We discuss the properties of barium clusters (neutral or charged) implanted into liquid helium and propose a model where individual barium atoms cannot form negative ions, whereas a barium cluster composed of many barium atoms can. This property is important from the standpoint of applications involving laser ablation of barium metal surfaces in liquid helium. We note the qualitative differences in the mechanisms of formation of quasi-one-dimensional chains of metal or dielectric dust during its implantation into superfluid helium. A likely scenario for a dispersed metal is the dendritic breakdown in a parallel plate capacitor filled with metal dust and a finite potential difference between the plates. It is not possible to use the dendritic mechanism of cluster evolution for the dielectric problem and the details of this mechanism do not agree well with existing observations. We outline a scenario alternative to the vortex formation of long chains with dielectric links.
Electrical and thermal conductivity of the Ti3AlC2 MAX phase at low temperatures
Authors: Khadzhai G. Ya. , Vovk R. V. , Prichna T. A. , Gevorkyan E. S. , Kislitsa M. V. , Solovjov A. L.
Published: May 2018

Electrical and thermal conductivities of a sample containing 96% of MAX-phase Ti3AlC2 and 4% of TiC were experimentally studied in the temperature range of 15–300 K. The maximum thermal conductivity is observed at approximately 75 K. As the temperature increases, the fraction of phonon heat transfer decreases from ∼90% at low temperatures to ∼40% at the room temperature.
Multi-scale electron microscopy of overnitrided Sm-Fe-Mn-N powder
Authors: Hosokawa Akihide , Takagi Kenta
Published: May 2018

Multi-scale electron microscopy technique that combines transmission electron microscopy (TEM) and focused ion beam - scanning electron microscopy (FIB-SEM) was utilized to investigate the influences of the change in microstructure of Sm2(Fe0.95Mn0.05)17Nx by overnitridation on the magnetic properties. The recent high-contrast backscatter electron imaging technique in SEM machines enabled us to reveal the formation events of cell-like microstructure from a quite large field of view. In addition, detailed TEM observations revealed the crystallographic orientations of the cells as well as the local chemical fluctuation. The combination of these techniques allows us to understand the microstructural hierarchy in this material, verifying that the original orientations of the individual particles are inherited to the nanocrystalline cells formed by overnitridation.
Antiferroelectricity in lanthanum doped zirconia without metallic capping layers and post-deposition/-metallization anneals
Authors: Wang Zheng , Gaskell Anthony Arthur , Dopita Milan , Kriegner Dominik , Tasneem Nujhat , Mack Jerry , Mukherjee Niloy , Karim Zia , Khan Asif Islam
Published: May 2018

We report the effects of lanthanum doping/alloying on antiferroelectric (AFE) properties of ZrO2. Starting with pure ZrO2, an increase in La doping leads to the narrowing of the AFE double hysteresis loops and an increase in the critical voltage/electric field for AFE → ferroelectric transition. At higher La contents, the polarization-voltage characteristics of doped/alloyed ZrO2 resemble that of a non-linear dielectric without any discernible AFE-type hysteresis. X-ray diffraction based analysis indicates that the increased La content while preserving the non-polar, parent AFE, tetragonal P42/nmc phase leads to a decrease in tetragonality and the (nano-)crystallite size and an increase in the unit cell volume. Furthermore, antiferroelectric behavior is obtained in the as-deposited thin films without requiring any capping metallic layers and post-deposition/-metallization anneals due to which our specific atomic layer deposition system configuration crystallizes and stabilizes the AFE tetragonal phase during growth.
Magnetic and transport properties driven by Sr substitution in polycrystalline Pr1-xSrxCoO3 (0.1 ≤ x ≤ 0.5) cobaltites
Authors: Modi Anchit , Ahmad Bhat Masroor , Bhattacharya Shovit , Okram G. S. , Gaur N. K.
Published: May 2018

