bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrostatic forces acting on particle image velocimetry tracer particles in a plasma actuator flow
Authors: Masati A. , Sedwick R. J.
Published: January 2018

Dusty plasma effects were investigated for the results of plasma actuator particle image velocimetry experiments. Two particle charging theories, partially collisional and fully collisional theories, are used to estimate the charge on the particles. Secondary aerodynamic forces are shown to be weak in comparison to Stokes drag, and secondary dusty plasma effects are also weak compared to the electrostatic force. It is shown that the true air velocity can be calculated by extrapolating to the 0-nm particle size. Using the difference in velocity between the air and the particles, the Stokes drag force is calculated and found to be between 1 and 200 pN depending on particle size. The electrostatic force is also calculated and found to be almost equal and opposite to Stokes drag, but the charge and electric field components cannot be separated. Based on assumptions from published simulation results, the theories are shown to be within a factor of two in predicting the charge on a particle in a high pressure plasma.
Multi-charge-state molecular dynamics and self-diffusion coefficient in the warm dense matter regime
Authors: Fu Yongsheng , Hou Yong , Kang Dongdong , Gao Cheng , Jin Fengtao , Yuan Jianmin
Published: January 2018

We present a multi-ion molecular dynamics (MIMD) simulation and apply it to calculating the self-diffusion coefficients of ions with different charge-states in the warm dense matter (WDM) regime. First, the method is used for the self-consistent calculation of electron structures of different charge-state ions in the ion sphere, with the ion-sphere radii being determined by the plasma density and the ion charges. The ionic fraction is then obtained by solving the Saha equation, taking account of interactions among different charge-state ions in the system, and ion–ion pair potentials are computed using the modified Gordon–Kim method in the framework of temperature-dependent density functional theory on the basis of the electron structures. Finally, MIMD is used to calculate ionic self-diffusion coefficients from the velocity correlation function according to the Green–Kubo relation. A comparison with the results of the average-atom model shows that different statistical processes will influence the ionic diffusion coefficient in the WDM regime.
Dust acoustic solitons and polarization force
Authors: Goswami Rajita , Bora Madhurjya P.
Published: January 2018

In this report, we present an analysis of the effect of polarization force on dust acoustic solitons with self-consistent inclusion of the polarization effect into the dust-charging model. This has been carried out considering the dependence of dust-charge number on dust potential, which is affected by the polarization force. Our analysis shows that inclusion of polarization effect into the dust-charging model results in solitons of much higher amplitudes.
Spectroscopic fast neutron transmission imaging in a treaty verification setting
Authors: Ogren K. , Nattress J. , Jovanovic I.
Published: January 2018

Measurements of the geometric configuration of objects and their material composition are needed for nuclear treaty verification purposes. We experimentally demonstrate a simple method based on monoenergetic fast neutron transmission to realize crude imaging of the geometric configuration of special nuclear material, confirm its fissionable content, and obtain information on its approximate fissile mass. In the experiment, we used monoenergetic neutrons from D(d, n)3He and T(d, n)4He reactions and a linear array of liquid scintillation detectors to perform spectroscopic neutron imaging of up to 13.7 kg of highly enriched uranium in a spherical geometry. We also show an example of detection of material diversion and confirm the presence of fissionable material based on the measurement of high-energy prompt fission neutrons, including estimating the quantity of material from the comparison of measured and predicted fission neutron emission rate. The combination of crude imaging and fissionable material detection and quantification in a simple approach may be attractive in certain treaty verification scenarios.
Large magnetocaloric effect of NdGa compound due to successive magnetic transitions
Authors: Zheng X. Q. , Xu J. W. , Shao S. H. , Zhang H. , Zhang J. Y. , Wang S. G. , Xu Z. Y. , Wang L. C. , Chen J. , Shen B. G.
Published: January 2018

The magnetic behavior and MCE property of NdGa compound were studied in detail. According to the temperature dependence of magnetization (M-T) curve at 0.01 T, two sharp changes were observed at 20 K (TSR) and 42 K (TC), respectively, corresponding to spin reorientation and FM-PM transition. Isothermal magnetization curves up to 5 T at different temperatures were measured and magnetic entropy change (ΔSM) was calculated based on M-H data. Temperature dependences of –ΔSM for a field change of 0-2 T and 0-5 T show that there are two peaks on the curves corresponding to TSR and TC, respectively. The value of the two peaks is 6.4 J/kg K and 15.5 J/kg K for the field change of 0-5 T. Since the two peaks are close, the value of –ΔSM in the temperature range between TSR and TC keeps a large value. The excellent MCE performance of NdGa compound benefits from the existence of two successive magnetic transitions.
Effect of size distribution on magnetic properties in cobalt nanowires
Authors: Xu Huanhuan , Wu Qiong , Yue Ming , Li Chenglin , Li Hongjian , Palaka Subhashini
Published: January 2018

