bluuebunny/crossref_metadata_2025 huggingface dataset:
Is There a Relationship Between Speech Identification in Noise and Categorical Perception in Children With Dyslexia?
Authors: Calcus Axelle , Lorenzi Christian , Collet Gregory , Colin Cécile , Kolinsky Régine
Published: August 2016

Purpose

Children with dyslexia have been suggested to experience deficits in both categorical perception (CP) and speech identification in noise (SIN) perception. However, results regarding both abilities are inconsistent, and the relationship between them is still unclear. Therefore, this study aimed to investigate the relationship between CP and the psychometric function of SIN perception.

Method

Sixteen children with dyslexia, 16 chronological-age controls, and 16 reading-level controls were evaluated in CP of a voicing continuum and in consonant identification in both stationary and fluctuating noises.

Results

There was a small but significant impairment in speech identification performance of children with dyslexia in stationary noise compared with chronological age–matched controls (but not reading level–matched controls). However, their performance increased in a fluctuating background, hence suggesting normal masking and unmasking effects and preserved sensory processing of speech information. Regarding CP, location of the phoneme boundary differed in the children with dyslexia compared with both control groups. However, scrutinizing individual profiles failed to reveal consistently poor performance in SIN and CP tasks. In addition, there was no significant correlation between CP, SIN perception, and reading scores in the group with dyslexia.

Conclusions

The relationship between the SIN deficit and CP, and how they potentially affect reading in children with dyslexia, remains unclear. However, these results are inconsistent with the notion that children with dyslexia suffer from a low-level temporal processing deficit and rather suggest a role of nonsensory (e.g., attentional) factors in their speech perception difficulties.
Impact of primary networks on the performance of energy harvesting cognitive radio networks
Authors: Zhang Jinghua , Nguyen Nam‐Phong , Zhang Junqing , Garcia‐Palacios Emiliano , Le Ngoc Phuc
Published: August 2016

In this paper, we investigate the effect of of the primary network on the secondary network when harvesting energy in cognitive radio in the presence of multiple power beacons and multiple secondary transmitters. In particular, the influence of the primary transmitter's transmit power on the energy harvesting secondary network is examined by studying two scenarios of primary transmitter's location, i.e., the primary transmitter's location is near to the secondary network and the primary transmitter's location is far from the secondary network. In the scenario where the primary transmitter locates near to the secondary network, although secondary transmitter can be benefit from the harvested energy from the primary transmitter, the interference caused by the primary transmitter suppresses the secondary network performance. Meanwhile, in both scenarios, despite the fact that the transmit power of the secondary transmitter can be improved by the support of powerful power beacons, the peak interference constraint at the primary receiver limits this advantage. In addition, the deployment of multiple power beacons and multiple secondary transmitters can improve the performance of the secondary network. The analytical expressions of the outage probability of the secondary network in the two scenarios are also provided and verified by numerical simulations.
Anti‐windup for a class of partially linearisable non‐linear systems with application to wave energy converter control
Authors: Lekka Angeliki , C. Turner Matthew , P. Menon Prathyush
Published: August 2016

This paper studies the anti‐windup (AW) problem for a certain class of non‐linear systems, in which the plant is globally quadratically stable and also partially linearisable by a suitably chosen non‐linear feedback control law. Three types of AW compensators are proposed for this type of non‐linear system: the first one is a non‐linear extension of the popular linear internal model control (IMC) scheme; the second one has a similar structure to the IMC AW compensator yet is of reduced order and has entirely linear dynamics; and the third one is again a linear AW compensator, but can endow the closed‐loop system with some sub‐optimal performance properties. All three AW compensators are able to provide global exponential stability guarantees for the aforementioned class of systems. This work was inspired by a wave energy application whose dynamics fall into the class of systems studied in this study. Simulation results show the efficacy of the three AW compensators when applied to the wave energy application.
Sampled‐data design for robust control of open two‐level quantum systems with operator errors
Authors: Dong Daoyi , R. Petersen Ian , Wang Yuanlong , Yi Xuexi , Rabitz Herschel
Published: August 2016

This study proposes a sampled‐data design method for robust control of open two‐level quantum systems with operator errors. The required control performance is characterised using the concept of a sliding mode domain related to fidelity, coherence or purity. The authors have designed a control law offline and then utilise it online for a two‐level system subject to decoherence with operator errors in the system model. They analyse three cases of approximate amplitude damping decoherence, approximate phase damping decoherence and approximate depolarising decoherence. They design specific sampling periods for these cases that can guarantee the required control performance.
Adaptive output feedback fault‐tolerant control for MIMO non‐affine non‐linear systems based on disturbance observer
Authors: Ma Zhiyao , Tong Shaocheng , Li Yongming
Published: August 2016