The effect of strontium (Sr) doping on the structural, magnetic, electrical, and thermal properties of Pr1-xSrxCoO3 (0.1 ≤ x ≤ 0.5) has been studied. The samples were synthesized by using the conventional solid-state reaction method. The Rietveld refinement of X-ray diffraction patterns confirms the single-phase composition with orthorhombic (Pbnm) perovskite symmetry. The magnetization measurements revealed the paramagnetic to ferromagnetic transition and the transition temperature (Tc) increased with increasing Sr doping. The effective magnetic moments determined by the Curie-Weiss law show an increase in the Sr concentration. The temperature dependence of electrical resistivity suppressed with increasing the Sr content. Moreover, all the compounds other than x = 0.5 show the semiconducting nature. All semiconductor compositions (x = 0.1, 0.2, 0.3, and 0.4) in the high temperature region can be explained within the framework of the small polaron hopping model and the variable range hopping model, whereas the metallic composition (x = 0.5) is explained by electron-electron, electron-phonon, and electron-spin fluctuation scattering processes. The Seebeck coefficient (S) for all the samples except x= 0.5 is found to be positive, thereby confirming the applicability of the small polaron hopping model in the high-temperature region. The sample with x = 0.5 exhibits a crossover in S from positive to negative values and again attains a positive value.
Ions drive macroscopic flows in water
Authors: Cesare Chris
Published: May 2018

A low-voltage technique for generating fluid flows may provide new approach for transport in biological lab-on-a-chip devices.
Synthesis of oxygen-containing heterocyclic compounds based on monoterpenoids
Authors: Patrusheva Oksana S. , Volcho Konstantin P. , Salakhutdinov Nariman F.
Published: May 2018

The review integrates data on the synthesis of chiral oxygen-containing heterocycles of various structural types by reactions of monoterpenoids with carbonyl compounds. Depending on the structure of the monoterpene and carbonyl components and the catalyst used, these reactions lead to mono-, bi-, tri- or tetracyclic products. The possible reaction mechanisms are discussed and data on the biological activities of the products are given.

The bibliography includes 125 references.
Nanosized vehicles for delivery of photosensitizers in photodynamic diagnosis and therapy of cancer
Authors: Mironov Andrey F. , Zhdanova Kseniya A. , Bragina Natal’ya A.
Published: May 2018

The review summarizes the state of the art of research in the field of nanosized vehicles for delivery of photosensitizers for diagnosis and treatment of malignant neoplasms by photodynamic cancer therapy. Data on the utilization of porphyrin- and phthalocyanine-based photosensitizers in medical practice, the employment of vehicles for their delivery and the development of new effective medications are considered. The review focuses on the most commonly used and proven vehicles based on lipids, lipoproteins and polymers. Strategies for increasing efficiency of nanosized delivery vehicles using various vector molecules specific to different types of cancer are discussed. A systematic analysis of the published data is presented and the available tools for increasing the efficacy of photodynamic therapy by means of nanosized delivery vehicles are assessed.

The bibliography includes 188 references.
Catalytic asymmetric oxidations using molecular oxygen
Authors: Ottenbacher Roman V. , Talsi Evgenii P. , Bryliakov Konstantin P.
Published: May 2018

Catalytic enantioselective oxygen transfer reactions have been a long-standing goal of synthetic chemistry. The use of molecular oxygen in these oxidations has engaged significant research efforts for decades. The present review considers the state of the art of aerobic asymmetric oxidations mediated by chiral organocatalysts and transition metal catalysts, occurring with formation of new C–O bonds, i.e. oxygenations. The milestones and limitations of existing approaches are discussed, with focus on catalyst design and catalytic performance.