Cobalt nanowires were synthesized by reduction of carboxylate salts of Co in 1, 2-butanediol using a solvothermal chemical process. These nanowires crystallize with the hcp structure and the growth axis is parallel to the crystallographic c-axis. The morphology of the nanowires that prepared with mechanical stirring during earlier stage of the reaction process exhibits a smaller averaged aspect ratio but narrow size distribution. The assembly of the nanowires that prepared with mechanical stirring shows almost same coercivity and remanent magnetization but 59% increase of magnetic energy product. This remarkable improvement of energy product has been further understood by micromagnetic simulations. The magnetic performance at variant temperatures of Co nanowires has also been presented. These ferromagnetic nanowires could be new ideal building blocks for permanent magnets with high performance and high thermal stability.
Structural and magnetic properties of (Co1–xNix)Cr2O4 (x = 0.5, 0.25) nanoparticles
Authors: Mohanty P. , Prinsloo A. R. E. , Doyle B. P. , Carleschi E. , Sheppard C. J.
Published: January 2018

Nanoparticles of (Co1–xNix)Cr2O4, with x = 0.5 and 0.25, were prepared utilizing the sol-gel technique, in order to investigate the effect of Ni substitution at the Co site. The crystal structure of the prepared samples was identified using X-ray diffraction. Transmission electron microscopy images indicate a non-uniform distribution in particle sizes. Temperature dependent magnetization measurements as a function of probing field demonstrate different magnetic transition temperatures to that of both the parent compounds. The magnetization as a function of applied magnetic field shows a wasp-waist like feature for (Co0.5Ni0.5)Cr2O4 nanoparticles measured at 10 K, which is absent in both NiCr2O4 and CoCr2O4. This feature diminished for other measurement temperatures below the Curie temperature and was also absent at all temperatures for the (Co0.75Ni0.25)Cr2O4 nanoparticles. X-ray photoemission spectroscopy results show that the Ni cations prefers the 3+ and Co the 2+ oxidation states, while that of Cr was found to be 3+. However, mixed oxidation states were observed for Ni and Co in both samples, which can influence the magnetic properties.
Simulation study on the spatial and temporal characteristics of focused microwave beam discharge in nitrogen
Authors: Yang Wei , Zhou Qianhong , Dong Zhiwei
Published: January 2018

This paper reports a simulation study on a focused microwave (frequency 9.4 GHz, pulse width 2.5 μs, and peak electric field 1.2 kV/cm) discharge in 200 Pa nitrogen. A one-dimensional (1D) fluid model is based on the wave equation for the microwave field propagating through the gas breakdown plasma, the continuity equations for electron, ion and neutral particle densities, and the energy balance equations for mean electron temperature, and nitrogen vibrational and translational temperatures. These equations are numerically solved in a self-consistent manner with a simplified plasma chemistry set, in which the reaction rates involving electrons are calculated from the electron energy distribution function (EEDF) using a two-term expansion method. The spatial and temporal characteristics of the focused microwave breakdown in nitrogen are demonstrated, which include the amplitude of the microwave electric field, and the densities and temperatures of the plasma components. The temporal evolution of the plasma electron density agrees reasonably well with that measured with a microwave interferometer. The spatial-temporal distributions of metastable states are discussed on the plasma chemistry and the character of mean electron temperature. The spatially integrated N2(C3) density shows similar trends with the measured temporal intensity of optical emission spectroscopy, except for a time delay of 100–300 ns. The quantitative discrepancies are explained in light of limitations of the 1D model with a two-term expansion of EEDF. The theoretical model is found to describe the gas breakdown plasma generated by focused microwave beams at least qualitatively.
Magnetic properties and magnetocaloric effects of RNiSi2 (R= Gd, Dy, Ho, Er, Tm) compounds
Authors: Zhang B. , Zheng X. Q. , Zhang Y. , Zhao X. , Xiong J. F. , Zuo S. L. , Liu D. , Zhao T. Y. , Hu F. X. , Shen B. G.
Published: January 2018

Orthorhombic CeNiSi2-type polycrystalline RNiSi2 (R=Gd, Dy, Ho, Er, Tm) compounds were synthesized and the magnetic and magnetocaloric properties were investigated in detail. The transition temperatures of RNiSi2 compounds are all in a very low temperature range (<30 K). As temperature increases, all of the compounds undergo an AFM to PM transition (GdNiSi2 at 18 K, DyNiSi2 at 25 K, HoNiSi2 at 10.5 K, ErNiSi2 at 3 K and TmNiSi2 at 3.5 K, respectively). ErNiSi2 compound shows the largest (ΔSM)max (maximal magnetic entropy change) among these compounds. The value of (ΔSM)max is 27.9 J/kgK under a field change of 0-5 T, which indicates that ErNiSi2 compound is very competitive for practical applications in low-temperature magnetic refrigeration in the future. DyNiSi2 compound shows large inverse MCE (almost equals to the normal MCE) below the TN which results from metamagenitic transition under magnetic field. Considering of the normal and inverse MCE, DyNiSi2 compound also has potential applications in low-temperature multistage refrigeration.
Tunable spin waves in diluted magnetic semiconductor nanoribbon
Authors: Lyu Pin , Zhang Jun-Yi
Published: January 2018

