bluuebunny/crossref_metadata_2025 huggingface dataset:
Local measurements of the spatial magnetic field distribution in a z-pinch plasma during and near stagnation using polarization spectroscopy
Authors: Rosenzweig G. , Kroupp E. , Queller T. , Starobinets A. , Maron Y. , Tangri V. , Giuliani J. L. , Fruchtman A.
Published: February 2020

We present here the detailed measurements of radial distribution of the magnetic field in a gas-puff z-pinch plasma at the final stages of the implosion phase and at stagnation. While the measurements are chordal, the radial distribution of different charge states was utilized to measure the magnetic field locally for certain radii, so that unlike chordal measurements in general, the magnetic field radial distribution was obtained with no need for the Abel inversion of the data. The distribution was measured using the Zeeman effect via a novel spectroscopic technique, at several axial locations, and demonstrates striking features such as the peak field remaining at a radius much larger than the stagnation radius at all times. Furthermore, while the distribution observed is sometimes monotonic with respect to the radius, it is often not, a behavior that can be linked to 2D features in the plasma column resulting from the Rayleigh–Taylor instability. The current flowing through the stagnating plasma was found to be a small fraction of the total current, resulting in clearly insufficient magnetic pressure to balance the plasma pressure at stagnation. The magnetic field data, taken over several axial positions, are used to obtain the true inductance in the imploding plasma for the first time; it is found that the data cannot explain the current turnover at stagnation. A simulation with the MACH2-Tabular Collisional-Radiative Equilibrium magnetohydrodynamics code in the r–z plane shows that the peak of the magnetic field pinches to a much smaller radius than is observed in the spectroscopic data. Furthermore, the depth of the computed current turnover at stagnation is smaller than the measured one. The two observed features of a radially extended magnetic field at stagnation together with a deep current turnover are a challenge to match in simulations. Various calculations and estimates of the inductive and resistive load voltages are examined to ascertain if they are responsible for the observed current notch. The results demonstrate that the knowledge of the true inductance in the driven load requires such magnetic-field-distribution measurements and that imaging data or electrical measurements are insufficient.
Studying rare events using forward-flux sampling: Recent breakthroughs and future outlook
Authors: Hussain Sarwar , Haji-Akbari Amir
Published: February 2020

Rare events are processes that occur upon the emergence of unlikely fluctuations. Unlike what their name suggests, rare events are fairly ubiquitous in nature, as the occurrence of many structural transformations in biology and material sciences is predicated upon crossing large free energy barriers. Probing the kinetics and uncovering the molecular mechanisms of possible barrier crossings in a system is critical to predicting and controlling its structural and functional properties. Due to their activated nature, however, rare events are exceptionally difficult to study using conventional experimental and computational techniques. In recent decades, a wide variety of specialized computational techniques—known as advanced sampling techniques—have been developed to systematically capture improbable fluctuations relevant to rare events. In this perspective, we focus on a technique called forward flux sampling [Allen et al., J. Chem. Phys. 124, 024102 (2006)] and overview its recent methodological variants and extensions. We also provide a detailed overview of its application to study a wide variety of rare events and map out potential avenues for further explorations.
Electronegative ligands enhance charge transfer to Mn12 single-molecule magnets deposited on graphene
Authors: Zhu Xiaochen , Hale Ashlyn , Christou George , Hebard Arthur F.
Published: February 2020

Combining single-molecule magnets (SMMs) and emergent two-dimensional substrates such as graphene may lead to device configurations that are promising for spintronics and quantum computing. However, to fully exploit the unique features of SMMs anchored to two-dimensional substrates, the choice of ligand attachments, which could affect the magnetic and electronic properties, is critical. In this work, we focus on hybrid junctions comprising CVD-grown graphene and [Mn12O12(O2CR)16(H2O)4](R=CH3,CHCl2) SMMs with different ligands. We find that [Mn12O12(O2CCH3)16(H2O)4] SMMs barely change the graphene’s conductivity, while [Mn12O12(O2CCHCl2)16(H2O)4] SMMs with more electronegative ligands, by means of charge transfer, remarkably modify the electronic transport in graphene as revealed by gate-voltage dependent magnetotransport measurements.
Vacuum-compatible photon-counting hybrid pixel detector for wide-angle x-ray scattering, x-ray diffraction, and x-ray reflectometry in the tender x-ray range
Authors: Skroblin D. , Schavkan A. , Pflüger M. , Pilet N. , Lüthi B. , Krumrey M.
Published: February 2020

A vacuum-compatible photon-counting hybrid pixel detector has been installed in the ultra-high vacuum reflectometer of the four-crystal monochromator beamline of the Physikalisch-Technische Bundesanstalt at the electron storage ring BESSY II in Berlin, Germany. The setup is based on the PILATUS3 100K module. The detector can be used in the entire photon energy range accessible at the beamline from 1.75 keV to 10 keV. Complementing the already installed vacuum-compatible PILATUS 1M detector used for small-angle x-ray scattering (SAXS) and grazing incidence SAXS, it is possible to access larger scattering angles. The water-cooled module is located on the goniometer arm and can be positioned from −90° to 90° with respect to the incoming beam at a distance of about 200 mm from the sample. To perform absolute scattering experiments, the linearity, homogeneity, and angular dependence of the quantum efficiency, including their relative uncertainties, have been investigated. In addition, the first results of the performance in wide-angle x-ray scattering, x-ray diffraction, and x-ray reflectometry are presented.
Development of an optimized dome-shaped magnet for rapid magnetic immunostaining
Authors: Sekino Masaki , Kuwahata Akihiro , Fujita Shunsuke , Matsuda Sachiko , Kaneko Miki , Chikaki Shinichi , Sakamoto Satoshi , Saito Itsuro , Handa Hiroshi , Kusakabe Moriaki
Published: February 2020