The bibliography includes 41 references.
Number of tillers in wheat is an easily measurable index of genotype tolerance to saline waterlogged soils: evidence from 10 large-scale field trials in India
Authors: Singh Gyanendra , Setter Timothy L. , Singh Muneendra Kumar , Kulshreshtha Neeraj , Singh Bhupendra Narayan , Stefanova Katia , Tyagi Bhudeva Singh , Singh Jang Bahadur , Kherawat Bhagwati S. , Barrett-Lennard Edward G.
Published: May 2018

Over 100 wheat varieties and breeding lines from India and Australia were screened in alkaline and waterlogged soils in 10 environments over two years at one drained location and two naturally waterlogged locations in India. Mean trial grain yield was reduced up to 70% in the environments where genotypes were waterlogged for up to 15 days at the vegetative stage in alkaline soil relative to plants in drained soils. Agronomic traits (plant height, tiller number, 1000-grain weight) of genotypes were also reduced under waterlogging. At one waterlogged site, up to 68% of the genetic diversity for predicted grain yields under waterlogging could be accounted for by number of tillers (r2 = 0.41–0.68 in 2011 and 2010, respectively) and positive correlations also occurred at the second site (r2 = 0.19–0.35). However, there was no correlation between grain yields across varieties under waterlogging in any trials at the two waterlogged locations. This may have occurred because waterlogged sites differed up to 4-fold in soil salinity. When salinity was accounted for, there was a good correlation across all environments (r2 = 0.73). A physiological basis for the relationship between tillering and waterlogging tolerance is proposed, associated with crown root development. Results are compared with findings in Australia in acidic soils, and they highlight major opportunities for wheat improvement by selection for numbers of tillers when crops are waterlogged during vegetative growth.
Commentary pragmatic markers in Nigerian English
Authors: Unuabonah Foluke Olayinka , Gut Ulrike
Published: May 2018

This article investigates the use of commentary pragmatic markers in Nigerian English. The frequency and stylistic variability of five types of commentary markers – assessment, manner of speaking, evidential, hearsay and emphasis markers – were examined in ICE-Nigeria and compared with ICE-Great Britain. The results reveal that Nigerian English has patterns of use of pragmatic markers that differ systematically from British English: speakers of Nigerian English use an overall lower frequency and a reduced inventory of commentary pragmatic markers compared to British English, show distinct preference patterns for individual pragmatic markers and demonstrate different stylistic variability in the use of pragmatic markers. Some of the preference patterns may be influenced by Nigerian languages and socio-cultural norms.
Register variation in spoken British English
Authors: Laws Jacqueline , Ryder Chris
Published: May 2018

The aim of this paper is to identify the effect of register variation in spoken British English on the occurrence of the four principal verb-forming suffixes: ‑ate, ‑en, ‑ifyand ‑ize, by building on the work ofBiber et al. (1999),Plag et al. (1999)andSchmid (2011). Register variation effects were compared between the less formal Demographically-Sampled and the more formal Context-Governed components of the original 1994 version of the British National Corpus. The pattern of ‑izederivatives revealed the most marked register-based differences with respect to frequency counts and the creation of neologisms, whereas ‑enderivatives varied the least compared with the other three suffixes. Quantitative and qualitative analyses of these suffix profiles in the context of spoken language reveal markers of register formality that have not hitherto been explored; derivative usage patterns provide an additional dimension to previous research on register variation which has mainly focused on grammatical and lexical features of language.
Shell noun use in English argumentative essays by native speakers of Japanese, Turkish, and English
Authors: Schanding Brian , Pae Hye K.
Published: May 2018

Shell noun (SN) use in learner writing has been studied in terms of SN choices and SN pattern choices, but less so in terms of SN-pattern co-selection (i.e. which patterns are used with which SNs). This study examined English SN choices and their preferred lexicogrammatical patterns in argumentative essays by speakers of Turkish and Japanese in order to find SN-pattern attraction in learner writing, compared to SN use in writing of native English speakers. Results indicate that learners understand SN functions, given pattern frequencies comparable to those of native speakers. However, there were differences among groups in which SNs were most strongly attracted to or repelled by the SN patterns. This prompted a qualitative investigation. Findings of non-native SN use are discussed with respect to word-sense categories and clause marking. Suggestions are made for further research.
Precision and imprecision in second language pronunciation
Authors: Levis John M.
Published: May 2018

