bluuebunny/crossref_metadata_2025 huggingface dataset:
Heterogeneous vision chip and LBP‐based algorithm for high‐speed tracking
Authors: Yang Jie , Shi Cong , Liu Liyuan , Wu Nanjian
Published: March 2014

A local binary pattern (LBP)‐based tracking algorithm and a novel heterogeneous vision chip architecture that implements the algorithm in high speed are proposed. The algorithm is more robust than previously reported high‐speed tracking algorithms. The proposed vision chip architecture adopts multiple levels of parallel processors to execute the algorithm in pixel‐parallel and patch‐parallel ways. Experimental results show that the proposed implementation can achieve 1000 fps robust tracking.
3D frequency selective surface for stable angle of incidence
Authors: Lee I.G. , Hong I.P.
Published: March 2014

A three‐dimensional frequency selective surface (3D‐FSS) that provides stability for an angle of incidence and miniaturised unit cell size is presented. The proposed 3D‐FSS is easy to fabricate and is implemented using via holes in a multilayer printed circuit board structure. Frequency transmission characteristics for different angles of both TE and TM polarisations are presented through simulations. The proposed structure was fabricated so as to verify the simulation results. The comparisons between the simulation and the measured results show good agreement. The results also show that the proposed 3D‐FSS can provide better frequency stability for different incidence angles and polarisations as well as miniaturised unit cell size.
High‐performance microstrip directional coupler for radio‐astronomical receivers at cryogenic temperature
Authors: Valente G. , Montisci G. , Mariotti S.
Published: March 2014

A microstrip directional coupler with high directivity is proposed for microwave applications requiring a weak coupling factor. This component has been used in the L‐band radio‐astronomical receiver of the Sardinia radio telescope. To improve the performance of the receiver, the operating temperature is lowered to 20 K. An in‐house cryostat has been manufactured to perform measurements on the directional coupler, and very good agreement with the design specification is achieved.
Using directly modulated DFBs without power penalty in low‐cost and high‐power budget coherent access networks
Authors: Presi M. , Corsini R. , Artiglia M. , Ciaramella E.
Published: March 2014

The operation of an extended power budget long reach access network is experimentally demonstrated using commercially available small form pluggable directly modulated transmitters and a simplified coherent receiver free from digital signal processing and phase‐locked loops. An ad‐hoc choice of photodiode bandwidth allows no penalty compared with external modulation based transmitters.
Study on MIMO transmission using orthogonal directivities obtained from higher order microstrip antenna modes
Authors: Arai M. , Seki T. , Hiraga K. , Sakamoto K. , Toshinaga H. , Nakagawa T. , Uehara K.
Published: March 2014

A simpler MIMO transmission method using orthogonal directivities is proposed. In future wireless communication systems, higher data rates will be required since large amounts of data will be transmitted and received. MIMO technology is useful for achieving higher data rates. However, since MIMO detection becomes complicated when the number of antennas becomes large, a simpler method should be considered. To solve this problem, the present authors proposed a spatial division method using orthogonal directivities. This previously proposed method to N streams is expanded transmission for application to much higher data rate systems. Furthermore, using higher order antenna modes at the same frequency to more easily obtain orthogonal directivities is proposed. To evaluate the proposed method, it is confirmed by numerical analysis that the capacity of the proposed method increases without MIMO detection when the number of antennas becomes large.
Extending the bandwidth of low‐noise microwave amplifier through digital assist
Authors: Stewart D. , Saavedra C. E.
Published: March 2014

The 3 dB bandwidth of a low‐noise amplifier (LNA) is increased by 23% from a range of 1–6.7 GHz to a range of 1–8.25 GHz through digital assist. The LNA has a multi‐stage topology and the gate bias voltages are dynamically optimised in real‐time to obtain the best gain and noise figure as a function of the signal input frequency.
Band‐notched UWB rectangular dielectric resonator antenna
Authors: Wang Yong Feng , Denidni T.A. , Zeng Qing Sheng , Wei Gao
Published: March 2014