Magnetic immunostaining is a technique used to accelerate the antigen-antibody immunoreaction by increasing the local density of antibody on the surface of a tissue specimen using a magnetic field. The high density of antibody is achieved by applying a magnetic force to antibody-labeled ferrite beads toward the specimen. A technical challenge of using conventional magnets for this technique has been the inhomogeneous accumulation of magnetic beads on the specimen in accordance with the distribution of the magnetic field. Thus, in this study, a dome-shaped magnet that generated a strong and uniform magnetic force distribution was proposed and demonstrated. Numerical analysis was used to optimize the shape of the magnet. Analysis of the motion of magnetic beads showed that the accumulation of beads on the sample was complete within one minute and that the resulting homogeneity was sufficient for rapid and accurate immunostaining. Finally, experiments showed that the homogeneity of the bead distribution was improved by the use of a prototype dome-shaped magnet compared to conventional cylindrical magnets.
Effect of temperature on transport properties of cysteine in water
Authors: Koirala Rajendra Prasad , Bhusal Hem Prasad , Khanal Shyam P. , Adhikari Narayan Prasad
Published: February 2020

Molecular dynamics simulations have been performed to study the transport properties of the dilute solution of cysteine in water at different temperatures. Structural analysis of the system has been carried out using radial distribution functions between different atoms of the solvent and solute. The self-diffusion coefficients of the solute and solvent are estimated from the slope of the mean square displacement vs the time plot using Einstein’s equation and their binary diffusion coefficients from Darken’s relation. The temperature dependency of diffusion is demonstrated via Arrhenius plots. We have further extended our work to study the effects of the system size on diffusion and to calculate the viscosity coefficients of both the solvent and solution. The calculated values are in close agreement with the previously reported results available in literature.
Analysis of simple scattering models on the thermoelectric performance of analytical electron dispersions
Authors: Rudderham Cameron , Maassen Jesse
Published: February 2020

Recent first-principles electron–phonon scattering calculations of heavily doped semiconductors suggest that a simple DOS scattering model, wherein the electronic scattering rates are assumed to be proportional to the density-of-states, better approximates the rigorous scattering characteristics compared to the commonly used constant relaxation-time and constant mean-free-path approximations. This work investigates how the thermoelectric properties predicted with the DOS model compare to the other two scattering models, using three analytical electron dispersions (parabolic band in 3D/2D/1D, Kane band in 3D/2D/1D, and ring-shaped quartic band in 2D). Our findings show that the scattering models can lead to significant differences and can disagree about whether certain band structures can provide benefits. A constant relaxation-time is found to be always optimistic compared to a constant mean-free-path, while the DOS scattering model shows no such clear trend. Notably, the 1D parabolic band and 2D quartic band exhibit the highest power factors with the DOS model, resulting from a rapid decrease in density-of-states, and thus scattering—suggesting a possible strategy for improved thermoelectrics based on engineering band structures with sharp/discontinuous drops in density-of-states. The DOS scattering approximation also suggests that searches for materials with a delta function-like DOS (as a proxy to the transport distribution) or converged bands may yield limited benefits, due to the increase in scattering. This work highlights the importance of simple and accurate scattering models when rigorous ab initio scattering calculations are not feasible.
Exact solutions for the fluid impulse for incompressible and compressible flows
Authors: Michalak M. , Shivamoggi B. K.
Published: February 2020

In this paper, we consider the Kuz’min [Phys. Lett. A 96, 88 (1983)] and Oseledets [Russ. Math. Surv. 44, 210 (1989)] formulations for the fluid impulse density for the incompressible and compressible barotropic Euler equations. We give exact solutions for the fluid impulse density and discuss their physical significance. The compressible barotropic exact solution describes a density wave riding on a steady Burgers type vortex flow with the fluid impulse velocity component in the wave-propagation direction growing monotonically with time.
Mode transitions in nonlinear evolution of the electron drift instability in a 2D annular E × B system
Authors: Sengupta M. , Smolyakov A.
Published: February 2020

Nonlinear development of electron drift instability is studied using 2D3V azimuthal-radial Particle-in-Cell simulations of an annular Hall thruster channel of 10 cm diameter. The full 2π azimuthal domain of the annular cross section is simulated with reflecting boundary conditions at the radial boundaries. It is shown that the instability, which starts as a short length scale linear instability, undergoes a sequence of nonlinear transitions into longer wavelength modes. The transitions in the mode wavelengths are accompanied by related transitions of the magnitude of anomalous axial current. In the nonlinear stages, there is evidence of azimuthal trapping and dragging of ions by the propagating wave resulting in saturation of instability. It is demonstrated that the size of the azimuthal domain influences mode dynamics and, thereby, the anomalous cross field electron transport.
Shock-driven kinetic and diffusive mix in high-Z pusher ICF designs
Authors: Keenan Brett D. , Taitano William T. , Simakov Andrei N. , Chacón Luis , Albright Brian J.
Published: February 2020

