bluuebunny/crossref_metadata_2025 huggingface dataset:
Amidoxime-functionalized hydrothermal carbon materials for uranium removal from aqueous solution
Authors: Zhang Zhibin , Dong Zhimin , Dai Ying , Xiao Saijin , Cao Xiaohong , Liu Yunhai , Guo Weihua , Luo Mingbiao , Le Zhanggao
Published: October 2016

Amidoxime-functionalized hydrothermal carbon (AO-HTC) has been synthesized and applied to adsorb U(vi) from aqueous solutions, exhibiting a high selectivity above 60% for a wide pH range from 1.0 to 5.0.
In situ synthesis of molybdenum oxide@N-doped carbon from biomass for selective vapor phase hydrodeoxygenation of lignin-derived phenols under H2atmosphere
Authors: Xu Lujiang , Han Zheng , Zhang Ying , Fu Yao
Published: October 2016

We report a simple, green method to prepare molybdenum oxide@N-doped carbon (MoOx@NC)via in situpyrolysis of molybdenum precursor preloaded cellulose and demonstrate its catalytic performance for vapor phase HDO of lignin-derived phenols.
Microfluidic fabrication of composite hydrogel microparticles in the size range of blood cells
Authors: Pittermannová A. , Ruberová Z. , Zadražil A. , Bremond N. , Bibette J. , Štěpánek F.
Published: October 2016

The fabrication of alginate hydrogel microparticles with embedded liposomes and magnetic nanoparticles for radiofrequency controlled release of encapsulated chemical cargo was demonstrated.
Large size nitrogen-doped graphene-coated graphite for high performance lithium-ion battery anode
Authors: Liu Xiaoxu , Liu Erjia , Chao Dongliang , Chen Liang , Liu Shikun , Wang Jing , Li Yao , Zhao Jiupeng , Kang Yong-Mook , Shen Zexiang
Published: October 2016

A new nitrogen-doped graphene-coated graphite anode achieved a high reversible capacity, surpassing the theoretical value for graphite. The reported scalable synthesis method may also be applied to other anode systems.
Systematic understanding of the potential manganese-adsorption components of a screened Lactobacillus plantarum CCFM436
Authors: Tong Yanjun , Wang Gang , Zhang Qiuxiang , Tian Fengwei , Liu Xiaoming , Zhao Jianxin , Zhang Hao , Chen Wei
Published: October 2016

Manganese (Mn) is a toxic heavy metal that has a variety of adverse effects on human health under excess exposure.
Highly active Co–Mo–C/NRGO composite as an efficient oxygen electrode for water–oxygen redox cycle
Authors: Liu Chun-Hui , Tang Yu-Jia , Wang Xiao-Li , Huang Wei , Li Shun-Li , Dong Long-Zhang , Lan Ya-Qian
Published: October 2016

A metal/metal carbide-based composite (Co–Mo–C@NRGO-1) was synthesized using Co-doped polyoxometalate/conductive polymer/graphene precursors (Co-PCG) as an electrocatalyst for the water–oxygen redox cycle.
One-step electrodeposition of a nickel cobalt sulfide nanosheet film as a highly sensitive nonenzymatic glucose sensor
Authors: Cao Xiaoqin , Wang Kunyang , Du Gu , Asiri Abdullah M. , Ma Yongjun , Lu Qun , Sun Xuping
Published: October 2016

An electrodeposited nickel cobalt sulfide nanosheet film acts as a nonenzymatic glucose sensor with wide linear response range of 0.001–3 mM, low detection limit of 0.12 μM, high sensitivity of 3291.5 μA mM−1 cm−2, as well as good selectivity and long-term stability.
Lysosome-oriented, dual-stage pH-responsive polymeric micelles for β-lapachone delivery
Authors: Zhou Yinjian , Dong Ying , Huang Gang , Wang Yiguang , Huang Xiaonan , Zhang Fayun , Boothman David A. , Gao Jinming , Liang Wei
Published: October 2016

This lysosome-oriented, dual-stage UPS polymeric system achieves drug targeting and controlled release.
High‐speed error‐free wireless data transmission using a terahertz resonant tunnelling diode transmitter and receiver
Authors: Diebold S. , Nishio K. , Nishida Y. , Kim J.‐Y. , Tsuruda K. , Mukai T. , Fujita M. , Nagatsuma T.
Published: October 2016

An error‐free wireless transmission of a 9 Gbit/s on–off keying modulated signal as well as a 4 k video signal is demonstrated using resonant tunnelling diodes as active elements in both the transmitter and the receiver. The employed system and the modulation scheme enabling the high data rate are discussed.
Robust tracking controller for SEPIC drivers
Authors: Ablay G.
Published: October 2016

The non‐minimum phase, non‐linear nature of the SEPIC (single‐ended primary inductor converter) makes it very difficult to get robust operating conditions under load variations. Sliding‐mode control method is utilised to design a robust controller for tracking control of SEPIC converters for various applications. The implementation of the method is illustrated with the use pulse‐width modulation comparators in the control loop to preclude the risk of modulator saturation and to ease the operations. The performance of the SEPIC converter is investigated through numerical simulation and analogue electronics implementation to show the validity, robustness and feasibility of the proposed controller.
Design and actualisation of the improved Jakes fading channel
Authors: Liang Kuo‐hsien , Lo Jenn‐Yuan , Weng Wan‐de
Published: October 2016