A new ultra‐wideband (UWB) rectangular dielectric resonator antenna (DRA) with band‐stop performance is proposed. Two symmetrical short‐circuited strips together with a slot etched in the feeding patch are introduced to form the notched band. The design principles of the proposed methods are described in detail. The measured result demonstrates that the proposed DRA achieves an UWB bandwidth from 3.6 to 12 GHz for a voltage standing wave ratio <2 with a notched band from 5.1 to 6.0 GHz.
Experimental study of LTE signals as illuminators of opportunity for passive bistatic radar applications
Authors: Salah A.A. , Raja Abdullah R.S.A. , Ismail A. , Hashim F. , Abdul Aziz N.H.
Published: March 2014

Passive radars utilising illuminators of opportunity are being actively studied in the field of radar. In the last few years, many illuminator sources have been employed for passive radar applications. However, there have been no published results on the use of the long‐term evolution (LTE) signal as a novel source for passive radar applications. For the first time an experimental investigation into the feasibility of LTE‐based passive radars for detecting a moving target is presented. A theoretical analysis was conducted on a captured LTE signal in the atmosphere. This was then followed by a field experiment. The preliminary results show that the LTE signal is capable of being an illuminator for passive radars.
Design and discussion of a broadband cross‐dipole with high isolation and low cross‐polarisation utilising strong mutual coupling
Authors: Bao Zengdi , Zong Xianzheng , Nie Zaiping , Yang Shiwen
Published: March 2014

A broadband cross‐dipole with high isolation and low cross‐polarisation for base station applications in mobile wireless communications is presented in this study. By skillfully utilising the strong mutual coupling between the two dipoles, very good impedance match, sufficiently high isolation and low cross‐polarisation can be achieved simultaneously. The measured results show that a more than 54% impedance bandwidth for standing wave ratio (SWR) < 1.5 from 1.695 to 2.95 GHz is achieved, within which the isolation is larger than 35 dB and the cross‐polarisation is less than −34 dB. As a desirable advantage, the input impedance of the antenna can be changed within certain limits by properly adjusting the configuration, thus the antenna can be fed directly by 50‐Ω coaxial cables without the aid of impedance transformers. Particularly, besides the designing and the optimising work, the mechanisms for high isolation and low cross‐polarisation as well as the method to adjust the input impedance are also discussed from a new point of view, which are also appropriate for other cross‐dipole with the similar patterns.
Exploring Multi-Actor Value Creation in IT Service Processes
Authors: Lempinen Heikki , Rajala Risto
Published: March 2014

Organizational information technology (IT) needs are served through increasingly complex configurations of people, technologies, organizations, and shared information. Ideally, an organizational IT service is valuable for both the providers and users of systems and solutions. However, mutually beneficial outcomes may be difficult to achieve within the configurations through which IT services are delivered. We suggest that analyzing stakeholder interplay in IT service processes helps us to understand how information systems (IS) organizations can be leveraged to co-create business value. Through a qualitative empirical inquiry, we explore IT service realization in two case organizations. Through our analysis we find that value creation builds on orchestrated social action among the different stakeholder groups involved. Joint value creation in IT service processes hence calls for specific network leadership and resource integration capabilities from the IS organization. The paper enriches the current understanding of business value creation in IT services by infusing the service logic with traditional IT management perspectives. The findings highlight that the extent to which the IS organization can learn to facilitate the interaction between the essential actors in an ‘IT service system’ and leverage user-perceived value throughout the service process will ultimately determine its success or failure.
Non-equilibrium study of spin wave interference in systems with both Rashba and Dresselhaus (001) spin-orbit coupling
Authors: Chen Kuo-Chin , Su Yu-Hsin , Chen Son-Hsien , Chang Ching-Ray
Published: March 2014