In this study, the fault‐tolerant control problem is investigated for a class of non‐affine output‐constrained multi‐input multiple‐output non‐linear systems with actuator faults. The controlled systems contain unknown non‐linear functions, unknown external disturbance and immeasurable states. The fuzzy logic systems and a robust compensation function are employed to deal with the unknown non‐linear functions and non‐affine non‐linear actuator fault problems. Then, the state observer and the non‐linear disturbance observer are developed for estimating the immeasurable states and unknown compounded disturbance, respectively. By using the barrier Lyapunov function method and in the unified framework of adaptive backstepping output feedback control design, a novel adaptive fuzzy fault‐tolerant controller design scheme is developed. It is shown that all the variables of the closed‐loop system are semi‐globally uniformly bounded. Moreover, the system outputs cannot violate their predefined bounds in the presence of the non‐affine non‐linear faults. A simulation is given to validate the effectiveness of the proposed approach.
Penalised quoted cost based approach on transmission loss allocation for a bilateral contract in deregulated electricity market
Authors: Shafeeque Ahmed K. , Prabhakar Karthikeyan Shanmugam
Published: August 2016

Supplying transmission losses economically under bilateral contract is a challenge for power engineers. In this study, penalised quoted cost (PQC) based approach is proposed where generators will participate for supplying the transmission losses which may be incurred from their customers through their bilateral contracts in a deregulated electricity market. The loss supplying generators will quote the cost and the quantum of real power that can be supplied by them to independent system operator (ISO) in a day‐ahead market. This study presents a lucid approach for loss allocation economically by ranking the loss supplying generators based on their PQC. Penalty factor for each loss supplying generator is calculated using the loss coefficients. ISO will meet the losses due to bilateral contracts in an economical way by selecting the generators with minimum PQC and the associated cost is allocated to the individual transactions based on loss contribution fraction. The proposed algorithm is tested using a sample four‐bus system and IEEE 30 bus system using MATLAB R2014a. This method is based on the participation of generators and their given quotation in transmission loss allocation process. The study gives both the real power loss/cost allocation to the generators and for individual transactions.
Dynamic characteristics and cascaded coordination of limiting‐type SPDs under subsequent negative strokes
Authors: He Yuwei , Fu Zhengcai , Wei Bengang , Chen Jian , Jiang Anfeng
Published: August 2016

Subsequent negative impulses are steep and common in lightning flashes. Under such currents, the dynamic behaviour of metal‐oxide varistors (MOVs) is expected to be significant and would affect the coordination of cascaded surge protective devices (SPDs). This study experimentally investigates the dynamic behaviour of MOVs under steep currents. Based on the dynamic characteristics, simulations are conducted to investigate the coordination of two‐cascaded limiting‐type SPDs with different cascaded combinations, different separation distances, and different loads under subsequent strokes with 0.25/100 μs current waveform. Meanwhile, the results are compared with that under 8/20 and 10/350 μs currents. Experiments are performed to investigate SPD coordination performance under subsequent strokes. The results show that voltages on MOVs of low‐voltage SPDs increase about 6.8‐18.7% under steep currents, compared with that under 8/20 μs current. Thanks to the significantly changed dynamic characteristics, the cascaded SPDs could more easily realise effective coordination under subsequent strokes, compared with that under 8/20 and 10/350 μs currents. Moreover, effective coordination can be achieved in large ranges of separation distances and loads under subsequent strokes. The SPD combinations with clamping voltage of upstream SPD a little higher than downstream SPD have the best behaviour for lightning protection in low‐voltage systems.
Multi‐objective optimal configuration method for a standalone wind–solar–battery hybrid power system
Authors: Ma Gang , Xu Guchao , Chen Yixi , Ju Rong
Published: August 2016

With the development of the energy internet, the standalone wind–solar–battery hybrid power system has gradually become an effective means for the complete utilisation of clean energy for power generation. The allocation of the various types of power sources for ensuring a reliable power supply and for improving the economic efficiency of a system is a crucial issue in the system planning and design stages. The models of the power load and the power sources, containing random components, are first established in this study, based on which the power supply reliability and constraint conditions for the equipment quantities are considered for establishing various evaluation indexes for improving the system performance. Then, according to the combinations of the natural selection particle swarm optimisation algorithm and the weight coefficient transform method, a multi‐objective optimisation algorithm is proposed for optimising the configuration of a standalone wind–solar–battery hybrid power system. Finally, it is demonstrated by an example that the optimisation method not only meets the requirements of the multi‐objective optimisation system but is also significant in reducing energy wastes and fluctuations, cost saving, and in ensuring the reliability of the power supply.
Investigating the hohlraum radiation properties through the angular distribution of the radiation temperature
Authors: Zhang H. , Yang D. , Song P. , Zou S. , Zhao Y. , Li S. , Li Z. , Guo L. , Wang F. , Zheng W. , Gu P. , Pei W. , Zhu S. , Jiang S. , Ding Y.
Published: August 2016