The spin wave excitation spectrum in diluted magnetic semiconductor (DMS) nanoribbons was calculated by taking account of the quantum confinement effect of carriers and spin waves. By introducing the boundary condition for the spin waves, we derived the spin wave dispersion using the path-integral formulation and Green's function method. It was shown that the spin wave excitation spectrum is discrete due to the confinement effect and strongly dependent on the carrier density, the magnetic ion density, and the width of the nanoribbon. When the width of the nanoribbon is beyond the typical nanoscales, the size effect on the excitation energies of the spin waves disappears in our calculation, which is in qualitative agreement with no obvious size effect observed in the as-made nanodevices of (Ga,Mn)As in this size regime. Our results provide a potential way to control the spin waves in the DMS nanoribbon not only by the carrier density and the magnetic ion density but also by the nanostructure geometry.
Control of the droplet generation by an infrared laser
Authors: Wang Zhibin , Chen Rong , Zhu Xun , Liao Qiang , Ye Dingding , Zhang Biao , He Xuefeng , Li Wei
Published: January 2018

In this work, the control of the droplet generation by a focused infrared (IR) laser with a wavelength of 1550 nm was studied, in which the liquid water and the oil with the surfactant of Span 80 were employed as the disperse and continuous phases, respectively. The characteristics of the droplet generation controlled by the laser was explored under various flow rates, laser powers and spot positions and the comparison between the cases with/without the laser was also performed. The results showed that when the laser was focused on the region away from the outlet of the liquid water inflow channel, the droplet shedding was blocked due to the IR laser heating induced thermocapillary flow, leading to the increase of the droplet volume and the cycle time of the droplet generation as compared to the case without the laser. Decreasing the continuous phase flow rate led to the increase of the droplet volume, cycle time of the droplet generation and the volume increase ratio, while increasing the disperse phase flow rate led to the increase of the droplet volume and the decrease of the cycle time and volume increase ratio. For a given flow rate ratio between the continuous and disperse phases, the increase of the flow rates decreased the volume increase ratio. In addition, it is also found that the droplet volume, the cycle time and the volume increase ratio all increased with the laser power. When the laser was focused at the inlet of the downstream channel, the droplet volume, the cycle time and the volume increase ratio were the largest. Moving the laser spot to the downstream or upstream led to the decrease of them. When the laser was focused on the outlet of the liquid water inflow channel, the generated droplet volume and cycle time of the droplet generation were even lower than the case without the laser because of the lowered viscosity. This works provides a comprehensive understanding of the characteristics of the droplet generation controlled by the laser, which is beneficial to promote the application of this optical method in the droplet based microfluidics.
Direct and indirect measurement of the magnetocaloric effect in bulk and nanostructured Ni-Mn-In Heusler alloy
Authors: Ghahremani Mohammadreza , Aslani Amir , Hosseinnia Marjan , Bennett Lawrence H. , Della Torre Edward
Published: January 2018

A systematic study of the magnetocaloric effect of a Ni51Mn33.4In15.6 Heusler alloy converted to nanoparticles via high energy ball-milling technique in the temperature range of 270 to 310 K has been performed. The properties of the particles were characterized by x-ray diffraction, electron microscopy, and magnetometer techniques. Isothermal magnetic field variation of magnetization exhibits field hysteresis in bulk Ni51Mn33.4In15.6 alloy across the martensitic transition which significantly lessened in the nanoparticles. The magnetocaloric effects of the bulk and nanoparticle samples were measured both with direct method, through our state of the art direct test bed apparatus with controllability over the applied fields and temperatures, as well as an indirect method through Maxwell and thermodynamic equations. In direct measurements, nanoparticle sample’s critical temperature decreased by 6 K, but its magnetocaloric effect enhanced by 17% over the bulk counterpart. Additionally, when comparing the direct and indirect magnetocaloric curves, the direct method showed 14% less adiabatic temperature change in the bulk and 5% less adiabatic temperature change in the nanostructured sample.
Magnetic and electrical properties in Co-doped KNbO3 bulk samples
Authors: Astudillo Jairo A. , Dionizio Stivens A. , Izquierdo Jorge L. , Morán Oswaldo , Heiras Jesús , Bolaños Gilberto
Published: January 2018

Multiferroic materials exhibit in the same phase at least two of the ferroic properties: ferroelectricity, ferromagnetism, and ferroelasticity, which may be coupled to each other. In this work, we investigated bulk materials with a nominal composition KNb0.95Co0.05O3 (KN:Co) fabricated by the standard solid-state reaction technique. X-ray diffraction analysis of the polycrystalline sample shows the respective polycrystalline perovskite structure of the KNbO3 phase with only small variation due to the Co doping. No secondary or segregated phases are observed. The values of the extracted lattice parameters are very close to those reported in the literature for KNbO3 with orthorhombic symmetry (a = 5.696 Å, b = 3.975 Å, and c = 5.721 Å) with space group Bmm2. Measurements of the electric polarization as a function of the electric field at different temperatures indicate the presence of ferroelectricity in our samples. Magnetic response of the pellets, detected by high sensitivity measurements of magnetization as a function of field, reveal weak ferromagnetic behavior in the doped sample at room temperature. Also, ferroelectric hysteresis loops were measured in a magnetic field of 1 T, applied perpendicular to the plane of the sample. Values of the remnant polarization as high as 7.19 and 7.69 μC/cm2 are obtained for 0 applied field and for 1 T, respectively; the value for the strength of the magnetoelectric coupling obtained is 6.9 %.
The reactivity of the Criegee intermediate CH3CHOO with water probed by FTMW spectroscopy
Authors: Cabezas Carlos , Endo Yasuki
Published: January 2018