Any discipline requires precision in critical issues while tolerating and perhaps even welcoming imprecision in other respects. This editorial discusses areas in second language pronunciation research in which precision is required (the use of terminology such as intelligibility and comprehensibility), where it is not always required to the same extent (the use of phonetic and phonemic symbols), and where it is rarely required (in how L2 learners are given explanations or ways to pronounce more accurately). The article then describes the content of the full-length articles, commentary and reviews.
Engaging the senses
Authors: Cerreta Suzanne , Trofimovich Pavel
Published: May 2018

This case study examined the benefits of a sensory-based approach for teaching second language pronunciation to actors, addressing the unique learning goal of nativelike speech for nonnative professional actors. Two French Canadian actors (Marianne and Sebastian) were followed over 10 weeks of pronunciation instruction based on Knight’s (2012) theatrical voice methods and Gibson’s (1969) principles of sensory learning. Audio samples from scripted performances before and after instruction were rated for global and linguistic measures by 10 linguistically trained listeners and for performance measures by 10 advanced acting students. Listener ratings showed a significant improvement in accentedness for Marianne and greater comprehensibility for both actors, while qualitative data revealed actors’ preferences for different types of instruction. Results suggest that sensory learning appears beneficial for some learners and that pronunciation instruction could be supplemented with sensory-based activities.
Variation in hesitation
Authors: Graham Lamar A.
Published: May 2018

This study explored the influence of social and syntactic-pragmatic factors on a speaker’s choice between hesitation markers
este and eh in oral discourse. Data collected from San Juan (PR), Mexico City, Montevideo,
and Medellín were analyzed as a large corpus and on an individual country basis. Este was found to be the most
prevalent hesitation marker overall and within three of the four countries studied. On an overall level, the factors of city,
education level, gender, and position of the marker within the turn were found to be statistically significant to hesitation
marker choice, while age was not. On a per-city basis, education was significant everywhere, age and gender were significant
everywhere except Medellín, and turn position was significant everywhere except San Juan. The lack of uniformity in the results
suggests that speakers’ choice between este and eh is affected differently by these factors in
each area.
Análisis cognitivo-discursivo y situacional de las formas de tratamiento en función de sujeto y de objeto en español
Authors: Serrano María José
Published: May 2018

Abstracto

Las formas de sujeto y de objeto de segunda persona singulartú/ustedyte/a ti; le, lo, la/a ustedson recursos que posee la lengua española para indexar a los participantes en las distintas situaciones discursivas. Pocos estudios han profundizado en los valores cognitivos que subyacen a esta elección y, de forma general, se prefiere seguir aludiendo al eje de solidaridad-poder para su explicación. Para ello se suele recurrir a un conjunto de factores meramente descriptivos (edad, distancia social, respeto, etc.). Este trabajo pretende contribuir al desarrollo del conocimiento de estos pronombres desde una perspectiva discursivo-cognitiva y situacional, que, además presenta como novedad la distinción entre las funciones de sujeto pronominal y objeto de persona. Para ello se realizará un análisis cognitivo-discursivo basado en la prominencia de los referentes de estas formas en distintos géneros y situaciones comunicativas y entre hablantes de distintas afiliaciones socioprofesionales. Se utilizarán textos delCorpus Conversacional del Español de Canarias(CCEC).
Green tea extracts reduce leukocyte cell–Derived chemotaxin 2 and selenoprotein P levels in the livers of C57BL/6J mice fed a high-fat diet
Authors: Onishi Shintaro , Kitazawa Hidefumi , Meguro Shinichi , Tokimitsu Ichiro
Published: May 2018

Epidemiological studies suggest that green tea extracts (GTEs), including catechins such as epigallocatechin gallate and epicatechin gallate, have a beneficial effect on obesity, hyperglycemia, insulin resistance, endothelial dysfunction, and inflammation. Although several studies have shown that catechins directly modulate the cellular and molecular alterations in the liver tissue, the contributions of indirect mechanisms underlying these systemic effects of catechins remain unclear. In this study, we report that, in the C57BL/6J mouse liver, GTEs reduce high-fat diet-induced increases in the levels of hepatokines, liver-derived secretary proteins such as leukocyte cell-derived chemotaxin 2 and selenoprotein P production, which have been shown to induce systemic adverse effects, including several metabolic diseases. These findings suggest that the systemic effects of GTEs involve the regulation of hepatokine production as an indirect mechanism.
Using laser profilometry to monitor electrode wear during resistance spot welding
Authors: Bražun D. , Diaci J. , Polajnar I. , Možina J.
Published: May 2018