The symmetric radiation drive is essential to the capsule implosion in the indirect drive fusion but is hard to achieve due to the non-uniform radiation distribution inside the hohlraum. In this work, the non-uniform radiation properties of both vacuum and gas-filled hohlraums are studied by investigating the angular distribution of the radiation temperature experimentally and numerically. It is found that the non-uniform radiation distribution inside the hohlraum induces the variation of the radiation temperature between different view angles. The simulations show that both the angular distribution of the radiation temperature and the hohlraum radiation distribution can be affected by the electron heat flux. The measured angular distribution of the radiation temperature is more consistent with the simulations when the electron heat flux limiter fe=0.1. Comparisons between the experiments and simulations further indicate that the x-ray emission of the blow-off plasma is overestimated in the simulations when it stagnates around the hohlraum axis. The axial position of the laser spot can also be estimated by the angular distribution of the radiation temperature due to their sensitive dependence. The inferred laser spot moves closer to the laser entrance hole in the gas-filled hohlraum than that in the vacuum hohlraum, consisting with the x-ray images taken from the framing camera. The angular distribution of the radiation temperature provides an effective way to investigate the hohlraum radiation properties and introduces more constraint to the numerical modeling of the hohlraum experiments.
Weight-lattice discretization of Weyl-orbit functions
Authors: Hrivnák Jiří , Walton Mark A.
Published: August 2016

Weyl-orbit functions have been defined for each simple Lie algebra, and permit Fourier-like analysis on the fundamental region of the corresponding affine Weyl group. They have also been discretized, using a refinement of the coweight lattice, so that digitized data on the fundamental region can be Fourier-analyzed. The discretized orbit function has arguments that are redundant if related by the affine Weyl group, while its labels, the Weyl-orbit representatives, invoke the dual affine Weyl group. Here we discretize the orbit functions in a novel way, by using the weight lattice. A cleaner theory results with symmetry between the arguments and labels of the discretized orbit functions. Orthogonality of the new discretized orbit functions is proved, and leads to the construction of unitary, symmetric matrices with Weyl-orbit-valued elements. For one type of orbit function, the matrix coincides with the Kac-Peterson modular S matrix, important for Wess-Zumino-Novikov-Witten conformal field theory.
Thickness-dependent change in the valence band offset of the SiO2/Si interface studied using synchrotron-radiation photoemission spectroscopy
Authors: Toyoda S. , Oshima M.
Published: August 2016

We have studied the thickness-dependent change in the valence band offset (VBO) of the SiO2/Si(001) interface using synchrotron-radiation photoemission spectroscopy with soft and hard X-rays. The SiO2-film thickness (Tox) and X-ray irradiation time (tirrad) were systematically parameterized to distinguish between the “intrinsic” Tox effects in the VBOs and the “extrinsic” differential charging phenomena in SiO2 films on Si substrates. The results revealed that at a spontaneous time (tirrad ≈ 5 s) that suppresses the differential charging phenomena as much as possible, the experimental VBO abruptly increases as a function of Tox and gradually saturates to the traditional VBO value range determined by the internal photoemission and photoconduction measurements. This effect is not attributed to the differential charging phenomena, but rather it is attributed to the “intrinsic” Tox-dependent change in the VBO. The two possible physical behaviors include electronic polarization and image charge. We have derived the electronic polarization contribution from experimental data by carefully describing the effects of the long-range image charges based on the classical dielectric-screening model.
Prey-predator model with a nonlocal consumption of prey
Authors: Banerjee M. , Volpert V.
Published: August 2016

The prey-predator model with nonlocal consumption of prey introduced in this work extends previous studies of local reaction-diffusion models. Linear stability analysis of the homogeneous in space stationary solution and numerical simulations of nonhomogeneous solutions allow us to analyze bifurcations and dynamics of stationary solutions and of travelling waves. These solutions present some new properties in comparison with the local models. They correspond to different feeding strategies of predators observed in ecology.
High-intensity laser-accelerated ion beam produced from cryogenic micro-jet target
Authors: Gauthier M. , Kim J. B. , Curry C. B. , Aurand B. , Gamboa E. J. , Göde S. , Goyon C. , Hazi A. , Kerr S. , Pak A. , Propp A. , Ramakrishna B. , Ruby J. , Willi O. , Williams G. J. , Rödel C. , Glenzer S. H.
Published: August 2016

We report on the successful operation of a newly developed cryogenic jet target at high intensity laser-irradiation. Using the frequency-doubled Titan short pulse laser system at Jupiter Laser Facility, Lawrence Livermore National Laboratory, we demonstrate the generation of a pure proton beam a with maximum energy of 2 MeV. Furthermore, we record a quasi-monoenergetic peak at 1.1 MeV in the proton spectrum emitted in the laser forward direction suggesting an alternative acceleration mechanism. Using a solid-density mixed hydrogen-deuterium target, we are also able to produce pure proton-deuteron ion beams. With its high purity, limited size, near-critical density, and high-repetition rate capability, this target is promising for future applications.
UV light induced insulator-metal transition in ultra-thin ZnO/TiOx stacked layer grown by atomic layer deposition
Authors: Saha D. , Misra P. , Joshi M. P. , Kukreja L. M.
Published: August 2016

