bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental and numerical investigations of air plasmas induced by multi-MeV pulsed X-ray from low to atmospheric pressures
Authors: Maulois Mélissa , Ribière Maxime , Eichwald Olivier , Yousfi Mohammed , Pouzalgues Romain , Garrigues Alain , Delbos Christophe , Azaïs Bruno
Published: September 2016

This research work is devoted to the experimental and theoretical analysis of air plasmas induced by multi-MeV pulsed X-ray for a large pressure range of humid air background gas varying from 20 mbar to atmospheric pressure. The time evolution of the electron density of the air plasma is determined by electromagnetic wave absorption measurements. The measurements have uncertainties of about ±30%, taking into account the precision of the dose measurement and also the shot to shot fluctuations of the generator. The experimental electron density is obtained by comparing the measurements of the transmitted microwave signals to the calculated ones. The calculations need the knowledge of the time evolution of the electron mean energy, which is determined by a chemical kinetic model based on a reaction scheme involving 39 species interacting following 265 reactions. During the X-ray pulse, a good agreement is obtained between time evolution of the electron density obtained from absorption measurements and calculations based on the kinetic model. The relative deviation on the maximum electron density and the corresponding plasma frequency is always lower than 10%. The maximum electron density varies from 4 × 1011 to 3.5 × 1013 cm−3 between 30 mbar to atmospheric pressure, while the peak of the electron mean energy decreases from 5.64 eV to 4.27 eV in the same pressure range.
Defect assisted saturable absorption characteristics in Al and Li doped ZnO thin films
Authors: K. M. Sandeep , Bhat Shreesha , S. M. Dharmaprakash , P. S. Patil , K. Byrappa
Published: September 2016

The influence of different doping ratios of Al and Li on the nonlinear optical properties, namely, a two-photon absorption and a nonlinear refraction using single beam Z-scan technique, of nano-crystalline ZnO thin films has been investigated in the present study. A sol-gel spin-coated pure ZnO, Al-doped ZnO (AZO), and Li-doped ZnO (LZO) thin films have been prepared. The stoichiometric deviations induced by the occupancy of Al3+ and Li+ ions at the interstitial sites injects the compressive stress in the AZO and LZO thin films, respectively, while the extended defect states below the conduction band leads to a redshift of energy band gap in the corresponding films as compared to pure ZnO thin film. Switching from an induced absorption in ZnO and 1 at. wt. % doped AZO and LZO films to a saturable absorption (SA) in 2 at. wt. % doped AZO and LZO films has been observed, and it is attributed to the saturation of a linear absorption of the defect states. The closed aperture Z-scan technique revealed the self-focusing (a positive nonlinear refractive index) in all the films, which emerge out of the thermo-optical effects due to the continuous illumination of laser pulses. A higher third-order nonlinear optical susceptibility χ(3) of the order 10−3 esu has been observed in all the films.
Stress-determined nucleation sites above GaAs-capped arrays of InAs quantum dots
Authors: Latini V. , Placidi E. , Arciprete F. , Tisbi E. , Patella F. , Magri R.
Published: September 2016

We studied the stress field at the surface of GaAs capping layers of variable thicknesses burying InAs quantum dot arrays using the Finite Element method to solve numerically the equations of the elastic field. The aim is to determine the stress-determined favorable sites for dot nucleation. We show that: (i) depending on the cap thickness, dot distances, and array orientation, sudden transitions in the stress-strain fields occur, leading from a vertical alignment of the dots to an anti-aligned correlation. We find that just few determined positions are favorable for dot nucleation and exclude some other sites previously indicated as favorable in the literature; (ii) the critical thicknesses at which the switch between the vertical alignment and the anti-aligned positions occurs depend on the distance between the dots in a square array and on the ratio between the two different distances if the arrays are rectangular; (iii) the transitions occur within a few nanometer range of the capping layer thickness, and the elastic field undergoes large changes in its properties before and after the transition. This behavior has been revealed by a very accurate fit of the tangential stress field using appropriate fit functions. The fit and parameter functions allow to easily reproduce the stress field in different contexts and are useful in growth simulation models. The results suggest that by properly engineering the capping layer thicknesses in the layers of a stack, it is possible to obtain different three-dimensional quantum dot lattices starting from an initial fixed dot array. Our results are in agreement with the available experimental data.
Formation of Ni3InGaAs phase in Ni/InGaAs contact at low temperature
Authors: Perrin C. , Ghegin E. , Zhiou S. , Nemouchi F. , Rodriguez P. , Gergaud P. , Maugis P. , Mangelinck D. , Hoummada K.
Published: September 2016

The composition and morphology of the product phase after the reaction of Ni thin film with In0.53Ga0.47As substrate at 350 °C were investigated by atom probe tomography, X-ray diffraction, and scanning electron microscopy. Results show the formation of a unique Ni3(In0.53Ga0.47)As phase with a low concentration in-depth gradient of Ni and the decoration of the grain boundaries by In atoms. These analyses indicate that Ni is the main diffusing specie during the growth of Ni3(In0.53Ga0.47)As phase. The volume of the product phase is higher than the volume of the consumed Ni film as expected for the formation of Ni3(In0.53Ga0.47)As phase.
High speed X-ray phase contrast imaging of energetic composites under dynamic compression
Authors: Parab Niranjan D. , Roberts Zane A. , Harr Michael H. , Mares Jesus O. , Casey Alex D. , Gunduz I. Emre , Hudspeth Matthew , Claus Benjamin , Sun Tao , Fezzaa Kamel , Son Steven F. , Chen Weinong W.
Published: September 2016