The reaction of Criegee intermediates with water is one of the dominant removal mechanisms for these species in the atmosphere. The reactivity of alkyl substituted Criegee intermediates has been shown to be affected by the nature and location of the substituents. CH3CHOO, acetaldehyde oxide, can be considered as a prototypical Criegee intermediate with a single alkyl substituent to examine the conformer specific reactivity for Criegee intermediates. Pulsed Fourier-transform microwave spectroscopy has been used to probe the products resulting from the reaction between CH3CHOO and water. The hydrogen-bonded complex between CH3CHOO and water together with the reaction product, hydroxyethyl hydroperoxide, were observed in the discharged plasma of a CH3CHI2/O2/water gas mixture. The experimentally determined rotational parameters support the identification of the complex between water and the syn-CH3CHOO conformer and two conformers of hydroxyethyl hydroperoxide, produced from the anti-CH3CHOO conformer and water.
Effect of pulsed discharge on the ignition of pulse modulated radio frequency glow discharge at atmospheric pressure
Authors: Qiu Shenjie , Guo Ying , Han Qianhan , Bao Yun , Zhang Jing , Shi J. J.
Published: January 2018

A pulsed discharge is introduced between two sequential pulse-modulated radio frequency glow discharges in atmospheric helium. The dependence of radio frequency discharge ignition on pulsed discharge intensity is investigated experimentally with the pulse voltage amplitudes of 650, 850, and 1250 V. The discharge characteristics and dynamics are studied in terms of voltage and current waveforms, and spatial-temporal evolution of optical emission. With the elevated pulsed discharge intensity of two orders of magnitude, the ignition of radio frequency discharge is enhanced by reducing the ignition time and achieving the stable operation with a double-hump spatial profile. The ignition time of radio frequency discharge is estimated to be 2.0 μs, 1.5 μs, and 1.0 μs with the pulse voltage amplitudes of 650, 850, and 1250 V, respectively, which is also demonstrated by the spatial-temporal evolution of optical emission at 706 and 777 nm.
“Divide and conquer” semiclassical molecular dynamics: A practical method for spectroscopic calculations of high dimensional molecular systems
Authors: Di Liberto Giovanni , Conte Riccardo , Ceotto Michele
Published: January 2018

We extensively describe our recently established “divide-and-conquer” semiclassical method [M. Ceotto, G. Di Liberto, and R. Conte, Phys. Rev. Lett. 119, 010401 (2017)] and propose a new implementation of it to increase the accuracy of results. The technique permits us to perform spectroscopic calculations of high-dimensional systems by dividing the full-dimensional problem into a set of smaller dimensional ones. The partition procedure, originally based on a dynamical analysis of the Hessian matrix, is here more rigorously achieved through a hierarchical subspace-separation criterion based on Liouville’s theorem. Comparisons of calculated vibrational frequencies to exact quantum ones for a set of molecules including benzene show that the new implementation performs better than the original one and that, on average, the loss in accuracy with respect to full-dimensional semiclassical calculations is reduced to only 10 wavenumbers. Furthermore, by investigating the challenging Zundel cation, we also demonstrate that the “divide-and-conquer” approach allows us to deal with complex strongly anharmonic molecular systems. Overall the method very much helps the assignment and physical interpretation of experimental IR spectra by providing accurate vibrational fundamentals and overtones decomposed into reduced dimensionality spectra.
Enhanced vibronic interaction caused by local lattice symmetry lowering in the (Fe, Mg)As2 ternary system
Authors: Pishtshev A. , Rubin P.
Published: January 2018

By means of periodic density functional theory (DFT) electronic structure calculations, we investigate iron-site doping effects in a structural model of bulk FeAs2. Simulations performed within the projector augmented-wave method-Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) functional scheme reveal that the impacts of the two stoichiometric substitutions Fe → Mg and Fe → Ni are radically different with respect to the structural and electronic behavior of the dopants. In particular, unlike the Ni dopant, the Mg dopant incorporated in FeAs2 occupies a noncentral equilibrium position characterized by an off-center displacement from the reference higher-symmetry position. Analysis of the respective electron and vibrational factors allows us to explain this result in terms of the local pseudo Jahn-Teller effect (pJTE). On the basis of DFT calculations, we deduce which electron orbitals and lattice vibrational modes are appropriate for promoting the local instability at the origin of the pJTE. Quantitative evaluations of the pJTE parameters performed within the polyatomic formalism of an effective tight-binding model show that it is just the enhanced vibronic interaction in the Mg–[FeAs6] cluster that is responsible for the local lattice symmetry breaking.
Device model for pixelless infrared image up-converters based on polycrystalline graphene heterostructures
Authors: Ryzhii V. , Shur M. S. , Ryzhii M. , Karasik V. E. , Otsuji T.
Published: January 2018