In the present study, atomic layer deposition has been used to grow a series of Ti incorporated ZnO thin films by vertically stacking different numbers (n = 1–7) of ZnO/TiOx layers on (0001) sapphire substrates. The effects of defect states mediated chemisorption of O2 and/OH groups on the electrical properties of these films have been investigated by illuminating the samples under UV light inside a high vacuum optical cryostat. The ultra-thin film having one stacked layer (n = 1) did not show any change in its electrical resistance upon UV light exposure. On the contrary, marginal drop in the electrical resistivity was measured for the samples with n ≥ 3. Most surprisingly, the sample with n = 2 (thickness ∼ 12 nm) showed an insulator to metal transition upon UV light exposure. The temperature dependent electrical resistivity measurement on the as grown film (n = 2) showed insulating behaviour, i.e., diverging resistivity on extrapolation to T→ 0 K. However, upon UV light exposure, it transformed to a metallic state, i.e., finite resistivity at T → 0 K. Such an insulator-metal transition plausibly arises due to the de-trapping of conduction electrons from the surface defect sites which resulted in an upward shift of the Fermi level above the mobility edge. The low-temperature electron transport properties on the insulating film (n = 2) were investigated by a combined study of zero field electrical resistivity ρ(T) and magnetoresistance (MR) measurements. The observed negative MR was found to be in good agreement with the magnetic field induced suppression of quantum interference between forward-going paths of tunnelling electrons. Both ρ(T) and MR measurements provided strong evidence for the Efros-Shklovskii type variable range hopping conduction in the low-temperature (≤40 K) regime. Such studies on electron transport in ultra-thin n-type doped ZnO films are crucial to achieve optimum functionality with long term reliability of ZnO based transparent conducting oxides.
Pressure-induced phase and chemical transformations of lithium peroxide (Li2O2)
Authors: Dunuwille Mihindra , Kim Minseob , Yoo Choong-Shik
Published: August 2016

We present the pressure-induced phase/chemical changes of lithium peroxide (Li2O2) to 63 GPa using diamond anvil cells, confocal micro-Raman spectroscopy, and synchrotron x-ray diffraction. The Raman data show the emergence of the major vibrational peaks associated with O2 above 30 GPa, indicating the subsequent pressure-induced reversible chemical decomposition (disassociation) in dense Li2O2. The x-ray diffraction data of Li2O2, on the other hand, show no dramatic structural change but remain well within a P63/mmc structure to 63 GPa. Nevertheless, the Rietveld refinement indicates a subtle change in the structural order parameter z of the oxygen position O (13, 23, z) at around 35 GPa, which can be considered as a second-order, isostructural phase transition. The nearest oxygen-oxygen distance collapses from 1.56 Å at ambient condition to 1.48 Å at 63 GPa, resulting in a more ionic character of this layered crystal lattice, 3Li++(LiO2)33−. This structural change in turn advocates that Li2O2 decomposes to 2Li and O2, further augmented by the densification in specific molar volumes.
Coaxial printing method for directly writing stretchable cable as strain sensor
Authors: Yan Hai-liang , Chen Yan-qiu , Deng Yong-qiang , Zhang Li-long , Hong Xiao , Lau Woon-ming , Mei Jun , Hui David , Yan Hui , Liu Yu
Published: August 2016

Through applying the liquid metal and elastomer as the core and shell materials, respectively, a coaxial printing method is being developed in this work for preparing a stretchable and conductive cable. When liquid metal alloy eutectic Gallium-Indium is embedded into the elastomer matrix under optimized control, the cable demonstrates well–posed extreme mechanic performance, under stretching for more than 350%. Under developed compression test, the fabricated cable also demonstrates the ability for recovering original properties due to the high flowability of the liquid metal and super elasticity of the elastomeric shell. The written cable presents high cycling reliability regarding its stretchability and conductivity, two properties which can be clearly predicted in theoretical calculation. This work can be further investigated as a strain sensor for monitoring motion status including frequency and amplitude of a curved object, with extensive applications in wearable devices, soft robots, electronic skins, and wireless communication.
Ratchet rectification effect on the translocation of a flexible polyelectrolyte chain
Authors: Mondal Debasish , Muthukumar M.
Published: August 2016

We report a three dimensional Langevin dynamics simulation of a uniformly charged flexible polyelectrolyte chain, translocating through an asymmetric narrow channel with periodically varying cross sections under the influence of a periodic external electric field. When reflection symmetry of the channel is broken, a rectification effect is observed with a favored direction for the chain translocation. For a given volume of the channel unit and polymer length, the rectification occurs below a threshold frequency of the external periodic driving force. We have also observed that the extent of the rectification varies non-monotonically with increasing molecular weight and the strength of geometric asymmetry of the channel. Observed non-monotonicity of the rectification performance has been interpreted in terms of a competition between two effects arising from the channel asymmetry and change in conformational entropy. An analytical model is presented with predictions consistent with the simulation results.
Synthesis of polycaprolactone-titanium oxide multilayer films by nanosecond laser pulses and electrospinning technique for better implant fabrication
Authors: Naghshine Babak B. , Cosman James A. , Kiani Amirkianoosh
Published: August 2016