Fracture of crystals and frictional heating are associated with the formation of “hot spots” (localized heating) in energetic composites such as polymer bonded explosives (PBXs). Traditional high speed optical imaging methods cannot be used to study the dynamic sub-surface deformation and the fracture behavior of such materials due to their opaque nature. In this study, high speed synchrotron X-ray experiments are conducted to visualize the in situ deformation and the fracture mechanisms in PBXs composed of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) crystals and hydroxyl-terminated polybutadiene binder doped with iron (III) oxide. A modified Kolsky bar apparatus was used to apply controlled dynamic compression on the PBX specimens, and a high speed synchrotron X-ray phase contrast imaging (PCI) setup was used to record the in situ deformation and failure in the specimens. The experiments show that synchrotron X-ray PCI provides a sufficient contrast between the HMX crystals and the doped binder, even at ultrafast recording rates. Under dynamic compression, most of the cracking in the crystals was observed to be due to the tensile stress generated by the diametral compression applied from the contacts between the crystals. Tensile stress driven cracking was also observed for some of the crystals due to the transverse deformation of the binder and superior bonding between the crystal and the binder. The obtained results are vital to develop improved understanding and to validate the macroscopic and mesoscopic numerical models for energetic composites so that eventually hot spot formation can be predicted.
Scale-invariant gauge theories of gravity: Theoretical foundations
Authors: Lasenby A. N. , Hobson M. P.
Published: September 2016

We consider the construction of gauge theories of gravity, focussing in particular on the extension of local Poincaré invariance to include invariance under local changes of scale. We work exclusively in terms of finite transformations, which allow for a more transparent interpretation of such theories in terms of gauge fields in Minkowski spacetime. Our approach therefore differs from the usual geometrical description of locally scale-invariant Poincaré gauge theory (PGT) and Weyl gauge theory (WGT) in terms of Riemann–Cartan and Weyl–Cartan spacetimes, respectively. In particular, we reconsider the interpretation of the Einstein gauge and also the equations of motion of matter fields and test particles in these theories. Inspired by the observation that the PGT and WGT matter actions for the Dirac field and electromagnetic field have more general invariance properties than those imposed by construction, we go on to present a novel alternative to WGT by considering an “extended” form for the transformation law of the rotational gauge field under local dilations, which includes its “normal” transformation law in WGT as a special case. The resulting “extended” Weyl gauge theory (eWGT) has a number of interesting features that we describe in detail. In particular, we present a new scale-invariant gauge theory of gravity that accommodates ordinary matter and is defined by the most general parity-invariant eWGT Lagrangian that is at most quadratic in the eWGT field strengths, and we derive its field equations. We also consider the construction of PGTs that are invariant under local dilations assuming either the “normal” or “extended” transformation law for the rotational gauge field, but show that they are special cases of WGT and eWGT, respectively.
Kernels and point processes associated with Whittaker functions
Authors: Blower Gordon , Chen Yang
Published: September 2016

This article considers Whittaker’s confluent hypergeometric function Wκ,μ where κ is real and μ is real or purely imaginary. Then φ(x) = x−μ−1/2Wκ,μ(x) arises as the scattering function of a continuous time linear system with state space L2(1/2, ∞) and input and output spaces C. The Hankel operator Γφ on L2(0, ∞) is expressed as a matrix with respect to the Laguerre basis and gives the Hankel matrix of moments of a Jacobi weight w0(x) = xb(1 − x)a. The operation of translating φ is equivalent to deforming w0 to give wt(x) = e−t/xxb(1 − x)a. The determinant of the Hankel matrix of moments of wε satisfies the σ form of Painlevé’s transcendental differential equation PV. It is shown that Γφ gives rise to the Whittaker kernel from random matrix theory, as studied by Borodin and Olshanski [Commun. Math. Phys. 211, 335–358 (2000)]. Whittaker kernels are closely related to systems of orthogonal polynomials for a Pollaczek–Jacobi type weight lying outside the usual Szegö class.
Strong averaging principle for two-time-scale non-autonomous stochastic FitzHugh-Nagumo system with jumps
Authors: Xu Jie , Miao Yu , Liu Jicheng
Published: September 2016

In this paper, we study an averaging principle for stochastic FitzHugh-Nagumo system with different time scales driven by cylindrical Wiener processes and Poisson jumps, where the slow equation is non-autonomous and the fast equation is autonomous case. Under suitable assumptions, we show that the slow component mean-square strongly converges to the solution of the corresponding averaging equation, and the rate of the convergence as a by-product is also affirmed. Finally, we give some open problems which are derived from this paper.
Infrared Stark and Zeeman spectroscopy of OH–CO: The entrance channel complex along the OH + CO → trans-HOCO reaction pathway
Authors: Brice Joseph T. , Liang Tao , Raston Paul L. , McCoy Anne B. , Douberly Gary E.
Published: September 2016