We study the electron spin transport in two dimensional electron gas (2DEG) system with both Rashba and Dresselhaus (001) spin-orbital coupling (SOC). We assume spatial behavior of spin precession in the non-equilibrium transport regime, and study also quantum interference induced by non-Abelian spin-orbit gauge field. The method we adopt in this article is the non-equilibrium Green's function within a tight binding framework. We consider one ferromagnetic lead which injects spin polarized electron to a system with equal strength of Rashba and Dresselhaus (001) SOC, and we observe the persistent spin helix property. We also consider two ferromagnetic leads injecting spin polarized electrons into a pure Dresselhaus SOC system, and we observe the resultant spin wave interference pattern.
Thermal modeling of head disk interface system in heat assisted magnetic recording
Authors: Vemuri Sesha Hari , Min Kim Hyung , Seung Chung Pil , Jhon Myung S.
Published: March 2014

A thorough understanding of the temperature profiles introduced by the heat assisted magnetic recording is required to maintain the hotspot at the desired location on the disk with minimal heat damage to other components. Here, we implement a transient mesoscale modeling methodology termed lattice Boltzmann method (LBM) for phonons (which are primary carriers of energy) in the thermal modeling of the head disk interface (HDI) components, namely, carbon overcoat (COC). The LBM can provide more accurate results compared to conventional Fourier methodology by capturing the nanoscale phenomena due to ballistic heat transfer. We examine the in-plane and out-of-plane heat transfer in the COC via analyzing the temperature profiles with a continuously focused and pulsed laser beam on a moving disk. Larger in-plane hotspot widening is observed in continuously focused laser beam compared to a pulsed laser. A pulsed laser surface develops steeper temperature gradients compared to continuous hotspot. Furthermore, out-of-plane heat transfer from the COC to the media is enhanced with a continuous laser beam then a pulsed laser, while the temperature takes around 140 fs to reach the bottom surface of the COC. Our study can lead to a realistic thermal model describing novel HDI material design criteria for the next generation of hard disk drives with ultra high recording densities.
Molecular dynamics simulation of nucleation in the binary mixture n-nonane/methane
Authors: Braun Stephan , Kalikmanov Vitaly , Kraska Thomas
Published: March 2014

Vapor-liquid nucleation in the binary system n-nonane/methane is investigated by molecular dynamics simulation. The supersaturation is achieved by cooling down the system during the expansion in order to closely mimic the real process. Binary clusters formed by nucleation are frequently inhomogeneous objects in which components are not well mixed. By studying high-pressure nucleation and cluster growth in the n-nonane/methane mixture, we demonstrate the role of structuring effects in these processes. At typical simulation conditions—pressure 60 bar, temperature 240 K, and nucleation rate ∼1026 cm−3s−1—the mole fraction of methane in the critical cluster reaches 80 percent, which is much higher than its equilibrium value in the bulk liquid at the same pressure and temperature. These observations are supported by the recently formulated coarse-grained theory for binary nucleation as well as by the experimental observations.
The Landau free energy of hard ellipses obtained from microscopic simulations
Authors: Luo Alan M. , Sagis Leonard M. C. , Ilg Patrick
Published: March 2014

Systems of two-dimensional hard ellipses of varying aspect ratios and packing fractions are studied by Monte Carlo simulations in the generalised canonical ensemble. From this microscopic model, we extract a coarse-grained macroscopic Landau-de Gennes free energy as a function of packing fraction and orientational order parameter. We separate the free energy into the ideal orientational entropy of non-interacting two-dimensional spins and an excess free energy associated with excluded volume interactions. We further explore the isotropic-nematic phase transition using our empirical expression for the free energy and find that the nature of the phase transition is continuous for the aspect ratios we studied.
Spontaneous symmetry breaking discovers the formation of aeroplane-like ZnO nanocrystals
Authors: Zhou Yan , Zhang Junyan , Zhang Bin , Qiang Li , Da Yuqing , Su Gang , Li Jiangong
Published: March 2014