In this study, a combination of electrospinning and laser texturing is introduced as a novel method for increasing the biocompatibility of metal implants. Besides having a rough laser treated surface, the implant benefits from the high porosity and better wettability of an electrospun fibrous structure, which is a more favorable environment for cell proliferation. Titanium samples were patterned using a nanosecond laser beam and were placed as collectors in an electrospinning machine. They were then soaked in simulated body fluid for four weeks. Energy Dispersive X-ray and X-Ray Diffraction results indicate significantly more hydroxyapatite formation on laser treated samples with nanoscale fibers deposited on their surface. This shows that having a laser treated surface underneath the fibrous layer can improve short-term biocompatibility even before degradation of fibers. The thermal conductivity of the electrospun layer, measured using a Hot Disk Transient Plane Source instrument and computer code, was shown to be considerably lower than that of titanium and very close to bone. The presence of this layer can therefore be beneficial in making the implant more compatible to a biological medium. In case of dental implants, it was shown that this layer can act as a thermal barrier while a hot beverage is consumed and it can decrease the temperature rise by about 60%, which avoids any possible damage to newly formed cells during the healing period.
Photon transfer in a system of coupled superconducting microwave resonators
Authors: Muirhead C. M. , Gunupudi B. , Colclough M. S.
Published: August 2016

A novel scheme is proposed for the study of energy transfer in a pair of coupled thin film superconducting microwave resonators. We show that the transfer could be achieved by modulating the kinetic inductance and that this has a number of advantages over earlier theoretical and experimental schemes, which use modulation of capacitance by vibrating nanobars or membranes. We show that the proposed scheme lends itself to the study of the classical analogues of Rabi and Landau-Zener-Stueckelberg oscillations and Landau-Zener transitions using experimentally achievable parameters. We consider a number of ways in which energy transfer (photon shuttle) between the two resonators could be achieved experimentally.
Room-temperature multiferroic and magnetocapacitance effects in M-type hexaferrite BaFe10.2Sc1.8O19
Authors: Tang Rujun , Zhou Hao , You Wenlong , Yang Hao
Published: August 2016

The room-temperature multiferroic and magnetocapacitance (MC) effects of polycrystalline M-type hexaferrite BaFe10.2Sc1.8O19 have been investigated. The results show that the magnetic moments of insulating BaFe10.2Sc1.8O19 can be manipulated by the electric field at room temperature, indicating the existence of magnetoelectric coupling. Moreover, large MC effects are also observed around the room temperature. A frequency dependence analysis shows that the Maxwell-Wagner type magnetoresistance effect is the dominant mechanism for MC effects at low frequencies. Both the magnetoelectric-type and non-magnetoelectric-type spin-phonon couplings contribute to the MC effects at high frequencies with the former being the dominant mechanism. The above results show that the hexaferrite BaFe10.2Sc1.8O19 is a room-temperature multiferroic material that can be potentially used in magnetoelectric devices.
Room temperature negative differential resistance in terahertz quantum cascade laser structures
Authors: Albo Asaf , Hu Qing , Reno John L.
Published: August 2016

The mechanisms that limit the temperature performance of GaAs/Al0.15GaAs-based terahertz quantum cascade lasers (THz-QCLs) have been identified as thermally activated LO-phonon scattering and leakage of charge carriers into the continuum. Consequently, the combination of highly diagonal optical transition and higher barriers should significantly reduce the adverse effects of both mechanisms and lead to improved temperature performance. Here, we study the temperature performance of highly diagonal THz-QCLs with high barriers. Our analysis uncovers an additional leakage channel which is the thermal excitation of carriers into bounded higher energy levels, rather than the escape into the continuum. Based on this understanding, we have designed a structure with an increased intersubband spacing between the upper lasing level and excited states in a highly diagonal THz-QCL, which exhibits negative differential resistance even at room temperature. This result is a strong evidence for the effective suppression of the aforementioned leakage channel.
Suppression of ion-implantation induced porosity in germanium by a silicon dioxide capping layer
Authors: Tran Tuan T. , Alkhaldi Huda S. , Gandhi Hemi H. , Pastor David , Huston Larissa Q. , Wong-Leung Jennifer , Aziz Michael J. , Williams J. S.
Published: August 2016

Ion implantation with high ion fluences is indispensable for successful use of germanium (Ge) in the next generation of electronic and photonic devices. However, Ge readily becomes porous after a moderate fluence implant (∼1×1015 ion cm−2) at room temperature, and for heavy ion species such as tin (Sn), holding the target at liquid nitrogen (LN2) temperature suppresses porosity formation only up to a fluence of 2×1016 ion cm−2. We show, using stylus profilometry and electron microscopy, that a nanometer scale capping layer of silicon dioxide significantly suppresses the development of the porous structure in Ge during a Sn− implant at a fluence of 4.5×1016 ion cm−2 at LN2 temperature. The significant loss of the implanted species through sputtering is also suppressed. The effectiveness of the capping layer in preventing porosity, as well as suppressing sputter removal of Ge, permits the attainment of an implanted Sn concentration in Ge of ∼15 at.%, which is about 2.5 times the maximum value previously attained. The crystallinity of the Ge-Sn layer following pulsed-laser-melting induced solidification is also greatly improved compared with that of uncapped material, thus opening up potential applications of the Ge-Sn alloy as a direct bandgap material fabricated by an ion beam synthesis technique.
Synthesis of zirconium oxynitride in air under DC electric fields
Authors: Morisaki Nobuhiro , Yoshida Hidehiro , Matsui Koji , Tokunaga Tomoharu , Sasaki Katsuhiro , Yamamoto Takahisa
Published: August 2016