Sequential capture of OH and CO by superfluid helium droplets leads exclusively to the formation of the linear, entrance-channel complex, OH–CO. This species is characterized by infrared laser Stark and Zeeman spectroscopy via measurements of the fundamental OH stretching vibration. Experimental dipole moments are in disagreement with ab initio calculations at the equilibrium geometry, indicating large-amplitude motion on the ground state potential energy surface. Vibrational averaging along the hydroxyl bending coordinate recovers 80% of the observed deviation from the equilibrium dipole moment. Inhomogeneous line broadening in the zero-field spectrum is modeled with an effective Hamiltonian approach that aims to account for the anisotropic molecule-helium interaction potential that arises as the OH–CO complex is displaced from the center of the droplet.
Electromagnetic analysis of the HPM oscillator—Reltron
Authors: Mahto Manpuran , Jain P. K.
Published: September 2016

In this paper, electromagnetic analysis of the reltron, which is a compact, simple, and efficient high power microwave source has been presented. The beam wave interaction process of the reltron oscillator has been analyzed to understand the device physics. The split cavity oscillator and relativistic klystron principles have been extended to demonstrate the electric field responsible for beam bunching and the electron beam modulation process in the reltron. The analytical formulation to obtain the RF energy growth and efficiency of the device has also been presented. To validate the analytical results and to evaluate the overall performance of the device, beam present simulation of reltron has been performed using commercial 3D PIC simulation code “CST Particle Studio.” With the parameters of a previously reported experimental reltron device, the present analytical calculation provided ∼240 MW RF output power with ∼38% efficiency while the PIC simulation provided RF output power of ∼225 MW with ∼36% efficiency at 2.75 GHz frequency. The obtained analytical and simulation results have also been found to be in agreement of ∼6% with this experimental work.
Direct observation of UV-induced charge accumulation in inverted-type polymer solar cells with a TiOx layer: Microscopic elucidation of the light-soaking phenomenon
Authors: Son D. , Kuwabara T. , Takahashi K. , Marumoto K.
Published: September 2016

The mechanism of light-soaking phenomenon in inverted-type organic solar cells (IOSCs) with a structure of indium-tin-oxide/TiOx/P3HT:PCBM/Au was studied by electron spin resonance (ESR) spectroscopy. Charge accumulation in the cell during UV-light irradiation was observed using ESR, which was clearly correlated with the light-soaking phenomenon. The origin of the charge accumulation is clarified as holes that are deeply trapped at p-type P3HT polymer-chain ends with bromine after hole transfer from the band excitation in the TiOx layer. The holes are considered to be electrostatically attracted to trapped electrons in the TiOx layer after the band excitation. These accumulated charges are the origin of the light-soaking phenomenon. Our results strongly suggest that passivation of the residual OH groups in the TiOx layer is needed to avoid the light-soaking phenomenon by preventing electron trappings, a step that is indispensable in the operation of highly stable IOSCs without UV-light irradiation based on a low-cost and low-temperature device fabrication process using flexible plastic substrates.
Broadband fractal acoustic metamaterials for low-frequency sound attenuation
Authors: Song Gang Yong , Cheng Qiang , Huang Bei , Dong Hui Yuan , Cui Tie Jun
Published: September 2016

We fabricate and experimentally characterize a broadband fractal acoustic metamaterial that can serve to attenuate the low-frequency sounds at selective frequencies ranging from 225 to 1175 Hz. The proposed metamaterials are constructed by the periodic Hilbert fractal elements made of photosensitive resin via 3D printing. In analogy to electromagnetic fractal structures, it is shown that multiple resonances can also be excited in the acoustic counterpart due to their self-similar properties, which help to attenuate the acoustic energy in a wide spectrum. The confinement of sound waves in such subwavelength element is evidenced by both numerical and experimental results. The proposed metamaterial may provide possible alternative for various applications such as the noise attenuation and the anechoic materials.
Electrical and optical conductivities of hole gas in p-doped bulk III–V semiconductors
Authors: Mawrie Alestin , Halder Pushpajit , Ghosh Barun , Ghosh Tarun Kanti
Published: September 2016

We study electrical and optical conductivities of hole gas in p-doped bulk III-V semiconductors described by the Luttinger Hamiltonian. We provide exact analytical expressions of the Drude conductivity, inverse relaxation time for various impurity potentials, Drude weight, and optical conductivity in terms of the Luttinger parameters γ1 and γ2. The back scattering is completely suppressed as a result of the helicity conservation of the heavy and light hole states. The energy dependence of the relaxation time for the hole states is different from the Brooks-Herring formula for electron gas in n-doped semiconductors. We find that the inverse relaxation time of heavy holes is much less than that of the light holes for Coulomb-type and Gaussian-type impurity potentials and vice-versa for a short-range impurity potential. The Drude conductivity increases non-linearly with the increase in the hole density. The exponent of the density dependence of the conductivity is obtained in the Thomas-Fermi limit. The Drude weight varies linearly with the density even in the presence of the spin-orbit coupling. The finite-frequency optical conductivity goes as ω, and its amplitude strongly depends on the Luttinger parameters. The Luttinger parameters can be extracted from the optical conductivity measurement.
Near-field imaging of single walled carbon nanotubes emitting in the telecom wavelength range
Authors: La China F. , Caselli N. , Sarti F. , Biccari F. , Torrini U. , Intonti F. , Vinattieri A. , Durán-Valdeiglesias E. , Alonso Ramos C. , Le Roux X. , Balestrieri M. , Filoramo A. , Vivien L. , Gurioli M.
Published: September 2016