Although symmetry breaking is widely realized as one of the most powerful tools in modern scientific researches, it is unclear how symmetry breaking plays its role in nanocosm. Here, we show a correlation between spontaneous symmetry breaking and the formation of nanocrystals. In our experiments, some ZnO nanocrystals, including ZnO tetrapods, rod-based tetrapods, and aeroplane-like crystals, presented with specific structures and symmetries leading to an unexpected process of spontaneous symmetry breaking. According to the rule of spontaneous symmetry breaking, a hypothesis was proposed that the aeroplane-like nanocrystals might be resulted from the unequal development of the crystal twinnings. Subsequent work supported this hypothesis and proved the dramatic effect of spontaneous symmetry breaking. This work applies the rule of spontaneous symmetry breaking to the formation mechanisms for nanocrystals and highlights the causal contribution of spontaneous symmetry breaking to the intricate behaviors of the particles at nanoscale.
Picosecond spin relaxation in low-temperature-grown GaAs
Authors: Uemura M. , Honda K. , Yasue Y. , Lu S. L. , Dai P. , Tackeuchi A.
Published: March 2014

The spin relaxation process of low-temperature-grown GaAs is investigated by spin-dependent pump and probe reflectance measurements with a sub-picosecond time resolution. Two very short carrier lifetimes of 2.0 ps and 28 ps, which can be attributed to nonradiative recombinations related to defects, are observed at 10 K. The observed spin polarization shows double exponential decay with spin relaxation times of 46.2 ps (8.0 ps) and 509 ps (60 ps) at 10 K (200 K). The observed picosecond spin relaxation, which is considerably shorter than that of conventional GaAs, indicates the strong relevance of the Elliott-Yafet process as the spin relaxation mechanism. For the first (second) spin relaxation component, the temperature and carrier density dependences of the spin relaxation time indicate that the Bir-Aronov-Pikus process is also effective at temperatures between 10 K and 77 K, and that the D'yakonov-Perel’ process is effective between 125 K (77 K) and 200 K.
Tunable hyperbolic metamaterials utilizing phase change heterostructures
Authors: Krishnamoorthy Harish N. S. , Zhou You , Ramanathan Shriram , Narimanov Evgenii , Menon Vinod M.
Published: March 2014

We present a metal-free tunable anisotropic metamaterial where the iso-frequency surface is tuned from elliptical to hyperbolic dispersion by exploiting the metal-insulator phase transition in the correlated material vanadium dioxide (VO2). Using VO2-TiO2 heterostructures, we demonstrate the transition in the effective dielectric constant parallel to the layers to undergo a sign change from positive to negative as the VO2 undergoes the phase transition. The possibility to tune the iso-frequency surface in real time using external perturbations such as temperature, voltage, or optical pulses creates new avenues for controlling light-matter interaction.
Magnetic reconnection in a comparison of topology and helicities in two and three dimensional resistive magnetohydrodynamic simulations
Authors: Čemeljić M. , Huang R.-Y.
Published: March 2014

Through a direct comparison between numerical simulations in two and three dimensions, we investigate topological effects in reconnection. A simple estimate on increase in reconnection rate in three dimensions by a factor of 2, when compared with a two-dimensional case, is confirmed in our simulations. We also show that both the reconnection rate and the fraction of magnetic energy in the simulations depend linearly on the height of the reconnection region. The degree of structural complexity of a magnetic field and the underlying flow is measured by current helicity and cross-helicity. We compare results in simulations with different computational box heights.
Fabrication and optical characteristics of phosphor-free InGaN nanopyramid white light emitting diodes by nanospherical-lens photolithography
Authors: Wu Kui , Wei Tongbo , Zheng Haiyang , Lan Ding , Wei Xuecheng , Hu Qiang , Lu Hongxi , Wang Junxi , Luo Yi , Li Jinmin
Published: March 2014

A novel nanopattern technique of nanospherical-lens photolithography is introduced to fabricate the InGaN nanopyramid white (NPW) light-emitting diodes (LEDs) by selective area growth. Highly ordered NPW LED arrays are achieved after optimizing the growth conditions. It is found that the NPW LEDs vary from warm white light to cool with the increase in growth temperature. For the cool white NPW LEDs, the spectrum is similar to the conventional white LEDs obtained from the blue LEDs combined with yellow phosphors. The blue emission originates from the upper sidewalls of nanopyramids, and yellow light is mainly emitted from the lower ridges with respect to the base of nanopyramids. Furthermore, simulation shows that the light extraction efficiency of NPW LEDs is about 4 times higher compared with conventional ones, and the escape cone is as much as 85° due to their three-dimensional nanopyramid structures. These observations suggest that the proposed phosphor-free NPW LEDs may have great potential for highly efficient white lighting.
Complex temperature evolution of the electronic structure of CaFe2As2
Authors: Adhikary Ganesh , Biswas Deepnarayan , Sahadev Nishaina , Bindu R. , Kumar Neeraj , Dhar S. K. , Thamizhavel A. , Maiti Kalobaran
Published: March 2014