We synthesized zirconium oxynitride from yttria-stabilized zirconia (YSZ) in air by applying DC electric fields that produced a controlled electric current in the specimen. When YSZ was heated under an applied DC electric field, the electric current of the specimen steeply increased at a critical temperature, called a flash event, during flash sintering. By keeping the electric current of the specimen constant during the flash event and then holding the specimen at the critical temperature, YSZ was transformed into zirconium oxynitride under the optimal conditions of 50 V/cm, 500 mA, and 1000 °C. We confirmed that zirconium oxynitride formed using high-resolution transmission electron microscopy, electron energy-loss spectroscopy, and energy-dispersive spectrometry. To convert oxides to nitrides, reducing conditions are necessary to form excess oxygen vacancies. Our technique produced the strong reducing conditions necessary to form nitrides from the oxides by delivering a controlled electric current to the specimen.
Expanding a dairy business affects business and financial risk
Authors: Sinnett A. , Ho C. K. M. , Malcolm B.
Published: August 2016

Australia’s dairy farmers have expanded the size of their businesses in response to rising costs and falling prices. Dairy farmers pursuing increases in wealth encounter a greater risk associated with increased size, complexity and output. It is the consequences of risk that matter. Risk in a farm business can be partitioned into either business risk or financial risk. Previous research on changes to farm systems has primarily focussed on the impact of business risk, with less regard for financial risk. Our analysis has shown that expanding a farm business is likely to increase financial risk more than business risk. Before committing to the decision to expand their businesses, dairy farmers have control over the amount they borrow and, thus, some control over the exposure of their businesses to additional financial risk. Knowing the extra risk associated with extra debt is additional information that contributes to more informed decisions. In this research, an approach to assessing the change in business and financial risk associated with different expansion options is demonstrated.
Fatty acid profile, carcass traits and meat quality of Nellore steers following supplementation with various lipid sources
Authors: Carvalho Isabela P. C. , Fiorentini Giovani , Lage Josiane F. , Messana Juliana D. , Canesin Roberta. C. , Rossi Luis G. , Reis Ricardo A. , Berchielli Telma T.
Published: August 2016

The aim of the present study was to evaluate the fatty acid composition of meat and subcutaneous fat, carcass traits and meat quality of Nellore steers fed diets supplemented with various lipid sources. Forty-five young bulls, with average bodyweight of 441 ± 30 kg, were allotted into 10 paddocks, with five treatments, each consisting of two paddocks. The bulls were randomly assigned into one of the following five treatments, which consisted of four lipid sources: palm oil (PO), linseed oil, rumen protected fat (soybean-based oil), whole soybean, and a control (without additional fat). Trial duration was 120 days, which included 30 days of adaptation. Supplements were offered daily at 10 g/kg bodyweight per day. Dietary supplements for providing additional fat were formulated to consist of 10% ether extract. Lipid sources did not significantly affect the average daily gain (P = 0.797) or dressing percentage (P = 0.663). Supplementation with PO increased the concentrations of lauric acid (P = 0.036) and myristic acid (P < 0.001) in the muscle and subcutaneous fat. Animals supplemented with linseed oil had significantly higher concentrations of conjugated linolenic acid in the meat (P = 0.036) and fat (P = 0.049) than did control animals. In the present study, the use of various lipid sources in dietary supplements of grazing cattle during finishing period did not affect carcass traits or physical attributes of beef. This absence of statistical significance may be related to the minimum number of repeat paddocks (2) per treatment. Thus, differences that can have a practical significance were not evidenced by statistical analysis. The inclusion of PO and protected fatty acids derived from soybean oil (rumen-protected fat) is not recommended as a method to improve the lipid profile of meat and subcutaneous fat of Nellore cattle.
Trends in grain production and yield gaps in the high-rainfall zone of southern Australia
Authors: Robertson Michael , Kirkegaard John , Peake Allan , Creelman Zoe , Bell Lindsay , Lilley Julianne , Midwood Jon , Zhang Heping , Kleven Sue , Duff Chris , Lawes Roger , Riffkin Penny
Published: August 2016