Hybrid systems based on carbon nanotubes emitting in the telecom wavelength range and Si-photonic platforms are promising candidates for developing integrated photonic circuits. Here, we consider semiconducting single walled carbon nanotubes (s-SWNTs) emitting around 1300 nm or 1550 nm wavelength. The nanotubes are deposited on quartz substrate for mapping their photoluminescence in hyperspectral near-field microscopy. This method allows for a sub-wavelength resolution in detecting the spatial distribution of the emission of single s-SWNTs at room temperature. Optical signature delocalized over several micrometers is observed, thus denoting the high quality of the produced carbon nanotubes on a wide range of tube diameters. Noteworthy, the presence of both nanotube bundles and distinct s-SWNT chiralities is uncovered.
Interactions of electrons with two lower hybrid waves
Authors: Huang Yueheng , Xiang Nong , Jia Guozhang , Li Dehui , Wang Xueyi , Lin Yu
Published: September 2016

The effects of perturbed orbits on the interactions of electrons with two lower hybrid waves, one of which is resonant with electrons at a low phase velocity (vp1 = 3.8Vthe, where vp1 is the wave phase velocity and Vthe is the electron thermal speed) while the other is off-resonant at a high phase velocity (vp2 = 5.5Vthe), have been studied by using the particle simulation code based on the gyro-kinetic electron and fully-kinetic ion (GeFi) model [Lin et al., Plasma Phys. Controlled Fusion 47, 657 (2005)]. When the amplitude of the off-resonant wave is sufficiently small so that the resonances of these two waves do not overlap, the variation of the resonant wave amplitude is similar to that predicted by O'Neil's theory [O'Neil, Plasma Fluid 8, 12 (1965)]. With the increasing amplitude, the two resonances overlap and large scale chaos emerges. As a result, the damping of the resonant wave can be enhanced, which is due to that the trapped electron orbits are significantly perturbed by the off-resonant wave. The diffusion process gives rise to the enhanced damping. When the overlap is sufficiently large, the damping of the off-resonant wave and the oscillatory behavior of the wave amplitude are observed. In addition, the resonant plateau in the distribution function can be broadened due to the change in the chaotic region boundaries as the electron perturbed orbits are taken into account.
An automated system for high-throughput generation and optimization of microdroplets
Authors: Wang Zongjie , Samanipour Roya , Gamaleldin Mohamed , Sakthivel Kabilan , Kim Keekyoung
Published: September 2016

Microdroplets have been widely used in various biomedical applications. During droplet generation, parameters are manually adjusted to achieve the desired size of droplets. This process is tedious and time-consuming. In this paper, we present a fully automated system for controlling the size of droplets to optimize droplet generation parameters in a microfluidic flow-focusing device. The developed system employed a novel image processing program to measure the diameter of droplets from recorded video clips and correspondingly adjust the flow rates of syringe pumps to obtain the required diameter of droplets. The system was tested to generate phosphate-buffered saline and 8% polyethylene (glycol) diacrylate prepolymer droplets and regulate its diameters at various flow rates. Experimental results demonstrated that the difference between droplet diameters from the image processing and manual measurement is not statistically significant and the results are consistent over five repetitions. Taking the advantages of the accurate image processing method, the size of the droplets can be optimized in a precise and robust manner via automatically adjusting flow rates by the feedback control. The system was used to acquire quantitative data to examine the effects of viscosity and flow rates. Droplet-based experiments can be greatly facilitated by the automatic droplet generation and optimization system. Moreover, the system is able to provide quantitative data for the modelling and application of droplets with various conditions in a high-throughput way.
Experimental demonstration of a band-notched line-defect waveguide in a surface-wave photonic crystal
Authors: Gao Zhen , Gao Fei , Xu Hongyi , Zhang Youming , Zhang Baile
Published: September 2016

We propose and experimentally demonstrate a band-notched line-defect waveguide in a surface-wave photonic crystal, which consists of a straight line-defect waveguide and side-coupled defect cavities. A narrow stop band can be observed in the broadband transmission spectra. We also demonstrate that both the filtering levels and filtering frequencies of the band-notched line-defect waveguide can be adjusted through changing the number and the height of metallic pillars of the side-coupled defect cavities. The band-notch function is based on the idea that the propagating surface modes with the resonance frequencies of the side-coupled defect cavities will be tightly localized around the defect sites, being filtered from the waveguide output. Transmission spectra measurements and direct near-field profile imaging are performed at microwave frequencies to verify our design. These results may enable various band-notched devices applications and provide routes for the realization of surface-wave filters on a single metal surface.
Determination of the mechanism and extent of surface degradation in Ni-based cathode materials after repeated electrochemical cycling
Authors: Hwang Sooyeon , Kim Se Young , Chung Kyung Yoon , Stach Eric A. , Kim Seung Min , Chang Wonyoung
Published: September 2016