Based on the original Jakes model, the authors have proposed a new design for an inexpensive fading channel simulator that can be easily actualised with fewer low‐frequency oscillators than that used in existing structures. The major modifications from the original Jakes model include the generation of path gains under an improved distribution, and presetting the arrival angles and initial phases to be zero. These modifications not only reduce the hardware cost of the channel simulator, but also provide better statistic properties than the model proposed by Zheng and Xiao. Specifically, the improved Jakes fading channel model presented in this study needs only eight low‐frequency oscillators. Simulation results have demonstrated that the proposed design exhibits improved first‐order and second‐order statistical properties.
Uplink design in VLC systems with IR sources and beam steering
Authors: Alresheedi Mohammed T. , Hussein Ahmed Taha , Elmirghani Jaafar M.H.
Published: October 2016

The need for high‐speed local area networks to meet the recent developments in multimedia and video transmission applications has recently focused interest on visible light communication (VLC) systems. Although VLC systems provide lighting and communications simultaneously from light emitting diodes (LEDs), LEDs, the uplink channel design in such a system is a challenging task. In this study, the authors propose a solution in which the uplink challenge in indoor VLC is resolved by the use of an infrared (IR) link. The authors introduce a novel fast adaptive beam steering IR system (FABS‐IR) to improve the uplink performance at high data rates while providing security for applications. The goal of the authors’ proposed system is to enhance the received optical power signal, speed up the adaptation process and mitigate the channel delay spread when the system operates at a high transmission rate. The channel delay spread is minimised from 0.22 ns given by hybrid diffuse IR link to almost 0.07 ns. At 2.5 Gb/s, the authors’ results show that the imaging FABS‐IR system accomplished about 11.7 dB signal to noise ratio in the presence of multipath dispersion, receiver noise and transmitter mobility.
Complementary M‐ary orthogonal spreading OFDM architecture for HF communication link
Authors: Zhang Zhenyu , Tian Fengchun , Zeng Fanxin , He Shibiao , Xuan Guixin
Published: October 2016

A complementary M‐ary orthogonal spreading (CMOS) architecture with orthogonal frequency division multiplexing (OFDM) is proposed to improve performance of bit‐error rate (BER) and spectrum efficiency for high frequency (HF) communications. The CMOS‐OFDM architecture is based on orthogonal complementary pairs with their central elements being zero. It is well known that complementary pairs theoretically reduce peak‐to‐mean envelope power ratio (PMEPR) of OFDM due to their ideal aperiodic auto‐correlation properties. However, many practical OFDM applications, such as HF OFDM and IEEE 802.11, require that no data should be modulated to direct current (DC) subcarrier, which will destroy ideal properties of traditional complementary pairs and hence increase their PMEPRs. Compared with traditional complementary pairs, the proposed zero‐centre complementary pairs (ZCCPs) in CMOS‐OFDM architecture may maintain ideal properties and hence be more suitable for OFDM systems as long as zero element in the centre is modulated to DC subcarrier. The corresponding simulation results and numerical analyses over the HF fading channel modelled by ITU‐R F.1487 are provided. Different from the previous researches on HF OFDM systems, the proposed HF CMOS‐OFDM architecture using the constructed ZCCPs not only possesses excellent BER performance, but also may firmly resist PMEPR to 3 dB or near to 3 dB.
Multilinear Laplacian discriminant analysis for gait recognition
Authors: Chhatrala Risil , Jadhav Dattatray V.
Published: October 2016

The extraction of discriminative features in presence of covariates for robust human gait recognition is a challenging task. The effect of covariate can be modelled as unknown feature contamination problem resulting in the conversion of useful or relevant feature into irrelevant one. This study presents new gait representation and recognition technique. The new technique represents gait features based on the Gabor function and discrete cosine transform of binary silhouettes. It is called as Gabor cosine feature, which represents binary gait video sequence as third order tensor. The discrimination capability of the extracted gait features has been enhanced using a new multilinear Laplacian discriminant analysis (MLDA). MLDA exploits benefit of Laplacian weighted scatter difference instead of simple scatter difference, generalised Rayleigh quotient as a class separability measure. The feasibility and performance of the proposed scheme has been evaluated using USF, CASIA, OU‐ISIR dataset. The experimental results show competitive performance in comparison with conventional gait recognition schemes.
Dynamics of the fractional‐order chaotic PMSG, its stabilisation using predictive control and circuit validation
Authors: Borah Manashita , Roy Binoy K.
Published: October 2016

This work focuses on two prime objectives. The first is to detect chaos in the fractional‐order model of a permanent magnet synchronous generator (PMSG) and the second is to suppress chaos using a novel predictive control scheme in the fractional order sense. The main contributions of the work, therefore, lie in discovering the minimum commensurate order for which chaos exists in the fractional‐order PMSG (FOPMSG), studying its dynamical behaviour ranging from Hopf bifurcation to stability analysis and the proposal of a single‐state predictive controller to stabilise the chaotic FOPMSG in both commensurate as well as incommensurate orders. The proposal of predictive controller for controlling chaos in a fractional‐order variable‐speed drive is a novel attempt. Lower control effort, effectiveness, simplicity in design and application, convenience in inclusion of non‐linearity, etc. highlight the promising potential of the proposed predictive control scheme. Circuit implementation results which are in good qualitative agreement with that of simulated results, confirm that the work attains the objectives successfully.
MEMS‐based nanoreactor for in situ analysis of solid–gas interactions inside the transmission electron microscope
Authors: Pérez Garza Hector Hugo , Morsink Diederik , Xu Jeff , Sholkina Mariya , Pivak Yevheniy , Pen Merijn , van Weperen Sander , Xu Qiang
Published: October 2016