Revolver and Double Shell Inertial Confinement Fusion capsule designs hope to achieve a robust volumetric thermonuclear burn via the use of a high-Z pusher shell filled with a cryogenic D–T fuel. Unfortunately, mix of the pusher material into the fuel (gas) may adversely impact the burn performance. Hydrodynamic instability of the metal/gas interface as the mix source is an obvious concern, but 1D effects may also be detrimental. Such effects include plasma diffusion at material interfaces, which has been the subject of numerous theoretical, computational, and experimental investigations. However, other 1D mix mechanisms may exist, which have yet to be thoroughly explored. In particular, plasma kinetic effects may drive the mix when a shock breaks out of the metal/gas interface. Using the state-of-the-art, hybrid (kinetic-ion/fluid electron), multi-ion Vlasov–Fokker–Planck code, iFP, we show that shock-driven kinetic effects can reconfigure the interface and the interfacial width subsequently grows diffusively. Finally, we consider any implications for high-Z pusher designs.
Deep learning methods for super-resolution reconstruction of turbulent flows
Authors: Liu Bo , Tang Jiupeng , Huang Haibo , Lu Xi-Yun
Published: February 2020

Two deep learning (DL) models addressing the super-resolution (SR) reconstruction of turbulent flows from low-resolution coarse flow field data are developed. One is the static convolutional neural network (SCNN), and the other is the novel multiple temporal paths convolutional neural network (MTPC). The SCNN model takes instantaneous snapshots as an input, while the MTPC model takes a time series of velocity fields as an input, and it includes spatial and temporal information simultaneously. Three temporal paths are designed in the MTPC to fully capture features in different time ranges. A weight path is added to generate pixel-level weight maps of each temporal path. These models were first applied to forced isotropic turbulence. The corresponding high-resolution flow fields were reconstructed with high accuracy. The MTPC seems to be able to reproduce many important features as well, such as kinetic energy spectra and the joint probability density function of the second and third invariants of the velocity gradient tensor. As a further evaluation, the SR reconstruction of anisotropic channel flow with the DL models was performed. The SCNN and MTPC remarkably improve the spatial resolution in various wall regions and potentially grasp all the anisotropic turbulent properties. It is also shown that the MTPC supplements more under-resolved details than the SCNN. The success is attributed to the fact that the MTPC can extract extra temporal information from consecutive fluid fields. The present work may contribute to the development of the subgrid-scale model in computational fluid dynamics and enrich the application of SR technology in fluid mechanics.
An efficient method for strongly correlated electrons in two-dimensions
Authors: Mitxelena Ion , Piris Mario
Published: February 2020

This work deals with the problem of strongly correlated electrons in two-dimensions. We give a reduced density matrix (RDM) based tool through which the ground-state energy is given as a functional of the natural orbitals and their occupation numbers. Specifically, the Piris Natural Orbital Functional 7 (PNOF7) is used for studying the 2D Hubbard model and hydrogen square lattices. The singlet ground-state is studied, as well as the doublet mixed quantum state obtained by extracting an electron from the system. Our method satisfies two-index necessary N-representability conditions of the two-particle RDM (2RDM) and guarantees the conservation of the total spin. We show the ability of PNOF7 to describe strong correlation effects in two-dimensional (2D) systems by comparing our results with the exact diagonalization, density matrix renormalization group (DMRG), and auxiliary-field quantum Monte Carlo calculations. PNOF7 overcomes variational 2RDM methods with two- and three-index positivity N-representability conditions, reducing computational cost to mean-field scaling. Consistent results are obtained for small and large systems up to 144 electrons, weak and strong correlation regimes, and many filling situations. Unlike other methods, there is no dependence on dimensionality in the results obtained with PNOF7 and no particular difficulties have been observed to converge PNOF7 away from half-filling. Smooth double occupancy of sites is obtained, regardless of the filling. Symmetric dissociation of 2D hydrogen lattices shows that long-range nondynamic correlation dramatically affects electron detachment energies. PNOF7 compares well with DMRG along the dissociation curve.
Suppression of stimulated Brillouin scattering by two perpendicular linear polarization lasers
Authors: Ban S. S. , Wang Q. , Liu Z. J. , Zheng C. Y. , He X. T.
Published: February 2020

Stimulated Brillouin scattering (SBS) is a basic problem for laser–plasma interactions. In this work, two perpendicular linear polarization lasers with different frequencies are combined to form a new beam. The polarization of the new beam varies between linear and ellipse, while the intensity remains constant. By adopting this method, a significant suppression of SBS is predicted due to the reduction in the effective wave–wave interaction lengths. Additionally, two linearly polarized beams would be easier to use in an experiment than an alternate approach using two circularly polarized beams. The suppression of SBS is modeled with a nonlinear wave–wave coupling model, and the model is verified with 1D particle-in-cell simulations.
Effect of intensified cavitation using poly(vinyl alcohol) microbubbles on spray atomization characteristics in microscale
Authors: Abbasiasl Taher , Niazi Soroush , Aghdam Araz Sheibani , Chen Hongjian , Cebeci Fevzi Çakmak , Ghorbani Morteza , Grishenkov Dmitry , Koşar Ali
Published: February 2020