We take advantage of scanning transmission electron microscopy and electron energy loss spectroscopy to investigate the changes in near-surface electronic structure and quantify the degree of local degradation of Ni-based cathode materials with the layered structure (LiNi0.8Mn0.1Co0.1O2 and LiNi0.4Mn0.3Co0.3O2) after 20 cycles of delithiation and lithiation. Reduction of transition metals occurs in the near-surface region of cathode materials: Mn is the major element to be reduced in the case of relatively Mn-rich composition, while reduction of Ni ions is dominant in Ni-rich materials. The valences of Ni and Mn ions are complementary, i.e., when one is reduced, the other is oxidized in order to maintain charge neutrality. The depth of degradation zone is found to be much deeper in Ni-rich materials. This comparative analysis provides important insights needed for the devising of new cathode materials with high capacity as well as long lifetime.
Effect of annealing on the interfacial Dzyaloshinskii-Moriya interaction in Ta/CoFeB/MgO trilayers
Authors: Khan R. A. , Shepley P. M. , Hrabec A. , Wells A. W. J. , Ocker B. , Marrows C. H. , Moore T. A.
Published: September 2016

The interfacial Dzyaloshinskii-Moriya interaction (DMI) has been shown to stabilize homochiral Néel-type domain walls in thin films with perpendicular magnetic anisotropy, and as a result, permit them to be propagated by a spin Hall torque. In this study, we demonstrate that in Ta/Co20Fe60B20/MgO, the DMI may be influenced by annealing. We find that the DMI peaks at D=0.057±0.003 mJ/m2 at an annealing temperature of 230 °C. DMI fields were measured using a purely field-driven creep regime domain expansion technique. The DMI field and the anisotropy field follow a similar trend as a function of annealing temperature. We infer that the behavior of the DMI and the anisotropy are related to interfacial crystal ordering and B expulsion out of the CoFeB layer as the annealing temperature is increased.
The diet of the coffin ray, Hypnos monopterygius (Shaw, 1795), and predation mode inferred from jaw, dentition and electric organ morphology
Authors: Frost A.-M. , Jacobsen I. P. , Bennett M. B.
Published: September 2016

The diet of the coffin ray, Hypnos monopterygius (Family Hypnidae), an electric ray endemic to Australia, was described on the basis of stomach contents analysis. Benthos-associated teleost fishes and cephalopod molluscs, predominantly Octopus, dominated the diet. The large, paired electric organs of this species scaled close to isometrically in relation to body mass for electric-organ area and electric-organ mass. The number of electrocyte columns that comprise each electric organ (mean=435 columns) was independent of body mass. Jaws were long and slender, and supported small tricuspidate teeth only on the central 55% of their length. Diet, electric-organ size and jaw morphology in Hypnos and the torpedoes (Family Torpedinidae) are similar, but in marked contrast to members of the numbfishes (Family Narcinidae). The differences are interpreted in relation to the use of electric-organ discharge while foraging in the former families.
Available carbon and nitrate increase greenhouse gas emissions from soils affected by salinity
Authors: Dang Duy Minh , Macdonald Ben , Warneke Sören , White Ian
Published: September 2016

Sea-level rise and saline water intrusion have caused a shortage of fresh water and affected agricultural areas globally. Besides inundation, the salinity could alter soil nitrogen and carbon cycling in coastal soils. To examine the effect of salinity, an incubation experiment was used to investigate soil nitrogen and carbon cycling from an acid sulfate soil and an alluvial soil with and without additional nitrogen and carbon sources. Four levels of saline solution of 0.03, 10, 16 and 21dSm–1 were used to submerge acid sulfate and alluvial soil samples in a 125-mL jar. The experimental jars were incubated in the dark at 25°C. Gas samples were collected over 4 weeks and analysed for nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4). The results showed that salinity significantly decreased N2O emissions from the acid sulfate soil but did not affect emissions from the alluvial soil. Addition of glucose and nitrate enhanced N2O production in both salt-affected soils. Emissions of CO2 were not different among the salinity treatments, whereas available carbon and nitrate promoted soil respiration. Changes in CH4 fluxes over the 4-week incubation were the same for both soils, and substrate addition did not affect emissions in either soil. The findings indicate that salinity has altered carbon and nitrogen cycles in the acid sulfate soil, and future fertiliser and crop management will need to account for the changed nutrient cycling caused by saline water intrusion and climate change.
Nesting ecology of hawksbill turtles at a rookery of international significance in Australia’s Northern Territory
Authors: Hoenner Xavier , Whiting Scott D. , Enever Gavin , Lambert Keith , Hindell Mark A. , McMahon Clive R.
Published: September 2016

Context
Following centuries of intense human exploitation, the global stocks of hawksbill turtle have decreased precipitously and the species is currently considered Critically Endangered by the IUCN. Australia supports the largest breeding aggregations worldwide; however, there are no accurate estimates of population abundance and seasonality for hawksbill turtles at important nesting grounds in eastern Arnhem Land.