A nanoreactor‐based system for in situ analysis of solid–gas interactions inside the transmission electron microscope, referred to as the ‘climate system’, is introduced here. The latter uses an micro‐electro mechanical systems (MEMS)‐based device as a multi‐functional sample carrier and microsized laboratory for simultaneous heating and gas experiments. To assemble the nanoreactor, two chips are sandwiched together to form a minimised chemical reaction chamber. The bottom chip contains a four‐point‐probe microheater, which controls and introduces the heating environment (up to 1300°C) around the sample. Similarly, it contains the spacers that define the height of the gas chamber. The top chip confines the gas in the microchamber while isolating it from the external environment. Both chips contain electron transparent windows that allow the electron beam to pass through for in situ imaging. The sample can be deposited or prepared directly on the windows, which are made of silicon nitride and can sustain pressures up to 1.5 bar and high temperatures while ensuring low background atomic resolution imaging.
Influence of substrate on structural properties and photocatalytic activity of TiO2 films
Authors: Pan Dong , Fan Haibo , Li Zan , Wang Siyi , Huang Yinhao , Jiao Yang , Yao Hebao
Published: October 2016

Titanium dioxide (TiO2) thin films were successfully grown on glass (TiO2/glass) and fluorine tin oxide (TiO2/FTO) substrates by using radio frequency magnetron sputtering. The as‐prepared films were characterised and compared by X‐ray diffraction, scanning electron microscopy, atomic force microscopy, ultraviolet–visible spectroscopy and photocatalytic test. It was found that the film deposited on FTO has better crystallinity, rougher superficial morphology, narrower optical bandgap and higher photocatalytic efficiency. The relationship between the factors and the photocatalytic performance has been analysed. Besides, it has been found that the internal electric field developed at the interface of TiO2/FTO may also play a positive effect on the improvement of the photocatalytic efficiency.
Improvement of short channel performance of junction‐free charge trapping 3D NAND flash memory
Authors: Gupta Deepika , Vishvakarma Santosh K.
Published: October 2016

This work investigates the effect of channel engineering on the short channel performance of considered sub‐20‐nm 3D NAND flash memory. Here, the threshold voltage roll‐off (ΔVth), subthreshold swing and drain induced barrier lowering metrics is studied to evaluate the short channel effects (SCEs) for the examined device. The effect of variation in doping density on SCEs of proposed channel engineered NAND flash memory is also studied. Based on the observation, a thin layer of high doping concentration in the centre of the channel, covering 25% of channel area, has been found to improve the SCE of NAND flash memory compared with the device with uniform channel doping while maintaining sufficient drive current.
Homing vector automata
Authors: Salehi Özlem , Cem Say A. C. , D’Alessandro Flavio
Published: October 2016

We introduce homing vector automata, which are finite automata augmented by a vector that
is multiplied at each step by a matrix determined by the current transition, and have to
return the vector to its original setting in order to accept the input. The computational
power and properties of deterministic, nondeterministic, blind, non-blind, real-time and
one-way versions of these machines are examined and compared to various related types of
automata. A generalized version of the Stern−Brocot encoding method, suitable for representing strings on
arbitrary alphabets, is also developed.
Effect of the surface charge distribution on the fluid phase behavior of charged colloids and proteins
Authors: Blanco Marco A. , Shen Vincent K.
Published: October 2016

A generic but simple model is presented to evaluate the effect of the heterogeneous surface charge distribution of proteins and zwitterionic nanoparticles on their thermodynamic phase behavior. By considering surface charges as continuous “patches,” the rich set of surface patterns that is embedded in proteins and charged patchy particles can readily be described. This model is used to study the fluid phase separation of charged particles where the screening length is of the same order of magnitude as the particle size. In particular, two types of charged particles are studied: dipolar fluids and protein-like fluids. The former represents the simplest case of zwitterionic particles, whose charge distribution can be described by their dipole moment. The latter system corresponds to molecules/particles with complex surface charge arrangements such as those found in biomolecules. The results for both systems suggest a relation between the critical region, the strength of the interparticle interactions, and the arrangement of charged patches, where the critical temperature is strongly correlated to the magnitude of the dipole moment. Additionally, competition between attractive and repulsive charge–charge interactions seems to be related to the formation of fluctuating clusters in the dilute phase of dipolar fluids, as well as to the broadening of the binodal curve in protein-like fluids. Finally, a variety of self-assembled architectures are detected for dipolar fluids upon small changes to the charge distribution, providing the groundwork for studying the self-assembly of charged patchy particles.
Plasma-resistivity-induced strong destabilization of the kinetic resistive wall mode
Authors: Yanovskiy V. V.
Published: October 2016