We developed a device model for pixelless converters of far/mid-infrared radiation (FIR/MIR) images into near-infrared/visible (NIR/VIR) images. These converters use polycrystalline graphene layers (PGLs) immersed in the van der Waals materials integrated with a light emitting diode (LED). The PGL serves as an element of the PGL infrared photodetector (PGLIP) sensitive to the incoming FIR/MIR due to the interband absorption. The spatially non-uniform photocurrent generated in the PGLIP repeats (mimics) the non-uniform distribution (image) created by the incident FIR/MIR. The injection of the nonuniform photocurrent into the LED active layer results in the nonuniform NIR/VIR image reproducing the FIR/MIR image. The PGL and the entire layer structure are not deliberately partitioned into pixels. We analyze the characteristics of such pixelless PGLIP-LED up-converters and show that their image contrast transfer function and the up-conversion efficiency depend on the PGL lateral resistivity. The up-converter exhibits high photoconductive gain and conversion efficiency when the lateral resistivity is sufficiently high. Several teams have successfully demonstrated the large area PGLs with the resistivities varying in a wide range. Such layers can be used in the pixelless PGLIP-LED image up-converters. The PGLIP-LED image up-converters can substantially surpass the image up-converters based on the quantum-well infrared photodetector integrated with the LED. These advantages are due to the use of the interband FIR/NIR absorption and a high photoconductive gain in the GLIPs.
Communication: An improved linear scaling perturbative triples correction for the domain based local pair-natural orbital based singles and doubles coupled cluster method [DLPNO-CCSD(T)]
Authors: Guo Yang , Riplinger Christoph , Becker Ute , Liakos Dimitrios G. , Minenkov Yury , Cavallo Luigi , Neese Frank
Published: January 2018

In this communication, an improved perturbative triples correction (T) algorithm for domain based local pair-natural orbital singles and doubles coupled cluster (DLPNO-CCSD) theory is reported. In our previous implementation, the semi-canonical approximation was used and linear scaling was achieved for both the DLPNO-CCSD and (T) parts of the calculation. In this work, we refer to this previous method as DLPNO-CCSD(T0) to emphasize the semi-canonical approximation. It is well-established that the DLPNO-CCSD method can predict very accurate absolute and relative energies with respect to the parent canonical CCSD method. However, the (T0) approximation may introduce significant errors in absolute energies as the triples correction grows up in magnitude. In the majority of cases, the relative energies from (T0) are as accurate as the canonical (T) results of themselves. Unfortunately, in rare cases and in particular for small gap systems, the (T0) approximation breaks down and relative energies show large deviations from the parent canonical CCSD(T) results. To address this problem, an iterative (T) algorithm based on the previous DLPNO-CCSD(T0) algorithm has been implemented [abbreviated here as DLPNO-CCSD(T)]. Using triples natural orbitals to represent the virtual spaces for triples amplitudes, storage bottlenecks are avoided. Various carefully designed approximations ease the computational burden such that overall, the increase in the DLPNO-(T) calculation time over DLPNO-(T0) only amounts to a factor of about two (depending on the basis set). Benchmark calculations for the GMTKN30 database show that compared to DLPNO-CCSD(T0), the errors in absolute energies are greatly reduced and relative energies are moderately improved. The particularly problematic case of cumulene chains of increasing lengths is also successfully addressed by DLPNO-CCSD(T).
Elevated-temperature luminescence measurements to improve spatial resolution
Authors: Pluska Mariusz , Czerwinski Andrzej
Published: January 2018

Various branches of applied physics use luminescence based methods to investigate light-emitting specimens with high spatial resolution. A key problem is that luminescence signals lack all the advantages of high locality (i.e. of high spatial resolution) when structures with strong built-in electric field are measured. Such fields exist intentionally in most photonic structures, and occur unintentionally in many other materials. In this case, as a result of beam-induced current generation and its outflow, information that indicates irregularities, nonuniformities and inhomogeneities, such as defects, is lost. We show that to avoid nonlocality and enable truly local luminescence measurements, an elevated measurement temperature as high as 350 K (or even higher) is, perhaps surprisingly, advantageous. This is in contrast to a widely used approach, where cryogenic temperatures, or at least room temperature, are recommended. The elevated temperature of a specimen, together with the current outflow being limited by focused ion beam (FIB) milling, is shown to improve the spatial resolution of luminescence measurements greatly. All conclusions drawn using the example of cathodoluminescence are useful for other luminescence techniques.
Correcting for particle size effects on plasma actuator particle image velocimetry measurements
Authors: Masati A. , Sedwick R. J.
Published: January 2018

Particle image velocimetry (PIV) is often used to characterize plasma actuator flow, but particle charging effects are rarely taken into account. A parametric study was conducted to determine the effects of particle size on the velocity results of plasma actuator PIV experiments. Results showed that smaller particles more closely match air flow velocities than larger particles. The measurement uncertainty was quantified by deconvolving the particle image diameter from the correlation diameter. The true air velocity was calculated by linearly extrapolating to the zero-size particle diameter.
Are there conservation implications for kangaroos feeding on sea birds?
Authors: Hughes Michael , Bérengier Valériane
Published: January 2018

This research note documents an observation of a wild western grey kangaroo (Macropus fuliginosus) feeding on a dead silver gull (Chroicocephalus novaehollandiae) at Lucky Bay in the Cape Le Grand National Park on the south coast of Western Australia. Published evidence suggests that this behaviour is not unique and could be widespread in Western Australia and further afield. We consider why the kangaroo may be feeding on the dead gull and possible implications for conservation programs relying on poison meat baits to control introduced species.
Authenticity in employment relations: a theology of the workplace analysis
Authors: Tackney Charles Thomas
Published: January 2018