A new method for rapid and accurate acquisition of the shape of an electrode indentation in a workpiece during resistance spot welding (RSW) is presented. The method is based on illumination of the indentation with structured laser light and detection of the image of the illuminated object using a charge coupled device camera. The image from the camera is digitised using a frame grabber and fed into a personal computer where it is processed and analysed. This paper presents the basic principles of the method and discusses the image processing algorithms developed to measure the indentation shape characteristics, such as diameter, depth, and volume. Results from an application of the method to study electrode wear during RSW of zinc coated steel are also presented.
Plasma arc brazing in sheet metal construction
Authors: Bouaifi B. , Ouaissa B. , Helmich A.
Published: May 2018

Because of the high heat input required, conventional welding methods may not always be ideal for mild and high strength steel sheets. A possible alternative in some applications is plasma brazing, which can also serve as a supplement to other joining techniques. A characteristic feature of the process is the separation between the energy input and filler material. Compared with high heat processes, plasma brazing causes considerably less distortion of joints or panels. Almost no spatter results from the process. The brazed seams exhibit sound mechanical properties as well as good appearance. However, there are difficulties associated with brazing some high strength steels using the filler wires commercially available at present.
1399 H&E-stained sentinel lymph node sections of breast cancer patients: the CAMELYON dataset
Authors: Litjens Geert , Bandi Peter , Ehteshami Bejnordi Babak , Geessink Oscar , Balkenhol Maschenka , Bult Peter , Halilovic Altuna , Hermsen Meyke , van de Loo Rob , Vogels Rob , Manson Quirine F , Stathonikos Nikolas , Baidoshvili Alexi , van Diest Paul , Wauters Carla , van Dijk Marcory , van der Laak Jeroen
Published: May 2018

Background

The presence of lymph node metastases is one of the most important factors in breast cancer prognosis. The most common way to assess regional lymph node status is the sentinel lymph node procedure. The sentinel lymph node is the most likely lymph node to contain metastasized cancer cells and is excised, histopathologically processed, and examined by a pathologist. This tedious examination process is time-consuming and can lead to small metastases being missed. However, recent advances in whole-slide imaging and machine learning have opened an avenue for analysis of digitized lymph node sections with computer algorithms. For example, convolutional neural networks, a type of machine-learning algorithm, can be used to automatically detect cancer metastases in lymph nodes with high accuracy. To train machine-learning models, large, well-curated datasets are needed.

Results

We released a dataset of 1,399 annotated whole-slide images (WSIs) of lymph nodes, both with and without metastases, in 3 terabytes of data in the context of the CAMELYON16 and CAMELYON17 Grand Challenges. Slides were collected from five medical centers to cover a broad range of image appearance and staining variations. Each WSI has a slide-level label indicating whether it contains no metastases, macro-metastases, micro-metastases, or isolated tumor cells. Furthermore, for 209 WSIs, detailed hand-drawn contours for all metastases are provided. Last, open-source software tools to visualize and interact with the data have been made available.

Conclusions

A unique dataset of annotated, whole-slide digital histopathology images has been provided with high potential for re-use.
Motivational Theories of Agenda-Setting Effects: An Information Selection and Processing Model of Attribute Agenda-Setting
Authors: Camaj Lindita
Published: May 2018

This study explores how agenda-setting theory works in a fragmented media environment while examining psychological motivations that drive selective exposure and information processing in an electoral context. The data suggest that regardless of motivational goals, people with a moderate active need for orientation (NFO) spent more time engaged in cross-network exposure to news media than the other groups. However, driven by directional goals, they were more apt to engage in biased information processing that increased agenda-setting outcomes on candidate attributes. Overall, this study suggests that NFO predicts information-seeking behavior, while motivated reasoning explains how people processed information. Exposure to partisan news reporting on cable television exhibited the strongest agenda-setting associations on candidate attributes.
Parenting Attitudes and Public Support for Political Authoritarianism in Latin America
Authors: Azpuru Dinorah , Malone Mary Fran T
Published: May 2018