In this study, cavitating flows inside a transparent cylindrical nozzle with an inner diameter of 0.9 mm were visualized, and the effect of cavitation on atomization characteristics of emerging sprays was investigated. Different patterns of cavitating flows inside the nozzle were visualized using a high-speed camera. In-house codes were developed to process the captured images to study the droplet size distribution and droplet velocity in different flow regimes. The results show that cavitating flows at the microscale have significant effects on atomization characteristics of the spray. Two working fluids, namely, water and poly(vinyl alcohol) microbubble (PVA MB) suspension, were employed. Accordingly, the injection pressures were detected as 690 kPa, 1035 kPa, and 1725 kPa for cavitation inception, supercavitation, and hydraulic flip flow regimes in the case of water, respectively. The corresponding pressures for the aforementioned patterns for PVA MB suspension were 590 kPa, 760 kPa, and 1070 kPa, respectively. At the microscale, as a result of a higher volume fraction of cavitation bubbles inside the nozzle, there is no large difference between the cavitation numbers corresponding to cavitating and hydraulic flip flows. Although the percentage of droplets with diameters smaller than 200 μm was roughly the same for both cases of water and PVA MB suspension, the Sauter mean diameter was considerably lower in the case of PVA MBs. Moreover, higher droplet velocities were achieved in the case of PVA MBs at lower injection pressures.
Hydration free energies and solvation structures with molecular density functional theory in the hypernetted chain approximation
Authors: Luukkonen Sohvi , Levesque Maximilien , Belloni Luc , Borgis Daniel
Published: February 2020

The capability of molecular density functional theory in its lowest, second-order approximation, equivalent to the hypernetted chain approximation in integral equations, to predict accurately the hydration free-energies and microscopic structure of molecular solutes is explored for a variety of systems: spherical hydrophobic solutes, ions, water as a solute, and the Mobley’s dataset of organic molecules. The successes and the caveats of the approach are carefully pinpointed. Compared to molecular simulations with the same force field and the same fixed solute geometries, the theory describes accurately the solvation of cations, less so that of anions or generally H-bond acceptors. Overall, the electrostatic contribution to solvation free-energies of neutral molecules is correctly reproduced. On the other hand, the cavity contribution is poorly described but can be corrected using scaled-particle theory ideas. Addition of a physically motivated, one-parameter cavity correction accounting for both pressure and surface effects in the nonpolar solvation contribution yields a precision of 0.8 kcal/mol for the overall hydration free energies of the whole Mobley’s dataset. Inclusion of another one-parameter cavity correction for the electrostatics brings it to 0.6 kcal/mol, that is, kBT. This is accomplished with a three-orders of magnitude numerical speed-up with respect to molecular simulations.
In vitro rumen gas production kinetics, hydrocyanic acid concentration and fermentation characteristics of fresh cassava root and feed block sulfur concentration
Authors: Dagaew Gamonmas , Cherdthong Anusorn , Wanapat Metha , Chanjula Pin
Published: February 2020

Context
Feeding ruminants with fresh cassava roots (FCR) is limited because they have a high concentration of hydrocyanic acid (HCN). Thus, it was hypothesised that receiving a feed block containing high sulfur (FBS) would reduce hydrocyanic acid (HCN) in FCR and improve rumen fermentation and nutrient digestibility in animals.

Aims
The goal of the present work was to study the influence of the ratio of FCR to rice straw (RS) together with FBS on kinetics of gas production, HCN concentration, fermentation characteristics and nutrient digestibility, using in vitro technique.

Methods
The experimental design was a 4 × 2 factorial arrangement in a completely randomised design, with three replications per treatment. Factor A was the FCR to RS ratio, which was 100:0, 60:40, 40:60 or 0:100. Factor B was sulfur, which was provided as two concentrations in FBS (2% and 4% DM). Gas production was recorded after incubation, at 0, 0.5, 1, 2, 4, 6, 8, 12, 18, 24, 48, 72 and 96 h. Fermentation liquor was collected and determined for kinetics of gas production, HCN concentration, fermentation characteristics and nutrient digestibility.

Key results
Cassava root to RS ratio influenced the cumulative gas production after 96 h. Inclusion of sulfur in the FBS at 4% increased the cumulative gas production, when compared with inclusion at 2%. The gas production from degradable fraction (b) and the rate of gas production (c) were significantly different among the treatments with different FCR:RS ratios, whereas there was no difference between using 2% and 4% sulfur in the FBS. The HCN concentration in fermentation liquor increased with an increasing proportion of FCR. Furthermore, inclusion of sulfur in the feed block at 4% reduced HCN concentration by 42.8%, when compared with inclusion at 2% (P < 0.05). Ammonia-nitrogen concentration was significantly different among the FCR:RS-ratio treatments and was reduced when the proportion of FCR was decreased (P < 0.05). In vitro digestibility was significantly increased with an increasing proportion of FCR. Increasing the proportion of FCR with 4% of sulfur in the FBS significantly increased in vitro DM digestibility, compared with 2% sulfur. Increasing the FCR:RS ratio with 4% of sulfur in the FBS increased the proportion of propionic acid (P < 0.05).

Conclusions
Using a high FCR:RS ratio (100:0 or 60:40) with 4% sulfur in the FBS enhanced kinetics of gas production, propionic molar proportion, nutrient digestibility, and HCN detoxification by rumen microbes in an in vitro trial.