Authenticityis developed and deployed as a criterion variable for a theology of the workplace inquiry that combines theory and methodological development with data analysis. The goal is to show that social science method can offer an empirically valid, prophetic dimension to the study of employment and work parameters in light of religious teachings on the social question at national, organizational, or firm-specific levels. The function of a criterion variable is described, noting that the switch from a dependent variable approach introduces an open-system dynamism to social science. Authenticity is reviewed to better understand its utility as an emergent, yet verifiable, criterion outcome of prior conditions. Data analysis takes the form of Roman Catholic and Quaker social teachings identified as positive correlations or contrasts. This approach offers a rigorous method bridge between theology and allied fields for the common cause of assessing authenticity in firm, organization, and higher system functions.
Eroding support for democracy in Azerbaijan? Context and pitfalls in survey research
Authors: Sadigov Turkhan , Guliyev Farid
Published: January 2018

What determines the level of support for democracy in post-Soviet hybrid regimes? How stable is popular support for democracy, and what can explain its volatility? This article explores these questions using evidence from the European Bank of Research and Development's Life in Transition survey in Azerbaijan, where from 2010 to 2016 support for democracy suddenly fell from 60% to 28% – the lowest score in the transition region. We juxtapose social background factors with economic and political variables, and use regression analysis and contextual data. Our main argument is that citizens’ support for democracy in Azerbaijan is highly volatile and could be sensitive to major changes in sociopolitical conditions, notably, retaliation against dissent (from mid- 2012 on) and economic recession set in by the oil price downfall (2015). The instability of democracy support presents specific challenges in measuring political attitudes in hybrid regime contexts. Finally, reliability of survey data on regime-related attitudes obtained by public polling in societies with limited freedoms may be compromised due to survey design and execution issues. Fear and self-censorship prevalent among respondents also need to be addressed.
An Overview of Canadian Research Activities on Diseases Caused by Phytophthora ramorum: Results, Progress, and Challenges
Authors: Shamoun Simon Francis , Rioux Danny , Callan Brenda , James Delano , Hamelin Richard C. , Bilodeau Guillaume J. , Elliott Marianne , Lévesque C. André , Becker Elisa , McKenney Dan , Pedlar John , Bailey Karen , Brière S. C. , Niquidet Kurt , Allen Eric
Published: January 2018

International trade and travel are the driving forces behind the spread of invasive plant pathogens around the world, and human-mediated movement of plants and plant products is now generally accepted as the primary mode of their introduction, resulting in huge disturbance to ecosystems and severe socio-economic impact. These problems are exacerbated under the present conditions of rapid climatic change. We report an overview of the Canadian research activities on Phytophthora ramorum. Since the first discovery and subsequent eradication of P. ramorum on infected ornamentals in nurseries in Vancouver, British Columbia, in 2003, a research team of Canadian government scientists representing the Canadian Forest Service, Canadian Food Inspection Agency, and Agriculture and Agri-Food Canada worked together over a 10-year period and have significantly contributed to many aspects of research and risk assessment on this pathogen. The overall objectives of the Canadian research efforts were to gain a better understanding of the molecular diagnostics of P. ramorum, its biology, host-pathogen interactions, and management options. With this information, it was possible to develop pest risk assessments and evaluate the environmental and economic impact and future research needs and challenges relevant to P. ramorum and other emerging forest Phytophthora spp.
Postoperative Disability After Long Corrective Fusion to the Pelvis in Elderly Patients With Spinal Deformity
Authors: Togawa Daisuke , Hasegawa Tomohiko , Yamato Yu , Yoshida Go , Kobayashi Sho , Yasuda Tatsuya , Oe Shin , Banno Tomohiro , Arima Hideyuki , Mihara Yuki , Ushirozako Hiroki , Matsuyama Yukihiro
Published: January 2018

Study Design.

A prospective case series analysis.

Objective.

The purpose of this study was to investigate the degree of difficulty in daily activities of adult spinal deformity (ASD) patients after corrective long fusion to the pelvis, with an emphasis on bend forward activities.

Summary of Background Data.

No prospective studies have been reported regarding the postoperative impairments and their time course after long fusion in ASD patients.

Methods.

One-hundred three patients [26 men, 77 women; mean age 68 (50–82) years] who underwent corrective long fusion from the thoracic spine to the pelvis were included. As a control group, 578 volunteers [213 men, 365 women; mean age 72 (50–84)] who underwent musculoskeletal examination were included. Seven daily activities were assessed using Disability Scores (DS10), which ask patients to rate the difficulty of actions from 1 (very easy) to 10 (very difficult). The activities selected were a) gait, b) ability to trim toe nails, c) lie supine, d) perform personal hygiene, e) put on pants, f) pick up an item from the floor, and g) get down on all fours. Each of these activities were rated by all volunteers and patients at five assessment points in 2 years. Questionnaires (ODI, SRS-22, and DS10) were administered preoperatively, at discharge, 6 months, 1 year, and 2 years postoperatively. Radiographic parameters and clinical results of the control group were compared with those of the ASD patients and the patients with different upper instrumented vertebrae.

Results.

Although successful clinical results and deformity corrections were achieved, the ASD patients reported significant difficulty in b), d), e), f), and g) after the surgery (all P < 0.0001), regardless of the fusion length. The difficulty gradually improved toward 2 years but did not reach preoperative status.

Conclusion.

Activities requiring patients to bend forward were more difficult for elderly ASD patients postoperatively.