The high-rainfall zone (HRZ) of southern Australia is the arable areas where annual rainfall is between 450 and 800 mm in Western Australia and between 500 and 900 mm in south-eastern Australia, resulting in a growing-season length of 7–10 months. In the last decade, there has been a growing recognition of the potential to increase crop production in the HRZ. We combined (1) a survey of 15 agricultural consultants, each of whom have ~40–50 farmer clients across the HRZ, (2) 28 farm records of crop yields and area for 2000–2010, (3) 86 wheat and 54 canola yield observations from well managed experiments, and (4) long-term simulated crop yields at 13 HRZ locations, to investigate recent trends in crop production, quantify the gap between potential and actual crop yields, and consider the factors thought to limit on-farm crop yields in the HRZ. We found in the past 10 years a trend towards more cropping, particularly in WA, an increased use of canola, and advances in the adaptation of germplasm to HRZ environments using winter and longer-season spring types. Consultants and the farm survey data confirmed that the rate of future expansion of cropping in the HRZ will slow, especially when compared with the rapid changes seen in the 1990s. In Victoria, New South Wales and South Australia the long-term water-limited potential yield in HRZ areas, as measured by experimental yields, consultant estimates and simulations for slow developing spring cultivars of wheat and canola was 5–6 and 2–3 t/ha for a decile 5 season. For Western Australia it was 4–5 and 2–3 t/ha, where yields were less responsive to good seasons than in the other states. The top performing farmers were achieving close to the water-limited potential yield. There are yield advantages of ~2 t/ha for ‘winter’ over ‘spring’ types of both wheat and canola, and there is scope for better adapted germplasm to further raise potential yield in the HRZ. Consultants stated that there is scope for large gains in yield and productivity by encouraging the below-average cropping farmers to adopt the practices and behaviours of the above-average farmers. The scope for improvement between the below- and above-average farmers was 1–3 t/ha for wheat and 0.5–1.5 t/ha for canola in a decile 5 season. They also stated that a lack of up-to-date infrastructure (e.g. farm grain storage) and services is constraining the industry’s ability to adopt new technology. Priorities for future research, development and extension among consultants included: overcoming yield constraints where growing-season rainfall exceeds 350 mm; adaptation of winter and long-season spring types of cereals and canola and management of inputs required to express their superior yield potential; and overcoming barriers to improved planning and timeliness for crop operations and adoption of technology.
A BUKI (Building up Knowledge Initiative) focussed on antimony’s environmental chemistry
Authors: Filella Montserrat
Published: August 2016

Environmental contextScientific knowledge is continuously built up based on research results, and relies on their efficient and accurate dissemination. Using antimony as an example, a system is proposed that combines ease of access with focussed reviews while keeping track of all published work. This system, termed BUKI (Building Up Knowledge Initiative) is a collaborative approach based on the combination of a web-based platform and the elaboration of systematic reviews.
AbstractThe increasing difficulties experienced by the scientific community in efficiently constructing knowledge from the flood of data being continuously produced are discussed and a concrete solution – a BUKI (Building Up Knowledge Initiative) – proposed for research on the environmental chemistry of antimony. A BUKI is a collaborative approach based on the combination of a web-based platform and the elaboration of systematic reviews. The antimony BUKI described here aims to improve our knowledge of antimony in environmental systems but also to stir up discussion about how research works nowadays and to provide a model for the development of other BUKIs.
Birth-site selection and timing of births in American bison: effects of habitat and proximity to anthropogenic features
Authors: Kaze Joshua , Whiting Jericho C. , Freeman Eric D. , Bates Steven B. , Larsen Randy T.
Published: August 2016

Context Human activities can affect habitat selection by ungulates during parturition. Minimising human–wildlife conflicts during the birthing period can be critical in national and state parks that receive high numbers of human visitors. American bison (Bison bison) are an iconic species in North America, and many conservation herds of bison occupy national and state parks and wildlife refuges. Aims We investigated timing of births and birth-site selection of bison on Antelope Island State Park, Utah, at multiple spatial scales to determine the relative influence of surrounding vegetation, topography and distance to anthropogenic features (i.e. trails, roads or structures) on selection of birthing habitat. Methods We used vaginal implant transmitters to determine timing of births and to identify birth sites of bison. We used logistic regression within a model-selection framework to differentiate between birth sites and random locations, based on potential explanatory variables. We then used model-averaged coefficients to produce and project a GIS model of birthing habitat onto Antelope Island. Key results During 2010 and 2011, we quantified variables surrounding 35 birth sites and 101 random sites. Variables in top models of birth-site selection for bison included landscape curvature and elevation, averaged at a 500-m radius around birth sites, as well as distance to nearest trails, roads or structures. Five-fold cross validation (rho = 0.89; P < 0.05) indicated that these variables successfully predicted birth sites of bison in our study area; 80% of 41 births occurred in April (range = March 22 to May 20). Conclusions Bison selected areas for birthing with concave topography and increased elevation that were away from trails, roads or structures. Implications Our GIS model of birthing habitat, and data concerning timing of births, provide a map of high-probability birthing areas and a time of year at which human access could be limited to reduce disturbance from recreational activity. This approach could aid managers in minimising conflict between recreationists and parturient bison in other national and state parks and wildlife refuges.
Hedgehog-dependent E3-ligase Midline1 regulates ubiquitin-mediated proteasomal degradation of Pax6 during visual system development
Authors: Pfirrmann Thorsten , Jandt Enrico , Ranft Swantje , Lokapally Ashwin , Neuhaus Herbert , Perron Muriel , Hollemann Thomas
Published: August 2016