Implications
An in vivo study should be encouraged to verify the results and obtain more data.
Infection with an asymptomatic virus in rice results in a delayed drought response
Authors: Encabo Jaymee R. , Macalalad-Cabral Reena Jesusa A. , Matres Jerlie Mhay K. , Coronejo Sapphire Charlene Thea P. , Jonson Gilda B. , Kishima Yuji , Henry Amelia , Choi Il-Ryong
Published: February 2020

Infection of viruses in plants often modifies plant responses to biotic and abiotic stresses. In the present study we examined the effects of Rice tungro spherical virus (RTSV) infection on drought response in rice. RTSV infection delayed the onset of leaf rolling by 1–2 days. During the delay in drought response, plants infected with RTSV showed higher stomatal conductance and less negative leaf water potential under drought than those of uninfected plants, indicating that RTSV-infected leaves were more hydrated. Other growth and physiological traits of plants under drought were not altered by infection with RTSV. An expression analysis of genes for drought response-related transcription factors showed that the expression of OsNAC6 and OsDREB2a was less activated by drought in RTSV-infected plants than in uninfected plants, further suggesting improved water status of the plants due to RTSV infection. RTSV accumulated more in plants under drought than in well-watered plants, indicating the increased susceptibility of rice plants to RTSV infection by drought. Collectively, these results indicated that infection with RTSV can transiently mitigate the influence of drought stress on rice plants by increasing leaf hydration, while drought increased the susceptibility of rice plants to RTSV.
Closer supervision in Australian general practice training: planning major system change
Authors: Ingham Gerard , Plastow Kayty , Kippen Rebecca , White Nicky
Published: February 2020

Major system change involving closer supervision of trainee GP registrars in Australia is warranted. Change management guidelines recommend involving stakeholders in developing change. The views of those involved in general practice training about current and potential supervisory practice were explored. Semi-structured interviews were conducted with a lead medical educator from nine Australian regions. Focus groups were conducted with GP supervisors and GP registrars. Transcripts from the interviews and focus groups were analysed using conventional content analysis, with themes emerging inductively from the data. The findings were that over 1–3 months, a registrar could progress from their supervisor observing all consultations through to the registrar only calling when they identify the need for help. There is strong support from registrars for this change to closer supervision, but less support from supervisors and educators. Barriers to the proposed change include high clinical demand competing with teaching capacity, inadequate payment for closer supervision and supervisors lacking skills or motivation to have a more active role in registrar supervision. If funding and logistic barriers to change are addressed, a change to a closer level of supervision is possible. A pilot study to further refine the change is indicated.
Total grazing pressure - a defining concept for extensive pastoral systems in the southern rangelands of Australia
Authors: Hacker R. B. , Sinclair K. , Waters C. M.
Published: February 2020

In Australia, particularly in the southern rangelands, large populations of native and feral herbivores (including kangaroos, goats, rabbits, pigs, donkeys and camels, depending on the location) co-exist with domestic livestock. In recent decades the concept of ‘total grazing pressure’ has been developed, and widely accepted, to denote the total forage demand of all vertebrate herbivores relative to the forage supply. This concept provides a framework within which both domestic and non-domestic species can be managed to allow commercially viable livestock production, landscape maintenance or restoration and species conservation. The concept should have relevance wherever pest animal control programs, biodiversity conservation, or commercialisation of wildlife are conducted in conjunction with extensive livestock production. The rationale for the compilation of the Special Issue is outlined.
Litter decomposition in wet and dry ecosystems of the Brazilian Cerrado
Authors: Souza e Brito Betânia Guedes , Veloso Maria das Dores Magalhães , Sarneel Judith M. , Falcão Luiz Alberto Dolabela , Ribeiro Juliana Martins , Almeida Frazão Leidivan , Fernandes Geraldo Wilson
Published: February 2020

Decomposition of plant litter is a crucial process in carbon and nutrient cycling in all ecosystems, but our understanding of drivers of this process in Brazilian Cerrado (savanna) ecosystems is limited. We determined the decomposition rate and the stabilisation factor in areas of cerrado sensu stricto and palm swamp (vereda) in Bonito de Minas, Minas Gerais, south-eastern Brazil. These two major Cerrado ecosystems differ markedly in environmental conditions, but primarily in water and soil conditions. We used the standardised Tea Bag Index method, characterised soil parameters, and microbial activity to evaluate the decomposition process between these ecosystems. We found higher decomposition rates in the palm swamp compared to cerrado sensu stricto, possibly due to higher soil temperature and humidity conditions and higher microbial biomass.
Pre-harvest management of the oriental fruit fly.
Authors: Manrakhan A.
Published: February 2020

The oriental fruit fly,
Bactrocera dorsalis
(Hendel) (Diptera: Tephritidae), is an important pest of commercial fruit and vegetables in various parts of Asia and Africa, in some South Pacific islands and in Hawaii. Commercial fruit and vegetables can be protected from this pest prior to harvest using multiple control tactics. This paper reviews measures being used and developed for pre-harvest management of
B. dorsalis
. An integrated use of monitoring and combinations of control tactics on an area-wide basis for the pest is discussed.
Dry reforming of methane in a temperature-controlled dielectric barrier discharge reactor: disclosure of reactant effect
Authors: Zhang Xuming , Wenren Yesheng , Zhou Weili , Han Jingyi , Lu Hao , Zhu Zuchao , Wu Zuliang , Cha Min Suk
Published: February 2020