Employing high resolution photoemission spectroscopy, we investigate the temperature evolution of the electronic structure of CaFe2As2, which is a parent compound of high temperature superconductors—CaFe2As2 exhibits superconductivity under pressure as well as doping of charge carriers. Photoemission results of CaFe2As2 in this study reveal a gradual shift of an energy band, α away from the chemical potential with decreasing temperature in addition to the spin density wave (SDW) transition induced Fermi surface reconstruction across SDW transition temperature. The corresponding hole pocket eventually disappears at lower temperatures, while the hole Fermi surface of the β band possessing finite p orbital character survives till the lowest temperature studied. These results, thus, reveal signature of complex charge redistribution among various energy bands as a function of temperature.
Pressure effect on elastic, lattice dynamic and superconducting behaviour of yttrium sulfide: A first principle study
Authors: Sahoo B. D. , Joshi K. D. , Gupta Satish C.
Published: March 2014

First principles calculations have been carried out to analyze structural, elastic, and dynamic stability of yttrium sulphide (YS) under hydrostatic compression. The comparison of enthalpies of rocksalt type (B1) and CsCl type cubic (B2) structures determined as a function of compression suggests the B1 → B2 transition at ∼49 GPa (the same transition occurs at ∼48 GPa at 300 K). Various physical quantities such as zero pressure equilibrium volume, bulk modulus, and pressure derivative of bulk modulus have been derived from the theoretically determined equation of state. The single crystal elastic constants derived from the energy strain method agree well with the experimental values. The activation barrier between B1 and B2 phases calculated at transition point is ∼17/mRy/f.u. Our lattice dynamic calculations show that at ambient condition, the B1 phase is lattice dynamically stable, and frequencies of phonon modes in different high symmetry directions of Brillouin zone agrees well with experimental values. The B2 phase also is dynamical stable at ambient condition as well as at ∼49 GPa, supporting our static lattice calculation. The effect of temperature on volume and bulk modulus of the YS in B1 phase has also been examined. The superconducting temperature of ∼2.78 K determine at zero pressure agrees well with experimental data. The effect of pressure is found to suppress the superconducting nature of this material.
Ferroelectric and ferromagnetic properties of epitaxial BiFeO3-BiMnO3 films on ion-beam-assisted deposited TiN buffered flexible Hastelloy
Authors: Xiong J. , Matias V. , Tao B. W. , Li Y. R. , Jia Q. X.
Published: March 2014

Growth of multifunctional thin films on flexible substrates is of great technological significance since such a platform is needed for flexible electronics. In this study, we report the growth of biaxially aligned (BiFeO3)0.5:(BiMnO3)0.5 [BFO-BMO] films on polycrystalline Hastelloy by using a biaxially aligned TiN as a seed layer deposited by ion-beam-assisted deposited and a La0.7Sr0.3MnO3 (LSMO) as a buffer layer deposited by pulsed laser deposition. The LSMO is used not only as a buffer layer but also as the bottom electrode of the BFO-BMO films. X-ray diffraction showed that the BFO-BMO films are biaxially oriented along both in-plane and out-of-plane directions. The BFO-BMO films on flexible metal substrates showed a polarization of 22.9 μC/cm2. The magnetization of the BFO-BMO/LSMO is 62 emu/cc at room temperature.
Three-dimensional flow contrast imaging of deep tissue using noncontact diffuse correlation tomography
Authors: Lin Yu , Huang Chong , Irwin Daniel , He Lian , Shang Yu , Yu Guoqiang
Published: March 2014