Despite nearly three decades of democratic rule throughout the Latin American region, public support for authoritarian norms has persisted. These “pockets of authoritarianism” can bolster support for policies and practices that weaken democratic governance, such as allowing authorities to abuse power. We examine why some Latin Americans endorse nondemocratic governance options by testing the predictive power of a psychological measure of authoritarianism, operationalized as support for particular child-rearing practices. We find that this psychological variable explains support for several nondemocratic governance options in the region: presidential limits on the opposition, iron-fist policies, torture of suspected criminals, and a military coup. Authoritarian parenting attitudes are also correlated with perceptions that political minorities threaten the country and lower support for democracy.
Anti-leukemic effects of all-trans retinoic acid in combination with Daratumumab in acute myeloid leukemia
Authors: Buteyn Nathaniel J , Fatehchand Kavin , Santhanam Ramasamy , Fang Huiqing , Dettorre Gino M , Gautam Shalini , Harrington Bonnie K , Henderson Sally E , Merchand-Reyes Giovanna , Mo Xiaokui , Benson Don M , Carson William E , Vasu Sumithira , Byrd John C , Butchar Jonathan P , Tridandapani Susheela
Published: May 2018

Acute myeloid leukemia (AML) remains a significant health problem, with poor outcomes despite chemotherapy and bone marrow transplants. Although one form of AML, acute promyelocytic leukemia (APL), is successfully treated with all-trans retinoic acid (ATRA), this drug is seemingly ineffective against all other forms of AML. Here, we show that ATRA up-regulates CD38 expression on AML blasts to sufficient levels that promote antibody-mediated fratricide following the addition of anti-CD38 daratumumab (DARA). The combination of ATRA plus DARA induced Fc-dependent conjugate formation and cytotoxicity among AML blasts in vitro. Combination treatment also led to reduction in tumor volume and resulted in increased overall survival in murine engraftment models of AML. These results suggest that, although ATRA does not induce differentiation of non-APL, it may be effective as a therapy in conjunction with DARA.
How to Solve the Puzzle of Dion and Theon Without Losing Your Head
Authors: Carmichael Chad
Published: May 2018

The ancient puzzle of Dion and Theon has given rise to a surprising array of apparently implausible views. For example, in order to solve the puzzle, several philosophers have been led to deny the existence of their own feet, others have denied that objects can gain and lose parts, and large numbers of philosophers have embraced the thesis that distinct objects can occupy the same space, having all their material parts in common. In this paper, I argue for an alternative approach: I claim that human beings have ordinary parts—hands, heads, feet, and so on—but no extraordinary parts, such as ‘foot-complements’, the existence of which is essential to the puzzle. I rebut three objections to this approach: an objection that it is unacceptably metaphysically arbitrary, an objection that the view is incompatible with versions of the puzzle involving decapitation, and an objection concerning masses of matter. If we can believe that there are such things as hands and feet without involving ourselves in paradox, and without accepting large numbers of co-located material objects that share all their material parts, then that is what we should do. My view is the only known alternative which allows this.
Constraining the geometry of AGN outflows with reflection spectroscopy
Authors: Parker M L , Buisson D J K , Jiang(姜嘉陈) J , Gallo L C , Kara E , Matzeu G A , Walton D J
Published: May 2018

We collate active galactic nuclei (AGN) with reported detections of both relativistic reflection and ultrafast outflows. By comparing the inclination of the inner disc from reflection with the line-of-sight velocity of the outflow, we show that it is possible to meaningfully constrain the geometry of the absorbing material. We find a clear relation between the velocity and inclination, and demonstrate that it can potentially be explained either by simple wind geometries or by absorption from the disc surface. Due to systematic errors and a shortage of high-quality simultaneous measurements our conclusions are tentative, but this study represents a proof-of-concept that has a great potential.