Plasma-assisted dry reforming of methane has attracted much research attention because this process simultaneously utilizes greenhouse, methane and carbon dioxide, to produce hydrogen-rich syngas at a relative low temperature. Although it is generally recognized that the gas composition of reactant has great effect on the methane conversion and products distribution, systematic studies that clarify the roles that electron-induced chemistry and thermochemistry play are needed for a full understanding of reactant effect. Here, we compared the reforming performance by varying the ratio of CO2/CH4 or O2/CH4 at the similar reduced field intensity (E/N) in a temperature-controlled dielectric barrier discharge reactor to elaborate the role of electron-induced chemistry and thermo-chemistry in the dry reforming process. By conducting optical emission spectrum measurement, the enrichment of O atoms was observed at the increased CO2/CH4 or O2/CH4 ratios. At T = 293 K, methane conversion was only dependent on the electron-induced chemistry regardless of the specific reactant gas composition. At a relative high temperature condition, however, thermochemistry could become pronounce when sufficient O atoms were added into the dry reforming process. In contrast, the chemical pathways to the products were overall controlled by the thermochemistry at the tested background temperatures. Due to the conversion of carbon-based products into the carbon dioxide, the conversion of carbon dioxide was influenced by the thermochemistry when the concentration of O atoms was high. Our findings may improve the understanding of reactant effect and the designs of plasma-reformer.
Surface properties of SnO2 nanolayers prepared by spin-coating and thermal oxidation
Authors: Kwoka M , Lyson-Sypien B , Comini E , Krzywiecki M , Waczynski K , Szuber J
Published: February 2020

In this work, comparative studies of the surface morphology and surface chemistry of SnO2 nanolayers prepared by spin coating with subsequent thermal oxidation (SCTO) in the temperature range of 400–700 °C using scanning electron microscopy (SEM), atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS) methods, are presented. The SEM images show that SCTO SnO2 nanolayers contain partly connected irregular structures strongly dependent on the final oxidation temperature, with interconnected single grains of longitudinal shape and size, resulting in a flatter surface morphology with respect to the commonly used three-dimensional (3D) SnO2 thin films. In turn, AFM studies additionally confirm that SCTO SnO2 nanolayers after post-oxidation annealing at higher temperatures contain isolated grains of average lateral dimensions in the range of 20–50 nm having a rather flat surface morphology of average surface roughness defined by the root mean square factor at the level of ∼2 nm. From the XPS experimental research it can be concluded that, for our SCTO SnO2 samples, a slight surface nonstoichiometry defined by the relative [O]/[Sn] concentration at the level of 1.8–1.9 is observed, also depending on the final post-oxidation temperature, being an evident contradiction to recently published literature using x-ray diffraction data. Moreover, XPS experiments show that there is also a permanent small amount of carbon contamination present at the surface of internal grains of our SCTO SnO2 nanolayers, creating an undesired potential barrier for interactions with gaseous species when they are used as the active materials for gas sensing devices.
Entanglement-based quantum deep learning
Authors: Yang Zhenwei , Zhang Xiangdong
Published: February 2020

Classical deep learning algorithms have aroused great interest in both academia and industry for their utility in image recognition, language translation, decision-making problems and more. In this work, we have provided a quantum deep learning scheme based on multi-qubit entanglement states, including computation and training of neural network in full quantum process. In the course of training, efficient calculation of the distance between unknown unit vector and known unit vector has been realized by proper measurement based on the Greenberger–Horne–Zeilinger entanglement states. An exponential speedup over classical algorithms has been demonstrated. In the process of computation, quantum scheme corresponding to multi-layer feedforward neural network has been provided. We have shown the utility of our scheme using Iris dataset. The extensibility of the present scheme to different types of model has also been analyzed.
Membrane potentials, oxidative stress and the dispersal response of bacterial biofilms to 405 nm light
Authors: Blee J A , Roberts I S , Waigh T A
Published: February 2020

The majority of chronic infections are caused by biofilms, which have higher levels of antibiotic resistance than planktonic growth. Violet-blue 405 nm light has recently emerged as a novel bactericide, but limited studies have been conducted on its effectiveness against biofilms. We found that in response to 405 nm light both Pseudomonas aeruginosa and Bacillus subtilis biofilms exhibited cell dispersal and membrane potential hyperpolarisations. The response to 405 nm light depended on the stage of biofilm growth. The use of reactive oxygen species scavengers reduced membrane hyperpolarisation and biofilm dispersal in response to 405 nm light. This is the first time that membrane potential hyperpolarisations have been linked with photooxidative stress in bacteria and with biofilm dispersal. These results provide a new insight into the role of membrane potentials in the bacterial stress response and could be used in the development of 405 nm light based biofilm treatments.
Absorbing properties of metamaterial dihedral corner reflector
Authors: Lu Taoming , Wang Youcheng , Yang Helin , Huang Xiaojun , Zhou Yanfei , Wu Jiong
Published: February 2020