On the example of the plasma and mode parameters relevant, e.g., to the experiments on the rotational stabilization of resistive wall modes (RWMs) reported in Reimerdes et al. [Phys. Rev. Lett. 98, 055001 (2007)], it is shown that the plasma resistivity can have a strong impact on the stability of RWMs. The stability criteria for kinetic RWMs derived in Hu and Betti [Phys. Rev. Lett. 93, 105002 (2004)] has been complemented by the restriction on the maximum mode damping rate.
Magnetorotational instability of weakly ionized and magnetized electron-positron-ion plasma
Authors: Mehdian H. , Hajisharifi K. , Azadnia F. , Tajik-Nezhad S.
Published: October 2016

The magnetorotational instability in a differential rotating weakly ionized and magnetized plasma consisting of electron, positron, ion, and neutral particles has been investigated by using the multi-fluid model. Satisfying the current neutrality and homogeneity of the system in the equilibrium state by assuming the same unperturbed angular velocity for charge species and neutrals, the general local dispersion relation (DR) has been derived by taking into account the collision effects. By analytical examination of the obtained DR in the arbitrary and high frequency regimes, the instability conditions have been found in which the presence of light positive species (positrons) plays an important role in the instability criteria. Moreover, numerical investigation shows the broadening of instability range as well as increasing the maximum growth rate of instability (especially for the small number density ratio of light to heavy positive species) in the presence of positrons. The obtained results of the present investigation will greatly contribute to the understanding of the particles' dynamics as well as dissipation mechanism in some astrophysical environments, such as the region of accretion disks surrounding the central of black holes and protoplanetary disks.
Coverage-dependent structural phase transformations in the adsorption of pentacene on an aperiodically modulated Cu film
Authors: Lahti M. , Pussi K. , Smerdon J. A. , Young K. M. , Sharma H. R. , McGrath R.
Published: October 2016

Surface ordering of pentacene molecules adsorbed on an aperiodic Cu surface has been studied with density functional theory (DFT) and scanning tunnelling microscopy as a function of coverage. Below 0.73 ML (5.3 × 1013 molecules cm−2), the adsorbate structure is row-like with the molecular axes aligned with the rows in the Cu structure. Between this coverage and 1 ML (7.3 × 1013 molecules cm−2), a structural phase with a checkerboard structure is seen. At this coverage region, the molecules are very close to each other which leads to unusual bending. At higher coverages, a further phase transition to a high-density row structure is seen for most of the film. DFT with van der Waals functionals is employed to study how the molecule-molecule and molecule-surface interactions evolve as a function of coverage.
Preparation of a selected high vibrational energy level of isolated molecules
Authors: Perreault William E. , Mukherjee Nandini , Zare Richard N.
Published: October 2016

Stark induced adiabatic Raman passage (SARP) allows us to prepare an appreciable concentration of isolated molecules in a specific, high-lying vibrational level. The process has general applicability, and, as a demonstration, we transfer nearly 100 percent of the HD (v = 0, J = 0) in a supersonically expanded molecular beam of HD molecules to HD (v = 4, J = 0). This is achieved with a sequence of partially overlapping nanosecond pump (355 nm) and Stokes (680 nm) single-mode laser pulses of unequal intensities. By comparing our experimental data with our theoretical calculations, we are able to draw two important conclusions: (1) using SARP a large population (>1010 molecules per laser pulse) is prepared in the (v = 4, J = 0) level of HD and (2) the polarizability α00,40 (≅0.6 × 10−41 C m2 V−1) for the (v = 0, J = 0) to (v = 4, J = 0) Raman overtone transition is only about five times smaller than α00,10 for the (v = 0, J = 0) to (v = 1, J = 0) fundamental Raman transition. Moreover, the SARP process selects a specific rotational level in the vibrational manifold and can prepare one or a phased linear combination of magnetic sublevels (M states) within the selected vibrational-rotational level. This capability of preparing selected, highly excited vibrational levels of molecules under collision-free conditions opens new opportunities for fundamental scattering experiments.
Basic noise mechanisms of heat-assisted-magnetic recording
Authors: Vogler Christoph , Abert Claas , Bruckner Florian , Suess Dieter , Praetorius Dirk
Published: October 2016

Heat-assisted magnetic recording (HAMR) is expected to be a key technology to significantly increase the areal storage density of magnetic recording devices. At high temperatures, thermally induced noise becomes a major problem, which must be overcome in order to reliably write magnetic bits with narrow transitions. We propose an elementary model based on the effective recording time window (ERTW) to compute the switching probability of bits during HAMR. With few assumptions, this analytical model allows to gain deeper insights into basic noise mechanisms, like AC and DC noise. Finally, we discuss strategies to reduce noise and to increase the areal storage density of both bit-patterned and granular media.
Some remarks on the nonlinear Schrödinger equation with fractional dissipation
Authors: Darwich Mohamad , Molinet Luc
Published: October 2016