Significance

The first morphological sign of vertebrate eye formation is the appearance of eye vesicles on both sides of the ventral diencephalon, which primarily originate from a uniform Pax6-positive eye field. A key regulator for this process, which coincides with the establishment of the proximo-distal axis of the eye with eyestalk and retina, is the morphogen Shh. Shh induces the expression of
pax2
, which represses
pax6
in the presumptive eyestalk region. Here, we report on the identification of the E3-ligase Mid1, which is induced by Shh and targets transcription factor Pax6 for proteasomal degradation. Our findings might provide insight into a mechanism, in which a morphogen initiates the degradation of a transcription factor to form sharp boundaries of gene expression.
Fundamental structures of dynamic social networks
Authors: Sekara Vedran , Stopczynski Arkadiusz , Lehmann Sune
Published: August 2016

Significance

We study the dynamic network of real world person-to-person interactions between approximately 1,000 individuals with 5-min resolution across several months. There is currently no coherent theoretical framework for summarizing the tens of thousands of interactions per day in this complex network, but here we show that at the right temporal resolution, social groups can be identified directly. We outline and validate a framework that enables us to study the statistical properties of individual social events as well as series of meetings across weeks and months. Representing the dynamic network as sequences of such meetings reduces the complexity of the system dramatically. We illustrate the usefulness of the framework by investigating the predictability of human social activity.
Cytosolic activation of cell death and stem rust resistance by cereal MLA-family CC–NLR proteins
Authors: Cesari Stella , Moore John , Chen Chunhong , Webb Daryl , Periyannan Sambasivam , Mago Rohit , Bernoux Maud , Lagudah Evans S. , Dodds Peter N.
Published: August 2016

Significance

Stem rust caused by the fungus
Puccinia graminis
f. sp.
tritici
(
Pgt
) remains the major disease threat to wheat production. The Sr33 and Sr50 resistance proteins protect wheat against a broad spectrum of field isolates of
Pgt
and are closely related to the barley powdery mildew-resistance protein MLA10. Like MLA10, Sr33 and Sr50 possess signaling N-terminal domains that self-associate
in planta
and initiate cell-death signaling from the cytosol. However, Sr33 induces disease-resistance signaling from the cytosol but not from the nucleus of wheat cells, suggesting cytosolic activation of both cell death and stem rust resistance.
Vibrio cholerae
biofilm growth program and architecture revealed by single-cell live imaging
Authors: Yan Jing , Sharo Andrew G. , Stone Howard A. , Wingreen Ned S. , Bassler Bonnie L.
Published: August 2016

Significance

Biofilms are surface-associated bacterial communities embedded in an extracellular matrix. Connections between biofilm architectural, material, and mechanical features have never been systematically studied at the individual cell level due to inadequate optical resolution. Here, we develop imaging, experimental, and modeling tools to analyze living, growing bacterial biofilms at single-cell resolution. We discover that
Vibrio cholerae
biofilms undergo a 2D-to-3D transition as a consequence of directional cell division and anisotropic pressure caused by cell-to-surface adhesion. Moreover, deletion of a single gene responsible for cell-to-cell adhesion changes the biofilm growth mode from directional cell growth to expansion caused by the extracellular matrix. The technology reported here enables future studies of single-cell gene expression in bacterial communities.
Cotton and textiles industries in Tanzania: the failures of liberalisation
Authors: Coulson Andrew
Published: August 2016

This article uses the story of cotton cultivation in Tanzania to analyse critically the processes of liberalisation and expose the failure of markets to reward quality production. It starts by summarising the technological requirements to grow the crop. It then shows how cotton was central to industrialisation, in Britain and elsewhere. In Tanzania, cotton is grown on small farms and so the article then summarises how small farmers make choices and minimise risks. This creates the context for outline histories, first of cotton growing, and then of textile industries in Tanzania, before turning to the impact of structural adjustment and liberalisation in the late 1980s and 1990s which led to increases in production but losses in quality and price. The article draws conclusions from this about the role of agriculture in processes of economic transformation and the need for institutions which represent the economic interests of small farmers.
Lionel Cliffe and the generation(s) of Zimbabwean politics
Authors: Moore David
Published: August 2016

Lionel Cliffe’s idea of ‘generations’ was a way of understanding the structure/agency divide and internecine struggles among Zimbabwe’s nascent ruling classes during its liberation struggle. Here, its utility as an analytical tool on factional conflict is assessed. Cliffe’s own involvement in the Zimbabwe African National Union’s history is also examined as a lens on its generational and ideological contradictions. Further, archival evidence of the British state’s observations of Mugabe illustrates how he fused the contradictions of age cohorts, points of entry into the struggle, political philosophy and international dimensions, and suggests, too, the difficulties of outsiders’ understanding of complex struggles.
Village land politics and the legacy of ujamaa
Authors: Greco Elisa
Published: August 2016

The paper explores the legacies of ujamaa for Tanzanian village land management through the analysis of ethnographic data. The first section considers the ujamaa legacies for Tanzanian village administrative and political institutions and the weight of past top-down politics. In the second section, village land politics are investigated in the light of the reform of the land laws in order then to underline the role of village authorities in collective land claims and to illustrate how village land allocations occur in practice. The third section analyses data from three villages to reflect on the salience of village land politics and Village Land Use Plans. Ujamaa leaves its legacy in the continuity of a potential for democratisation from below resisting the continuity of authoritarianism and centralised decision making from above.