This study extended our recently developed noncontact diffuse correlation spectroscopy flowmetry system into noncontact diffuse correlation tomography (ncDCT) for three-dimensional (3-D) flow imaging of deep tissue. A linear array of 15 photodetectors and two laser sources connected to a mobile lens-focusing system enabled automatic and noncontact scanning of flow in a region of interest. These boundary measurements were combined with a finite element framework for DCT image reconstruction implemented into an existing software package. This technique was tested in computer simulations and using a tissue-like phantom with anomaly flow contrast design. The cylindrical tube-shaped anomaly was clearly reconstructed in both simulation and phantom. Recovered and assigned flow contrast changes in anomaly were found to be highly correlated: regression slope = 1.00, R2 = 1.00, and p < 10−5 in simulation and regression slope ≥ 0.97, R2 ≥ 0.96, and p < 10−3 in phantom. These results exhibit promise of our ncDCT technique for 3-D imaging of deep tissue blood flow heterogeneities.
Evolution of multiple dielectric responses and relaxor-like behaviors in pure and nitrogen-ion-implanted (Ba, Sr)TiO3 thin films
Authors: Gao Y. H. , Yang J. , Shen H. , Sun J. L. , Meng X. J. , Chu J. H.
Published: March 2014

Multiple dielectric responses are comparatively investigated in the pure and nitrogen-ion-implanted (Ba, Sr)TiO3 (BST) films. Larger diffusive degree of phase transition and more relaxor-like features than those of pure BST films are observed in implanted ones, where the long-range-dipolar-correlated-orders were further segregated into local polar orders after the implantation. Moreover, the implanted films possess a transition from local reorientations of groups of dipoles induced nearly constant-loss (NCL) type to oxygen vacancies (Vo) hopping type conduction at high temperature. Whereas, pure films behave as NCL type conduction along with a dielectric relaxation, which arises from the motions of defect complexes Vo2+–Ti3+.
Investigation of nano Pt and Pt-based alloys electrocatalysts for direct methanol fuel cells and their properties
Authors: Suo Chunguang , Zhang Wenbin , Shi Xinghua , Ma Chuxia
Published: March 2014

The electrocatalysts used in micro direct methanol fuel cell (μDMFC), such as Pt/C and Pt alloy/C, prepared by liquid-phase NaBH4 reduction method have been investigated. XC-72 (Cobalt corp. Company, U.S.A) is chosen as the activated carrier for the electrocatalysts to keep the catalysts powder in the range of several nanometers. The XRD, SEM, EDX analyses indicated that the catalysts had small particle size in several nanometers, in excellent dispersed phase and the molar ratio of the precious metals was found to be optimal. The performances of the DMFCs using cathodic catalyst with Pt percentage of 30wt% and different anodic catalysts (Pt-Ru, Pt-Ru-Mo) were tested. The polarization curves and power density curves of the cells were measured to determine the optimal alloy composition and condition for the electrocatalysts. The results showed that the micro direct methanol fuel cell with 30wt% Pt/C as the cathodic catalyst and n(Pt):n(Ru):n(Mo) = 3:2:2 PtRuMo/C as the anodic catalyst at room temperature using 2.0mol/L methanol solution has the best performances.
A Spatial-Indexing Model for Measuring Neighbourhood-Level Land-Use and Transport Integration
Authors: Dur Fatih , Yigitcanlar Tan , Bunker Jonathan
Published: March 2014

Significant attention has been given in urban policy literature to the integration of land-use and transport planning and policies—with a view to curbing sprawling urban form and diminishing externalities associated with car-dependent travel patterns. By taking land-use and transport interaction into account, this debate mainly focuses on how a successful integration can contribute to societal well-being, providing efficient and balanced economic growth while accomplishing the goal of developing sustainable urban environments and communities. The integration is also a focal theme of contemporary urban development models, such as smart growth, liveable neighbourhoods, and new urbanism. Even though available planning policy options for ameliorating urban form and transport-related externalities have matured—owing to growing research and practice worldwide—there remains a lack of suitable evaluation models to reflect on the current status of urban form and travel problems or on the success of implemented integration policies. In this study we explore the applicability of indicator-based spatial indexing to assess land-use and transport integration at the neighbourhood level. For this, a spatial index is developed by a number of indicators compiled from international studies and trialled in Gold Coast, Queensland, Australia. The results of this modelling study reveal that it is possible to propose an effective metric to determine the success level of city plans considering their sustainability performance via composite indicator methodology. The model proved useful in demarcating areas where planning intervention is applicable, and in identifying the most suitable locations for future urban development and plan amendments. Lastly, we integrate variance-based sensitivity analysis with the spatial indexing method, and discuss the applicability of the model in other urban contexts.
Labilities of aqueous nanoparticulate metal complexes in environmental speciation analysis
Authors: Town Raewyn M. , van Leeuwen Herman P.
Published: March 2014