We consider the Cauchy problem for the L2-critical focussing nonlinear Schrödinger equation with a fractional dissipation. According to the order of the fractional dissipation, we prove the global existence or the existence of finite time blowup dynamics with the log-log blow-up speed for ∇u(t)L2.
Determination of plasma pinch time and effective current radius of double planar wire array implosions from current measurements on a 1-MA linear transformer driver
Authors: Steiner Adam M. , Yager-Elorriaga David A. , Patel Sonal G. , Jordan Nicholas M. , Gilgenbach Ronald M. , Safronova Alla S. , Kantsyrev Victor L. , Shlyaptseva Veronica V. , Shrestha Ishor , Schmidt-Petersen Maximillian T.
Published: October 2016

Implosions of planar wire arrays were performed on the Michigan Accelerator for Inductive Z-pinch Experiments, a linear transformer driver (LTD) at the University of Michigan. These experiments were characterized by lower than expected peak currents and significantly longer risetimes compared to studies performed on higher impedance machines. A circuit analysis showed that the load inductance has a significant impact on the current output due to the comparatively low impedance of the driver; the long risetimes were also attributed to high variability in LTD switch closing times. A circuit model accounting for these effects was employed to measure changes in load inductance as a function of time to determine plasma pinch timing and calculate a minimum effective current-carrying radius. These calculations showed good agreement with available shadowgraphy and x-ray diode measurements.
Characterization of pure and mixed Ar, Kr and Xe gas jets generated by different nozzles and a study of X-ray radiation yields after interaction with a sub-ps laser pulse
Authors: Schultz K. A. , Kantsyrev V. L. , Safronova A. S. , Moschella J. J. , Wiewior P. , Shlyaptseva V. V. , Weller M. E. , Petkov E. E. , Shrestha I. K. , Stafford A. , Cooper M. C.
Published: October 2016

Gas jets accelerated through a linear supersonic and a conical nozzle, comprising a monomer/cluster mix, were characterized at UNR using a Mach-Zehnder type interferometer and Rayleigh scattering. A comparison of the two nozzle types is presented, showing that the linear nozzle produces gas jets of an order of magnitude denser than the conical nozzle. The linear gas jets of Ar, Kr, and Xe as well as triple mixtures with different percentages of each of the aforementioned gases were characterized. The densest gas jets used Ar as the target gas, while the least dense jets came from Kr. Cluster radii of the pure gases were measured, and Xe gas jets were found to produce the largest gas clusters. A study of X-ray generation by gas jet-laser plasma was performed at the UNR Leopard laser (1.057 μm, 350 fs, ∼1019 W/cm2) on the linear nozzle. The gas jets were irradiated with a high-intensity sub-ps laser pulse. An absolute X-ray output of the laser-gas jet interactions measured by the calibrated PCDs is presented and show that triple mixtures of Xe, Kr, and Ar each exhibited a higher X-ray yield compared to the pure gases. A strong anisotropy of X-ray radiation with respect to laser beam polarization direction is observed in all the gas jets. In fact, this anisotropy is different in three spectral regions (>1.4, 3.5 and 9 keV).
A non-LTE analysis of high energy density Kr plasmas on Z and NIF
Authors: Dasgupta A. , Clark R. W. , Ouart N. , Giuliani J. , Velikovich A. , Ampleford D. J. , Hansen S. B. , Jennings C. , Harvey-Thompson A. J. , Jones B. , Flanagan T. M. , Bell K. S. , Apruzese J. P. , Fournier K. B. , Scott H. A. , May M. J. , Barrios M. A. , Colvin J. D. , Kemp G. E.
Published: October 2016

Multi-keV X-ray radiation sources have a wide range of applications, from biomedical studies and research on thermonuclear fusion to materials science and astrophysics. The refurbished Z pulsed power machine at the Sandia National Laboratories produces intense multi-keV X-rays from argon Z-pinches, but for a krypton Z-pinch, the yield decreases much faster with atomic number ZA than similar sources on the National Ignition Facility (NIF) laser at the Lawrence Livermore National Laboratory. To investigate whether fundamental energy deposition differences between pulsed power and lasers could account for the yield differences, we consider the Kr plasma on the two machines. The analysis assumes the plasma not in local thermodynamic equilibrium, with a detailed coupling between the hydrodynamics, the radiation field, and the ionization physics. While for the plasma parameters of interest the details of krypton's M-shell are not crucial, both the L-shell and the K-shell must be modeled in reasonable detail, including the state-specific dielectronic recombination processes that significantly affect Kr's ionization balance and the resulting X-ray spectrum. We present a detailed description of the atomic model, provide synthetic K- and L-shell spectra, and compare these with the available experimental data from the Z-machine and from NIF to show that the K-shell yield behavior versus ZA is indeed related to the energy input characteristics. This work aims at understanding the probable causes that might explain the differences in the X-ray conversion efficiencies of several radiation sources on Z and NIF.
On the Weyl and Ricci tensors of Generalized Robertson-Walker space-times
Authors: Mantica Carlo Alberto , Molinari Luca Guido
Published: October 2016

We prove theorems about the Ricci and the Weyl tensors on Generalized Robertson-Walker space-times of dimension n ≥ 3. In particular, we show that the concircular vector introduced by Chen decomposes the Ricci tensor as a perfect fluid term plus a term linear in the contracted Weyl tensor. The Weyl tensor is harmonic if and only if it is annihilated by Chen’s vector, and any of the two conditions is necessary and sufficient for the Generalized Robertson-Walker (GRW) space-time to be a quasi-Einstein (perfect fluid) manifold. Finally, the general structure of the Riemann tensor for Robertson-Walker space-times is given, in terms of Chen’s vector. In n = 4, a GRW space-time with harmonic Weyl tensor is a Robertson-Walker space-time.
Implementing an accurate and rapid sparse sampling approach for low-dose atomic resolution STEM imaging
Authors: Kovarik L. , Stevens A. , Liyu A. , Browning N. D.
Published: October 2016