In this paper, the absorbing property of metal-cross shaped metamaterial dihedral (MCMD) and cross-cross shaped metamaterial dihedral (CCMD) with the same parameters are investigated. In TE mode, the absorptivities are 91.1% at 9.17 GHz for MCMD and 99.7% at 9.20 GHz for CCMD. For MCMD and CCMD, the absorptivities are 90.5% and 99.8% at 9.2 and 9.17 GHz respectively for the TM polarized incident wave. The results of simulation and measurement show that CCMD has better multi-band absorption performance and lower radar cross-section than MCMD. Experiments have demonstrated the reflection coefficient can be utilized to analyze the electromagnetic characteristics of dihedral corner as well. The study of dihedral corner reflector is of great importance as it is used in modeling many areas such as stealth technology, electromagnetic compatibility and target recognition.
Characterization of a composite polylactic acid-hydroxyapatite 3D-printing filament for bone-regeneration
Authors: Amnael Orozco-Díaz C , Moorehead Robert , Reilly Gwendolen C , Gilchrist Fiona , Miller Cheryl
Published: February 2020

Autologous cancellous-bone grafts are the current gold standard for therapeutic interventions in which bone-regeneration is desired. The main limitations of these implants are the need for a secondary surgical site, creating a wound on the patient, the limited availability of harvest-safe bone, and the lack of structural integrity of the grafts. Synthetic, resorbable, bone-regeneration materials could pose a viable treatment alternative, that could be implemented through 3D-printing. We present here the development of a polylactic acid-hydroxyapatite (PLA-HAp) composite that can be processed through a commercial-grade 3D-printer. We have shown that this material could be a viable option for the development of therapeutic implants for bone regeneration. Biocompatibility in vitro was demonstrated through cell viability studies using the osteoblastic MG63 cell-line, and we have also provided evidence that the presence of HAp in the polymer matrix enhances cell attachment and osteogenicity of the material. We have also provided guidelines for the optimal PLA-HAp ratio for this application, as well as further characterisation of the mechanical and thermal properties of the composite. This study encompasses the base for further research on the possibilities and safety of 3D-printable, polymer-based, resorbable composites for bone regeneration.
Unmanned aerial vehicle observations of cold venting from exploratory hydraulic fracturing in the United Kingdom
Authors: Shah Adil , Ricketts Hugo , Pitt Joseph R , Shaw Jacob T , Kabbabe Khristopher , Leen J Brian , Allen Grant
Published: February 2020

Unmanned aerial vehicle (UAV) surveys allow for rapid-response near-field sampling, downwind of emission sources, such as gas extraction sites, without the need for site access. UAVs can be used in emission source identification alongside instantaneous flux estimation. A UAV was used to sample downwind of the UK’s first and only gas extraction site to use exploratory onshore horizontal hydraulic fracturing (fracking) of shale formations, in Little Plumpton, Lancashire. In-situ calibrated UAV methane mole fraction measurements were made from a neighbouring field on five sampling days between October 2018 and February 2019, during fracking, flow-back and flow testing. Methane emissions were identified on one of the five sampling days (14 January 2019), associated with known cold venting, following fluid unloading using a nitrogen lift. A near-field Gaussian plume inversion approach was used to calculate four instantaneous fluxes on this day (from four separate intermittent UAV flight surveys) with lower and upper uncertainty bounds of between 9–80 g s−1, 23–106 g s−1, 16–82 g s−1 and 34–156 g s−1, respectively. The cold venting emissions observed on this single day were at least an order of magnitude higher than UAV methane fluxes calculated for nearby dairy farm buildings, also presented here. Identifying and quantifying these methane emission sources are important to improve the national emissions inventory and to regulate this developing UK industry.
On matrix rearrangement inequalities
Authors: Alaifari Rima , Cheng Xiuyuan , Pierce Lillian , Steinerberger Stefan
Published: February 2020

Given two symmetric and positive semidefinite square matrices

A
,
B

A, B

, is it true that any matrix given as the product of

m
m

copies of

A
A

and

n
n

copies of

B
B

in a particular sequence must be dominated in the spectral norm by the ordered matrix product

A
m

B
n

A^m B^n

? For example, is
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="double-vertical-bar upper A upper A upper B upper A upper A upper B upper A upper B upper B double-vertical-bar less-than-or-equal-to double-vertical-bar upper A upper A upper A upper A upper A upper B upper B upper B upper B double-vertical-bar question-mark">

‖
A
A
B
A
A
B
A
B
B
‖
≤
‖
A
A
A
A
A
B
B
B
B
‖
?

\begin{equation*} \| AABAABABB \| \leq \| AAAAABBBB \| ? \end{equation*}

Drury [Electron J. Linear Algebra 18 (2009), pp. 13–20] has characterized precisely which disordered words have the property that an inequality of this type holds for all matrices

A
,
B

A,B

. However, the

1
1

-parameter family of counterexamples Drury constructs for these characterizations is comprised of

3
×
3

3 \times 3

matrices, and thus as stated the characterization applies only for

N
×
N

N \times N

matrices with

N
≥
3

N \geq 3

. In contrast, we prove that for

2
×
2

2 \times 2

matrices, the general rearrangement inequality holds for all disordered words. We also show that for larger

N
×
N

N \times N

matrices, the general rearrangement inequality holds for all disordered words for most

A
,
B

A,B

(in a sense of full measure) that are sufficiently small perturbations of the identity.
Totally real flat minimal surfaces in quaternionic projective spaces
Authors: He Ling , Zhou Xianchao
Published: February 2020

In this paper, we study totally real minimal surfaces in the quaternionic projective space