Level of Evidence: 3
Do Preoperative Corticosteroid Injections Increase the Risk for Infections or Wound Healing Problems After Spine Surgery?
Authors: Farshad Mazda , Burgstaller Jakob M. , Held Ulrike , Steurer Johann , Dennler Cyrill
Published: January 2018

Study Design.

A prospective multicenter cohort study.

Objectives.

This study evaluates the risk for surgical site infections (SSIs) or wound healing problems (WHPs) in patients who underwent corticosteroid injection before lumbar decompression surgery.

Summary of Background Data.

Corticosteroid injections are often used for the treatment of the degenerated spine. However, their well-known immunosuppressive effects could increase the risk for local infections, particularly if a surgical intervention follows the injection rapidly.

Methods.

The Swiss Lumbar Stenosis Outcome Study (LSOS), which is a prospective multicenter cohort study of patients with symptomatic lumbar spinal stenosis, was used as database. Of 743 patients, 422 patients underwent surgery and were eligible for the study. Ten patients (2.4%) were revised for either SSIs (n = 6) or WHPs (n = 4). A control group (n = 19) was constructed matched according to age, sex, diabetes, and body mass index (BMI). Odds ratios (ORs) were calculated by using a conditional logistic regression model to quantify the risk of SSI or WHP after preoperative corticosteroid injection. Subgroup analysis was performed for patients with injection within 0 to 3 months before surgery, 0 to 6 months before surgery, or any injection at all before surgery.

Results.

Within this cohort, no significant association could be found between preoperative corticosteroid injection and postoperative SSI or WHP in patients with corticosteroid injections within 0 to 3 months before surgery [OR = 0.36, 95% confidence interval (95% CI) 0.04–3.22], 0 to 6 months before surgery (OR = 0.69 95% CI 0.14–3.49), or any time before surgery (OR = 0.43, 95% CI 0.04–3.22).

Conclusion.

Within the here investigated cohort, the risk of SSIs or WHPs following lumbar spinal decompression surgery seems not highly associated with preoperative corticosteroid injections. However, the safe time interval between corticosteroid infiltrations and surgery remains unknown, should not be decreased incautiously, and is the subject of further research.

Level of Evidence: 2
Dedicated Afternoon Rounds for ICU Patients’ Families and Family Satisfaction With Care
Authors: Weber Urs , Johnson Jennifer , Anderson Nathanial , Knies Andrea K. , Nhundu Belinda , Bautista Cynthia , Huang Kevin B. , Hamza Muhammad , White Jessica , Coppola Anna , Akgün Kathleen M. , Greer David M. , Marcolini Evie G. , Gilmore Emily J. , Petersen Nils H. , Timario Nona , Poskus Kelly , Sheth Kevin N. , Hwang David Y.
Published: January 2018

Objective:

It was hypothesized that adding dedicated afternoon rounds for patients’ families to supplement standard family support would improve overall family satisfaction with care in a neuroscience ICU.

Design:

Pre- and postimplementation (pre-I and post-I) design.

Setting:

Single academic neuroscience ICU.

Patients:

Patients in the neuroscience ICU admitted for longer than 72 hours or made comfort measures only at any point during neuroscience ICU admission.

Intervention:

The on-service attending intensivist and a neuroscience ICU nursing leader made bedside visits to families to address concerns during regularly scheduled, advertised times two afternoons each week.

Measurements and Main Results:

One family member per patient during the pre-I and post-I periods was recruited to complete the Family Satisfaction in the ICU 24 instrument. Post-I respondents indicated whether they had participated in the afternoon rounds. For primary outcome, the mean pre-I and post-I composite Family Satisfaction in the ICU 24 scores (on a 100-point scale) were compared. A total of 146 pre-I (March 2013 to October 2014; capture rate, 51.6%) and 141 post-I surveys (October 2014 to December 2015; 47.2%) were collected. There was no difference in mean Family Satisfaction in the ICU 24 score between groups (pre-I, 89.2 ± 11.2; post-I, 87.4 ± 14.2; p = 0.6). In a secondary analysis, there was also no difference in mean Family Satisfaction in the ICU 24 score between the pre-I respondents and the 39.0% of post-I respondents who participated in family rounds. The mean Family Satisfaction in the ICU 24 score of the post-I respondents who reported no participation trended lower than the mean pre-I score, with fewer respondents in this group reporting complete satisfaction with emotional support (75% vs. 54%; p = 0.002), coordination of care (82% vs. 68%; p = 0.03), and frequency of communication by physicians (60% vs. 43%; p = 0.03).

Conclusions:

Dedicated afternoon rounds for families twice a week may not necessarily improve an ICU’s overall family satisfaction. Increased dissatisfaction among families who do not or cannot participate is possible.
Tripolymeric Corneal Coating Gel Versus Balanced Salt Solution Irrigation During Cataract Surgery: A Retrospective Analysis
Authors: Giardini Pietro , Hauranieh Nicola , Gatto Claudio , D'Amato Tóthová Jana
Published: January 2018

Purpose:

To compare the protective properties and ease of manipulation during cataract surgery of corneal coating with a gel (eyeDRO; AL.CHI.MI.A. S.R.L, Italy) and corneal irrigation with balanced salt solution (BSS).

Methods:

We analyzed the data of 51 patients receiving either eyeDRO or BSS during routine cataract surgery performed within a 20-day period in 2016. The selected parameters were intraoperative clarity and ease of manipulation; postoperative epithelial integrity; and patient discomfort.