While aberration correction for scanning transmission electron microscopes (STEMs) dramatically increased the spatial resolution obtainable in the images of materials that are stable under the electron beam, the practical resolution of many STEM images is now limited by the sample stability rather than the microscope. To extract physical information from the images of beam sensitive materials, it is becoming clear that there is a critical dose/dose-rate below which the images can be interpreted as representative of the pristine material, while above it the observation is dominated by beam effects. Here, we describe an experimental approach for sparse sampling in the STEM and in-painting image reconstruction in order to reduce the electron dose/dose-rate to the sample during imaging. By characterizing the induction limited rise-time and hysteresis in the scan coils, we show that a sparse line-hopping approach to scan randomization can be implemented that optimizes both the speed of the scan and the amount of the sample that needs to be illuminated by the beam. The dose and acquisition time for the sparse sampling is shown to be effectively decreased by at least a factor of 5× relative to conventional acquisition, permitting imaging of beam sensitive materials to be obtained without changing the microscope operating parameters. The use of sparse line-hopping scan to acquire STEM images is demonstrated with atomic resolution aberration corrected the Z-contrast images of CaCO3, a material that is traditionally difficult to image by TEM/STEM because of dosage issues.
Universal threshold for femtosecond laser ablation with oblique illumination
Authors: Liu Xiao-Long , Cheng Weibo , Petrarca Massimo , Polynkin Pavel
Published: October 2016

We quantify the dependence of the single-shot ablation threshold on the angle of incidence and polarization of a femtosecond laser beam, for three dissimilar solid-state materials: a metal, a dielectric, and a semiconductor. Using the constant, linear value of the index of refraction, we calculate the laser fluence transmitted through the air-material interface at the point of ablation threshold. We show that, in spite of the highly nonlinear ionization dynamics involved in the ablation process, the so defined transmitted threshold fluence is universally independent of the angle of incidence and polarization of the laser beam for all three material types. We suggest that angular dependence of ablation threshold can be utilized for profiling fluence distributions in ultra-intense femtosecond laser beams.
Trapping and manipulation of individual nanoparticles in a planar Paul trap
Authors: Alda I. , Berthelot J. , Rica R. A. , Quidant R.
Published: October 2016

Visualisation and manipulation of nanoscale matter is one of the main and current challenges in nanosciences. To this aim, different techniques have been recently developed to non-invasively trap and manipulate nano-specimens, like nanoparticles or molecules. However, operating in air or vacuum still remains very challenging since most approaches are limited to a liquid environment. In this letter, we design and characterise a planar Paul trap optimised to trap and manipulate individual charged nanoparticles. This configuration offers competitive capabilities to manipulate nano-specimens in air or vacuum, including in-plane integration, high trap confinement along with dynamical trap reconfiguration, pointing towards applications in the field of levitated optomechanics.
Influence of the temporal variations of plasma composition on the cyclic formation of dust in hexamethyldisiloxane-argon radiofrequency discharges: Analysis by time-resolved mass spectrometry
Authors: Despax B. , Gaboriau F. , Caquineau H. , Makasheva K.
Published: October 2016

Cyclic formation of dust nanoparticles in hexamethyldisiloxane (HMDSO, Si2O(CH3)6)-argon RF discharge with pulsed injection of HMDSO was studied using time-resolved mass spectrometry (MS) and optical emission spectroscopy (OES). A large amount of C2H2, considered as promoter of dust nucleation in hydrocarbon plasmas, was found as a by-product of HMDSO fragmentation. Although no negative ions were detected the presence of C2H2 in the HMDSO-Ar discharge supports the hypothesis of a dust growth mechanism based on negative ions being trapped in the plasma. It was found that at the beginning of each cycle of dust formation during α–γ′ transition, the discharge sustaining process is accompanied by a strong consumption of the HMDSO main by-products: HMDSO-15, CH4 and C2H2. At the end of the cycle, corresponding to the progressive disappearance of dust, the discharge switches back to its initial conditions. The beginning of the inverse transition, i.e. γ′–α, is most likely correlated to the growing void in the dust cloud and dust disappearance. In presence of dust nanoparticles, Ar+ and ArH+ dominate the ion population and consequently the discharge maintenance. When the dust particles gradually disappear, the discharge is rather controlled by Si2O(CH3)5+ ions. Moreover, the increased amount of such heavy ions reveals clearly their important income in the dust repelling process due to the drag force on the large sized dust even at short time scale during the injection time of HMDSO. Atomic-H production increases during the transition from dusty plasma to HMDSO-rich plasma with no dust and its role is associated to a delay in the dust nucleation stage.
Changes in the distribution of reports of the koala (Phascolarctos cinereus) after 16 years of local conservation initiatives at Gunnedah, north-west New South Wales, Australia
Authors: Ellis Murray V. , Rhind Susan G. , Smith Martin , Lunney Daniel
Published: October 2016