Aims
This study was designed to fill in this lack of ecological information and assist with the conservation and management of hawksbill turtles. More specifically, our overarching goals were to assess nesting seasonality, habitat preferences and provide the first estimate of annual nesting population size at a Northern Territory rookery.

Methods
In 2009 and 2010 we collected beach monitoring, satellite telemetry and sand temperature data over two nesting seasons at a group of three islands located 30 km off Groote Eylandt in the Gulf of Carpentaria, northern Australia. We subsequently analysed these data to unravel hawksbill nesting behaviour and reproductive outputs, and examined the vulnerability of this rookery to climate change.

Key results
Hawksbill turtle nesting seasonality consistently started in mid-May, peaked in mid-August and ended in late November. Annual nesting abundance showed a near 3-fold increase between 2009 and 2010, with an average of 220 and 580 hawksbill females nesting on this island group respectively. Sand temperature at 50 cm reached more than 30°C at all monitored sites during most of the peak of the incubation period.

Conclusions
This remote and untouched group of islands constitutes a major hawksbill turtle rookery both nationally and globally. While anthropogenic impacts and predation are low year round, climate change threatens to skew hatchling sex ratios, eventually leading to an increase in hatchling mortality.

Implications
Additional ground-based surveys are required to refine the accuracy of population estimates presented in this study. Given the paucity of data in the region, we recommend this island group off Groote Eylandt be used as a population-monitoring index site for the eastern Arnhem Land hawksbill turtle breeding aggregation.
Green and blue water demand from large-scale land acquisitions in Africa
Authors: Johansson Emma Li , Fader Marianela , Seaquist Jonathan W. , Nicholas Kimberly A.
Published: September 2016

Significance

Freshwater appropriation can have vast impacts, depending on management and scale of water use. Since 2000, foreign investors have contracted an area the size of the United Kingdom in Africa, leading to increased pressure on water resources. Here we couple site-specific water demand for the crops planted there to the efficiency of different irrigation systems, while relating these estimates to local water availability. This approach enables us to identify “hotspot” areas of freshwater use where crops demand more water from irrigation than can be supplied by soil moisture, where the potential water demands from large-scale land acquisitions pose a risk for increased competition over water resources. Of these land acquisitions, 18% would be hotspots even with the most efficient irrigation system implemented.
Laquinimod arrests experimental autoimmune encephalomyelitis by activating the aryl hydrocarbon receptor
Authors: Kaye Joel , Piryatinsky Victor , Birnberg Tal , Hingaly Tal , Raymond Emanuel , Kashi Rina , Amit-Romach Einat , Caballero Ignacio S. , Towfic Fadi , Ator Mark A. , Rubinstein Efrat , Laifenfeld Daphna , Orbach Aric , Shinar Doron , Marantz Yael , Grossman Iris , Knappertz Volker , Hayden Michael R. , Laufer Ralph
Published: September 2016

Significance

Laquinimod is an oral drug currently being evaluated for the treatment of relapsing, remitting, and primary progressive multiple sclerosis as well as Huntington’s disease. It is thought that laquinimod has a primary effect on the peripheral innate immune system and also acts directly on resident cells within the CNS. However, the exact mechanism of action of laquinimod has not been fully elucidated. We investigated gene expression in laquinimod-treated mice and show induction of genes downstream to activation of the aryl hydrocarbon receptor (AhR). In this paper, we examine the role of the AhR in laquinimod treatment of experimental autoimmune encephalomyelitis and demonstrate that AhR is the molecular target of laquinimod in this model.
Testosterone causes both prosocial and antisocial status-enhancing behaviors in human males
Authors: Dreher Jean-Claude , Dunne Simon , Pazderska Agnieszka , Frodl Thomas , Nolan John J. , O’Doherty John P.
Published: September 2016

Significance

Although in several species of bird and animal, testosterone increases male–male aggression, in human males, it has been suggested to instead promote both aggressive and nonaggressive behaviors that enhance social status. However, causal evidence distinguishing these accounts is lacking. Here, we tested between these hypotheses in men injected with testosterone or placebo in a double-blind, randomized design. Participants played a modified Ultimatum Game, which included the opportunity to punish or reward the other player. Administration of testosterone caused increased punishment of the other player but also, increased reward of larger offers. These findings show that testosterone can cause prosocial behavior in males and provide causal evidence for the social status hypothesis in men.
Statecraft and expansionary dynamics: A Virú outpost at Huaca Prieta, Chicama Valley, Peru
Authors: Millaire Jean-François , Prieto Gabriel , Surette Flannery , Redmond Elsa M. , Spencer Charles S.
Published: September 2016

Significance

Cross-cultural analyses of early statecraft suggest that territorial expansion was an integral part of the process of primary state formation, closely associated with the delegation of authority to subordinate administrators and the construction of core outposts of the state in foreign territories. Understood as instruments of territorial expansion that were closely tied to historical processes, such outposts offer important viewpoints on the evolutionary trajectories of specific early states and also on the nature and extent of the foreign policy of archaic states in general.
The communicative relevance of auditory nuisance
Authors: Pongrácz Péter , Czinege Nikolett , Haynes Thaissa Menezes Pavan , Tokumaru Rosana Suemi , Miklósi Ádám , Faragó Tamás
Published: September 2016