Results:

Compared with BSS irrigation, eyeDRO coating significantly increased intraoperative clarity and ease of manipulation (P < 0.01). Single application was required in eyeDRO-treated eyes, whereas BSS was applied 5.3 ± 0.4 times on average (P < 0.01). Two hours postoperatively, a normal epithelium was observed in 90.0% and 60.0% of eyeDRO-coated and BSS-irrigated eyes, respectively; punctate epithelial damage was observed in 9.7% and 40.0% (P < 0.05) of eyeDRO-coated and BSS-irrigated eyes, respectively; eye irritation and foreign body sensation were experienced by 13.0% and 37.0% of eyeDRO-treated patients and by 65.0% and 100% of BSS-treated patients, respectively (P < 0.01). Twenty-four hours postoperatively, 80.0% of BSS-treated patients versus 19.0% of eyeDRO-treated patients still experienced foreign body sensation (P < 0.01).

Conclusions:

EyeDRO coating was shown to be a safer and more effective option than BSS irrigation in cataract surgery because single application provided optimal hydration and intraoperative clarity during the entire surgery, better preserved the corneal epithelium, and offered postoperative comfort to the patient.
Implementing a Process to Measure Return on Investment for Nursing Professional Development
Authors: Garrison Elisabeth , Beverage Jodie
Published: January 2018

Return on investment (ROI) is one way to quantify the value that nursing professional development brings to the organization. This article describes a process to begin tracking ROI for nursing professional development. Implementing a process of tracking nursing professional development practitioners’ ROI increased awareness of the financial impact and effectiveness of the department.
Knowledge, Practices, and Barriers to HIV Preexposure Prophylaxis Prescribing Among Washington State Medical Providers
Authors: Wood Brian R. , McMahan Vanessa M. , Naismith Kelly , Stockton Jonathan B. , Delaney Lori A. , Stekler Joanne D.
Published: January 2018

Background

We aimed to assess HIV preexposure prophylaxis (PrEP) awareness and prescribing practices among Washington State medical providers from diverse professional disciplines and practice types.

Methods

In May 2016, we administered an anonymous online survey to licensed medical practitioners who provide primary, longitudinal, walk-in, emergency, obstetric, gynecologic, sexually transmitted infection, or family planning care.

Results

Of 735 eligible providers, 64.8% had heard of PrEP. Younger providers and providers with a doctor of medicine degree were more likely to be aware of PrEP compared with older providers (P = 0.0001) and providers of other training backgrounds (advanced registered nurse practitioner, doctor of osteopathic medicine, or physician assistant; P = 0.04). Among providers aware of PrEP, most frequent reported concerns about prescribing were adherence (46.0%) and costs (42.9%). Providers felt very (20.1%) or somewhat (33.8%) comfortable discussing PrEP overall, but very (26.8%) or somewhat (44.7%) uncomfortable discussing cost and insurance issues. The 124 PrEP prescribers reported a median of 2 (range, 1–175; total, 1142) patients prescribed PrEP. Prior authorizations and insurance denials had prevented prescriptions for 28.7% and 12.1% of prescribers, respectively.

Conclusions

Interventions to improve PrEP access should include education to inform medical providers about PrEP, with particular attention to provider types less likely to be aware. Continued efforts to eliminate cost and insurance barriers and educate providers regarding financial resources would help improve PrEP access.
Characteristics Associated With Delivery of an Infant With Congenital Syphilis and Missed Opportunities for Prevention—California, 2012 to 2014
Authors: Biswas Hope H. , Chew Ng Rilene A. , Murray Erin L. , Chow Joan M. , Stoltey Juliet E. , Watt James P. , Bauer Heidi M.
Published: January 2018

Background

Congenital syphilis (CS), the transmission of Treponema pallidum from mother to fetus during pregnancy, can cause adverse birth outcomes. In 2012 to 2014, the CS rate in California increased more than 200% from 6.6 to 20.3 cases per 100,000 live births. Our objectives were to identify characteristics associated with delivering an infant with CS and missed opportunities for prevention among syphilis-infected pregnant women in California.

Methods

We linked California Department of Public Health syphilis surveillance records from women aged 15 to 45 years—diagnosed from March 13, 2012, to December 31, 2014—to birth records. We compared characteristics among mothers who delivered an infant with CS (CS mothers) with mothers who delivered an infant without CS (non-CS mothers) by using χ2 or Fisher exact tests. To visualize gaps in prevention among syphilis-infected pregnant women, we constructed a CS prevention cascade, a figure that shows steps to prevent CS.

Results

During the selected period, 2498 women were diagnosed as having syphilis, and 427 (17%) linked to birth records; 164 (38%) were defined as CS mothers and 263 (62%) as non-CS mothers. Mothers with CS were more likely than non-CS mothers to have their first prenatal care visit in the third trimester. High proportions of mothers in both groups reported high-risk sexual behaviors, methamphetamine use, or incarceration (13%–29%). The CS prevention cascade showed decrements of 5% to 11% in prenatal care receipt, testing, and treatment steps; only 62% of potential CS births were prevented.

Conclusions

Multifaceted efforts are needed to address gaps in the CS prevention cascade and reduce CS cases in California.