In the early 1990s the koala became the mascot for a revegetation program to control salinity on agricultural land around Gunnedah in New South Wales, and a snapshot of the koala’s distribution in the shire was collected at that time, mainly via a mail survey. After the success of tree plantings in the 1990s, the koala population of the Liverpool Plains became a focus of increasing local conservation efforts, as well as research to explain koala population dynamics. This included a repeat mail survey conducted in 2006, which enabled the comparison of the reported distributions to be undertaken. These two citizen science surveys had different response rates but both produced extensive datasets. By 2006, koalas were reported from a wider extent than in 1990, particularly to the north and east of the town, and in more developed agricultural areas, but with highest densities in areas with more than 25% wooded vegetation. In 1990, koalas were reported mostly from locations that were surrounded by more than 40% wooded vegetation with the core of the distribution being on the basalt hills south of the town of Gunnedah. Koalas were also reported with increased relative frequency in the town, and this formed the core of the reported sightings at that time. There were still no reports from many of the vegetated hilly margins of the shire. The observed changes in the pattern of reporting reflects the actual distribution of koalas intersected with the likelihood of observation and the willingness of people to report koalas, and also identify the areas that may be under-sampled to determine the true habitat breath of koalas in the area.
Diversity components and assembly patterns of plant functional traits determine community spatial stability under resource gradients in a desert steppe
Authors: Na Zhao , Zhengwen Wang , Xinqing Shao , Kun Wang
Published: October 2016

The diversity–stability relationship has been addressed and debated for decades, but how this relationship is affected by nutrient availability remains contentious. In the present study we assessed the effects of plant diversity, in terms of species richness, functional group composition and functional trait diversity, on the spatial stability of net primary productivity (NPP) following nitrogen and phosphorus application. In addition, we explored how functional traits at the species level contribute to the spatial stability of NPP. The results support the hypothesis that greater diversity leads to higher spatial stability. This relationship was highly dependent on soil nutrient availability, and increasing species richness or functional trait diversity significantly increased spatial variation of NPP under a high N fertilisation level. The effects of high mineral fertilisation rates may perhaps have masked the effects of plant diversity. Although species richness or functional trait diversity of the original and modified communities from which species with particular functional traits had been removed were significantly different, there were no differences in the coefficients of variation in the NPP of those communities. The lack of difference demonstrated that the relationship between spatial variability and biodiversity depended on the measure of diversity applied and that the functional group composition exerted a stronger effect than other diversity measures. Further analyses revealed that spatial stability of NPP was enhanced with increased diversity in vegetative plant height, rooting depth and the presence of legume, and diminished with diversity in the root system type and life cycle under some fertilisation treatments. The present study demonstrates that the relationship between biodiversity and ecosystem functioning is variable with different diversity, identity and environmental factors. Evaluating the contribution of particular traits to community stability will ultimately help us better understand the mechanisms underlying the diversity–stability relationship.
PDE1C deficiency antagonizes pathological cardiac remodeling and dysfunction
Authors: Knight Walter E. , Chen Si , Zhang Yishuai , Oikawa Masayoshi , Wu Meiping , Zhou Qian , Miller Clint L. , Cai Yujun , Mickelsen Deanne M. , Moravec Christine , Small Eric M. , Abe Junichi , Yan Chen
Published: October 2016

Significance

Heart failure is the leading global cause of death; therefore developing a greater understanding of disease etiology and identifying novel therapeutic targets is critical. Here, we describe the role of the cyclic nucleotide-degrading protein phosphodiesterase 1C (PDE1C) in the context of pathological cardiac remodeling. In cardiac myocytes, we found that PDE1C regulates both cyclic AMP- and cyclic GMP-mediated signaling pathways under different conditions. In both isolated cells and mice we found that inhibition of PDE1C could potentiate protective signaling and prevent the development of many aspects of heart failure, potentially by signaling through multiple cell types. PDE1 inhibition therefore may represent a viable therapeutic strategy for treatment of heart failure.
Exceptionalist naturalism: Human agency and the causal order
Authors: Turri John
Published: October 2016

This paper addresses a fundamental question in folk metaphysics: How do we ordinarily view human agency? According to the transcendence account, we view human agency as standing outside of the causal order and imbued with exceptional powers. According to a naturalistic account, we view human agency as subject to the same physical laws as other objects and completely open to scientific investigation. According to exceptionalist naturalism, the truth lies somewhere in between: We view human agency as fitting broadly within the causal order while still being exceptional in important respects. In this paper, I report seven experiments designed to decide between these three competing theories. Across a variety of contexts and types of action, participants agreed that human agents can resist outcomes described as inevitable, guaranteed, and causally determined. Participants viewed non-human animal agents similarly, whereas they viewed computers, robots, and simple inanimate objects differently. At the same time, participants judged that human actions are caused by many things, including psychological, neurological, and social events. Overall, in folk metaphysics, human and non-human animals are viewed as exceptional parts of the natural world.
Optimizing ChIP-seq peak detectors using visual labels and supervised machine learning
Authors: Hocking Toby Dylan , Goerner-Potvin Patricia , Morin Andreanne , Shao Xiaojian , Pastinen Tomi , Bourque Guillaume
Published: October 2016

Motivation

Many peak detection algorithms have been proposed for ChIP-seq data analysis, but it is not obvious which algorithm and what parameters are optimal for any given dataset. In contrast, regions with and without obvious peaks can be easily labeled by visual inspection of aligned read counts in a genome browser. We propose a supervised machine learning approach for ChIP-seq data analysis, using labels that encode qualitative judgments about which genomic regions contain or do not contain peaks. The main idea is to manually label a small subset of the genome, and then learn a model that makes consistent peak predictions on the rest of the genome.