H

P
n

\mathbb {H}P^n

. We prove that the linearly full totally real flat minimal surfaces of isotropy order

n
n

in

H

P
n

\mathbb {H}P^n

are two surfaces in

C

P
n

\mathbb {C}P^n

, one of which is the Clifford solution, up to symplectic congruence.
Deformation theory of contact Lie algebras as double extensions
Authors: Alvarez M. , Rodríguez-Vallarte M. , Salgado G.
Published: February 2020

The purpose of this work is to completely characterize contact Lie algebras, i.e., linear and quadratic deformations of the Heisenberg Lie algebra, by means of double extensions.
Corrigendum to “Operators with an integral representation”
Authors: Cilia Raffaella , Gutiérrez Joaquín
Published: February 2020

We make an observation that may clarify the main definition from our paper [Proc. Amer. Math. Soc. 144 (2016), pp. 5275–5290].
On non-uniqueness in mean field games
Authors: Bayraktar Erhan , Zhang Xin
Published: February 2020

We analyze an

N
+
1

N+1

-player game and the corresponding mean field game with state space

{
0
,
1
}

\{0,1\}

. The transition rate of the

j
j

th player is the sum of his control

α
j

\alpha ^j

plus a minimum jumping rate

η
\eta

. Instead of working under monotonicity conditions, here we consider an anti-monotone running cost. We show that the mean field game equation may have multiple solutions if

η
>

1
2

\eta > \frac {1}{2}

. We also prove that although multiple solutions exist, only the one coming from the entropy solution is charged (when

η
=
0

\eta =0

), and therefore resolve a conjecture of Hajek and Livesay.
On the range of a vector measure
Authors: Rodríguez José
Published: February 2020

Let

(
Ω
,
Σ
,
μ
)

(\Omega ,\Sigma ,\mu )

be a finite measure space, let

Z
Z

be a Banach space, and let

ν
:
Σ
→

Z
∗

\nu :\Sigma \to Z^*

be a countably additive

μ
\mu

-continuous vector measure. Let

X
⊆

Z
∗

X \subseteq Z^*

be a norm-closed subspace which is norming for 

Z
Z

. Write

σ
(
Z
,
X
)

\sigma (Z,X)

(resp.,

μ
(
X
,
Z
)

\mu (X,Z)

) to denote the weak (resp., Mackey) topology on 

Z
Z

(resp.,

X
X

) associated to the dual pair

⟨
X
,
Z
⟩

\langle X,Z\rangle

. Suppose that, either

(
Z
,
σ
(
Z
,
X
)
)

(Z,\sigma (Z,X))

has the Mazur property, or

(

B

X
∗

,

w
∗

)

(B_{X^*},w^*)

is convex block compact and

(
X
,
μ
(
X
,
Z
)
)

(X,\mu (X,Z))

is complete. We prove that the range of 

ν
\nu

is contained in 

X
X

if, for each

A
∈
Σ

A\in \Sigma

with

μ
(
A
)
>
0

\mu (A)>0

, the

w
∗

w^*

-closed convex hull of
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-brace StartFraction nu left-parenthesis upper B right-parenthesis Over mu left-parenthesis upper B right-parenthesis EndFraction colon upper B element-of normal upper Sigma comma upper B subset-of-or-equal-to upper A comma mu left-parenthesis upper B right-parenthesis greater-than 0 right-brace">

{

ν
(
B
)

μ
(
B
)

:

B
∈
Σ
,

B
⊆
A
,

μ
(
B
)
>
0
}

\{\frac {\nu (B)}{\mu (B)}: \, B\in \Sigma , \, B \subseteq A, \, \mu (B)>0\}

intersects 

X
X

. This extends results obtained by Freniche [Proc. Amer. Math. Soc. 107 (1989), no. 1, pp. 119–124] when

Z
=

X
∗

Z=X^*

.
Generalized moment graphs and the equivariant intersection cohomology of BXB-orbit closures in the wonderful compactification of a group
Authors: Oloo Stephen
Published: February 2020

We provide a functorial description of the torus equivariant intersection cohomology of the Borel orbit closures in the wonderful compactification of a semisimple adjoint complex algebraic group. Ours is an adaptation of the moment graph approach of Goresky, Kottwitz, and MacPherson. We first define a generalized moment graph, a combinatorial object determined by the structure of a finite collection of low-dimensional torus orbits. We then show how an algorithm of Braden and MacPherson computes the stalks of the equivariant intersection cohomology complex, producing “sheaves” on the generalized moment graph that functorially encode the equivariant intersection cohomology. Because the Braden-MacPherson algorithm uses only basic commutative algebra, this approach greatly simplifies the a priori very difficult task of computing intersection cohomology stalks. This paper extends previous work of Springer, who had computed the (ordinary) intersection cohomology Betti numbers of the Borel orbit closures in the wonderful compactification.
A trajectory map for the pressureless Euler equations
Authors: Hynd Ryan
Published: February 2020

We consider the dynamics of a collection of particles that interact pairwise and are restricted to move along the real line. Moreover, we focus on the situation in which particles undergo perfectly inelastic collisions when they collide. The equations of motion are a pair of partial differential equations for the particles’ mass distribution and local velocity. We show that solutions of this system exist for given initial conditions by rephrasing these equations in Lagrangian coordinates and then by solving for the associated trajectory map.