Excessive dog barking is among the leading sources of noise pollution world-wide; however, the reasons for the annoyance of barking to people remained uninvestigated. Our questions were: is the annoyance rating affected by the acoustic parameters of barks; does the attributed inner state of the dog and the nuisance caused by its barks correlate; does the gender and country of origin affect the subjects’ sensitivity to barking. Participants from Hungary (N = 100) and Brazil (N = 60) were tested with sets of 27 artificial bark sequences. Subjects rated each bark according to the inner state of the dog and the annoyance caused by the particular bark. Subjects from both countries found high-pitched barks the most annoying: however, harsh, fast-pulsing, low-pitched barks were also unpleasant. Men found high-pitched barks more annoying than the women did. Annoyance ratings showed positive correlation with assumed negative inner states of the dog, positive emotional ratings showed negative correlation with the annoyance level. This is the first indication that acoustic features that were selected for effective vocal signalling may be annoying for human listeners. Among the explanations for this effect the role of affective communication and similar bioacoustics of particular animal vocalizations and baby cries are discussed.
Voice features of telephone operators predict auditory preferences of consumers
Authors: André Vanessa , Petr Christine , André Nicolas , Hausberger Martine , Lemasson Alban
Published: September 2016

What makes a human voice agreeable is a matter of scientific discussion. Whereas prosody was shown to play a role regarding “male-female” attraction, the impact of frequency modulations in “non-sexual”, notably commercial, contexts has attracted little attention. Another point unaddressed in the literature is auditory sensitivity to short-term frequency modulations as current studies focus more on sentence. Thirty French female operators were recorded over the phone. All “bonjour” greeting words were classified in terms of frequency modulation linearity and orientation at the syllable and word levels. Then, the different voices were played back to students and seniors who had to rate each voice according to their degree of agreeableness. Listeners preferred non-monotonous voices. Differences between age-classes were greater than between sex-classes. Results suggest that short-term frequency changes are important for auditory evaluation of voice agreeableness. This study opens new research perspectives concerning the importance of prosody during consumer-seller interactions.
Language-at all times
Authors: Nomikou Iris , Schilling Malte , Heller Vivien , Rohlfing Katharina. J.
Published: September 2016

This article discusses the importance of social interaction for the development of the representations for symbolic communication. We suggest that there is no need to distinguish between different representational systems emerging at different stages of development. Instead, we propose that representations are rich right from the beginning of a child’s life, and that they are driven mainly by acting and interacting in the physical and social world. The more variety in a child’s interactional experience (i.e., synchrony, sequentiality, and prediction), the more enriched and abstracted the representations become. We review literature providing evidence for the ways in which infants’ development toward symbolic communication benefits from repeated social (inter)action and consider some implications for computational approaches.
Pretense as deceptive behavioral communication
Authors: Castelfranchi Cristiano
Published: September 2016

Our claim in this paper is that a theory of “pretense” (in all its crucial uses in human society and cognition) can be built only if it is grounded on the general theory of “behavioral implicit communication” (BIC), which is not to be confused with non-verbal communication (with distinct notions being frequently conflated, such as “signs” vs. “messages”, or goal as “intention” vs. goal as “function”). Pretense presupposes some BIC-based human interaction, where a normal, practical behavior is usedforsignifying something, based on a sign that is not a conventional one. In light of BIC interaction theory, one can exploit this sign or message in a deceptive way in order to induce the other to believe that he/she is performing a given behavior or has a given mental state.
RNA silencing approaches for identifying pathogenicity and virulence elements towards engineering crop resistance to plant pathogenic fungi.
Authors: Vinay Panwar Vinay Panwar , McCallum B. , Jordan M. , Loewen M. , Fobert P. , McCartney C. , Bakkeren G.
Published: September 2016

Over the past several years, RNA interference (RNAi) has emerged as a powerful genetic tool that is being exploited not only in fundamental research for the assessment of gene functions, but also in various fields of applied research in medicine and agriculture. In plants, RNAi strategies have the potential to allow manipulation of various aspects of food quality and nutritional content, but also for plant protection. In the study of plant-fungus interactions, a comprehensive understanding of pathogenic mechanisms based on information from genome sequences demands advanced genomics tools and infrastructure. In order to make use of the plethora of information yielded by the rapidly increasing fungal pathogen genome sequencing studies, there is a growing need to achieve gene function assessment amenable to high-throughput techniques. Targeted gene disruption is effective but may not be feasible in certain fungi because of lack of transformation protocols or their life styles. RNAi techniques offer an alternative but, in contrast to other biological systems, only few studies have reported the use of RNAi to explore gene function in plant pathogenic fungi. In this review, we summarize a variety of options using RNAi techniques that have become available to study gene function for high-throughput phenotypic screening of virulence and pathogenicity factors in plant fungi. The identification of such genes can be exploited for the protection of crops against fungal pathogens.
Abundance Estimate for and Habitat Use by Early Juvenile Atlantic Sturgeon within the Delaware River Estuary
Authors: Hale Edward A. , Park Ian A. , Fisher Matthew T. , Wong Richard A. , Stangl Michael J. , Clark John H.
Published: September 2016

The Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus historically supported a significant commercial fishery along the eastern coast of North America. However, overfishing led to substantial population declines with contributions from other anthropogenic impacts, including vessel strikes and contaminants that continue to impede recovery. Our work is the first to estimate the abundance of early juvenile (age 0–1), resident Atlantic Sturgeon in the Delaware River estuary. Using the Schumacher and Eschmeyer mark–recapture estimator for multiple censuses, we estimated 3,656 (95% CI = 1,935–33,041) individuals used the Delaware River estuary as a nursery in 2014. We found no significant change in mean length during the course of our study (November–December), and lengths of age 0–1 Atlantic Sturgeon ranged from 220 to 515 mm TL. Further, using a passive acoustic receiver array, we identified significant habitat areas where age‐0–1 juveniles spend considerable amounts of time; this included the Marcus Hook area and some habitat use downriver and upriver of Marcus Hook at Cherry Island and the Chester Range. Our results support the idea that a spawning population of Atlantic Sturgeon exists in the Delaware River and that some level of early juvenile recruitment is continuing to persist despite current depressed population levels. Understanding trends in abundance, habitat use, and other population metrics for natal river Atlantic Sturgeon will allow for better conservation and management of the species.

Received March 24, 2016; accepted July 10, 2016Published online September 26, 2016
Influence of yttrium addition on reactive sputtered W–Y–N coatings
Authors: Ye F. , Zhao L. , Mu C. , Zhao H.
Published: September 2016

W–Y–N coatings with yttrium content ranging from 0 to 8.2 at.-% were deposited by reactive magnetron sputtering technique. The influence of yttrium content on the structure, oxidation resistance and mechanical properties was investigated. The results show that yttrium atoms substitute tungsten atoms forming the solid solution W–Y–N coatings. All the coatings exhibit a single-phase face-centered cubic structure and the preferred orientation changes from (200) to (111) with yttrium addition. The grain size of W–Y–N coatings decreases with the increase of yttrium content. The oxidation resistance temperature of W–Y–N coatings increases from 500°C at 0 at.-% Y to 730°C at 8.2 at.-% Y. All coatings are in compressive stress state. The hardness, elastic modulus and compressive stress of W–Y–N coatings increase gradually from 28.0, 320 and 1.1 GPa at 0 at.-% Y to 36.0, 385 and 2.1 GPa at 8.2 at.% Y, respectively. The improvement of hardness was attributed to the effect of solid solution strengthening and the grain refinement. In addition, the addition of yttrium content into WN coating also improves its resistance against elastic strain and plastic deformation to failure.
Pre-treatment and electroless Ni–P deposition for surface-modification of tungsten fibres
Authors: Yuan Z. , Liang S. , Zhuo L.
Published: September 2016

In order to improve the surface activity of tungsten fibres (Wf) for subsequent sintering with adjacent powders of W and Cu, autocatalytic Ni–P coatings on Wf were fabricated via electroless deposition in this work. Before electroless deposition, optimal pre-treatment of Wf was determined to increase their surface activity without destroying their internal structure. Afterwards, the deposition rate, microstructure and phase constituents of the plated Ni–P coatings at bath pH values of 5, 6, 7, 8 and 9 were studied systematically. SEM observations showed the presence of uniform and compact grains in the coating and XRD analysis revealed their amorphous or partially crystalline structure. Further sintering of Wf with powders of W and Cu demonstrated the superior interfacial bonding state due to the Ni–P coatings on the Wf surface.
A new NAD+-dependent glyceraldehyde dehydrogenase obtained by rational design of l-lactaldehyde dehydrogenase from Escherichia coli
Authors: Wu Xing , Xu Lin , Yan Ming
Published: September 2016

NAD + -dependent glyceraldehyde dehydrogenases usually had lower activity in the nonphosphorylated Entner–Doudoroff (nED) pathway. In the present study, a new NAD + -dependent glyceraldehyde dehydrogenase was engineered from l-lactaldehyde dehydrogenase of E. coli (EC: 1.2.1.22). Through comparison of the sequence alignment and the active center model, we found that a residue N286 of l-lactaldehyde dehydrogenase contributed an important structure role to substrate identification. By free energy calculation, three mutations (N286E, N286H, N286T) were chosen to investigate the change of substrate specificity of the enzyme. All mutants were able to oxidate glyceraldehyde. Especially, N286T showed the highest activity of 1.1U/mg, which was 5-fold higher than the reported NAD + -dependent glyceraldehyde dehydrogenases, and 70% activity was retained at 55 °C after an hour. Compared to l-lactaldehyde, N286T had a one-third lower Km value to glyceraldehyde.
The effects on plasma L-arginine levels of combined oral L-citrulline and L-arginine supplementation in healthy males
Authors: Suzuki Takashi , Morita Masahiko , Hayashi Toshio , Kamimura Ayako
Published: September 2016

We investigated the effects of combining 1 g of l-citrulline and 1 g of l-arginine as oral supplementation on plasma l-arginine levels in healthy males. Oral l-citrulline plus l-arginine supplementation more efficiently increased plasma l-arginine levels than 2 g of l-citrulline or l-arginine, suggesting that oral l-citrulline and l-arginine increase plasma l-arginine levels more effectively in humans when combined.