Results

We created 7 new histone mark datasets with 12 826 visually determined labels, and analyzed 3 existing transcription factor datasets. We observed that default peak detection parameters yield high false positive rates, which can be reduced by learning parameters using a relatively small training set of labeled data from the same experiment type. We also observed that labels from different people are highly consistent. Overall, these data indicate that our supervised labeling method is useful for quantitatively training and testing peak detection algorithms.

Availability and Implementation

Labeled histone mark data http://cbio.ensmp.fr/~thocking/chip-seq-chunk-db/, R package to compute the label error of predicted peaks https://github.com/tdhock/PeakError

Supplementary information

Supplementary data are available at Bioinformatics online.
Judicial Intervention and Industrial Relations: Exploring Industrial Disputes Cases in West Bengal
Authors: Banerjee Supurna , Mahmood Zaad
Published: October 2016

This paper examines a relatively neglected dimension of industrial relation in India, namely judicial intervention in industrial disputes. Through an interrogation of judicial intervention in capital-labour disputes in the state of West Bengal, the paper makes an original contribution to the literature. Through quantitative as well as qualitative examination of court cases, the paper addresses some important questions concerning the nature of judicial intervention. Does the declining force of trade union movements signify a corresponding shift to judicial recourse or an increasing pro-labour judiciary? How are the disputes read by the judiciary: do they adhere to a strict legalistic understanding or does their intervention involve going beyond the letter of the law? Is there uniformity in the nature of verdicts along the spectrum of the judiciary, ie, from the labour tribunals to the higher judiciary (High Court/Supreme Court)? Through an extensive case study of court judgments from labour tribunal to High Court to Supreme Court (where applicable), the paper situates the answers to these questions in the unique context of the sub-state of West Bengal with its specific political framework. Investigating the disjuncture between the legal prescriptions and their invisible implications, or between the jurisprudence at different levels, the paper provides clues to understanding not only the way judicial intervention plays out but also the way in which industrial relations are managed and understood in the context of West Bengal.
Suzaku observations of spectral variations of the ultra-luminous X-ray source Holmberg IX X-1
Authors: Kobayashi Shogo B. , Nakazawa Kazuhiro , Makishima Kazuo
Published: October 2016

Observations of the ultra-luminous X-ray source (ULX) Holmberg IX X-1 were carried out with Suzaku twice, once on 2012 April 13 and then on 2012 October 24, with exposures of 180 ks and 217 ks, respectively. The source showed a hard power-law shaped spectrum with a mild cutoff at ∼8 keV, which is typical of ULXs when they are relatively dim. On both occasions, the 0.6–11 keV spectrum was explained successfully in terms of a cool (∼0.2 keV) multi-color disk blackbody emission model and thermal Comptonization emission produced by an electron cloud with a relatively low temperature and high optical depth, assuming that a large fraction of the disk-blackbody photons are Comptonized whereas the rest are observed directly. The 0.5–10 keV luminosity was 1.2 × 1040 erg s−1 in April, and ∼14% higher in October. This brightening was accompanied by spectral softening in ≥2 keV, with little change in the ≤2 keV spectral shape. This behavior can be understood if the accretion disk remains unchanged while the electron cloud covers a variable fraction of the disk. The absorbing column density was consistent with the galactic line-of sight value, and did not vary by more than 1.6 × 1021 cm−2. Together with the featureless spectra, these properties may not be reconciled easily with the super-critical accretion scenario of this source.
Conformational flexibility of an anti-IL-13 DARPin†
Authors: Teplyakov Alexey , Malia Thomas J. , Obmolova Galina , Jacobs Steven A. , O'Neil Karyn T. , Gilliland Gary L.
Published: October 2016

Designed ankyrin repeat proteins (DARPin®) are artificial non-immunoglobulin binding proteins with potential applications as therapeutic molecules. DARPin 6G9 binds interleukin-13 with high affinity and blocks the signaling pathway and as such is promising for the treatment of asthma and other atopic diseases. The crystal structures of DARPin 6G9 in the unbound form and in complex with IL-13 were determined at high resolution. The DARPin competes for the same epitope as the IL-13 receptor chain 13Rα1 but does not interfere with the binding of the other receptor chain, IL-4Rα. Analysis of multiple copies of the DARPin molecule in the crystal indicates the conformational instability in the N-terminal cap that was predicted from molecular dynamics simulations. Comparison of the DARPin structures in the free state and in complex with IL-13 reveals a concerted movement of the ankyrin repeats upon binding resulted in the opening of the binding site. The induced-fit mode of binding employed by DARPin 6G9 is very unusual for DARPins since they were designed as particularly stable and rigid molecules. This finding shows that DARPins can operate by various binding mechanisms and suggests that some flexibility in the scaffold may be an advantage.