Environmental context Sorbing nanoparticles can have a significant effect on the speciation of small ions and molecules in the environment. The reactivity of nanoparticulate-bound species can differ significantly from that of their molecular or colloidal counterparts. We present a conceptual framework that describes the chemodynamics and lability of nanoparticulate metal complexes over a wide range of experimental timescales and environmental conditions. Abstract An inherent property of a dispersion of charged nanoparticles is that their charges and reactive sites are spatially confined to the particle body which is at a different potential from that in the bulk medium. This feature has important consequences for the reactivity of nanoparticulate complexants: the diffusive rate of reactant supply is lower as compared to molecular complexants, whereas the local concentration of reactant ions may be enhanced if the particle’s electric field has the opposite charge sign. These effects are most dramatic for soft nanoparticles for which the electrostatic accumulation mechanisms operate on a 3-D level. We show how the interplay of these effects governs the reactivity of charged nanoparticulate metal complexes (M-NPs) at the surface of an analytical speciation sensor. A theoretical framework is presented that describes the lability of M-NP species over a range of effective timescales for different electrochemical and other dynamic speciation analysis techniques. The concepts are illustrated by electrochemical stripping data on metal complexes with natural soft nanoparticles of humic acid.
Jasmonic acid is associated with resistance to twospotted spider mites in diploid cotton (Gossypium arboreum)
Authors: Miyazaki Junji , Stiller Warwick N. , Truong Thy T. , Xu Qian , Hocart Charles H. , Wilson Lewis J. , Wilson Iain W.
Published: March 2014

The twospotted spider mite (Tetranychus urticae Koch) is capable of dramatically reducing the yield of cotton crops and is often difficult and expensive to control. This study investigated and compared two important plant hormones, jasmonic acid (JA) and salicylic acid (SA), as constitutive and/or induced defence response components in a mite susceptible commercial cotton cultivar, Sicot 71 (Gossypium hirsutum L.) and a resistant diploid cotton BM13H (Gossypium arboreum L.). Foliar application of JA and methyl jasmonate (MeJA) reduced the mite population and leaf damage but application of other potential elicitors, SA and methyl salicylate (MeSA) did not. The concentrations of JA and SA in leaf tissues of induced and non-induced Sicot 71 and BM13H were quantified by liquid chromatography coupled to electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS). The JA content was constitutively higher in BM13H than Sicot 71 and also highly induced by mite infestation in BM13H but not in Sicot 71. However, SA was not significantly induced in either BM13H or Sicot 71. The expression levels of JA related genes, LOX, AOS and OPR were measured by quantitative PCR and elevated expression levels of JA related genes were detected in mite-infested BM13H. Therefore, JA and MeJA were implicated as key biochemical components in both the constitutive and induced defence responses of BM13H to spider mites.
Fish navigation of large dams emerges from their modulation of flow field experience
Authors: Goodwin R. Andrew , Politano Marcela , Garvin Justin W. , Nestler John M. , Hay Duncan , Anderson James J. , Weber Larry J. , Dimperio Eric , Smith David L. , Timko Mark
Published: March 2014

Significance

Whereas adult salmon swimming upstream through a ladder visibly illustrates the challenge a dam presents to fish returning home to spawn, the downstream passage of juveniles swimming toward the ocean is often a greater, although more unseen, challenge to their survival. Decades of work have identified many factors that affect fish behavior near dams, but why downstream passage structures may work well at one dam but not at another is poorly understood. We use a computer model to show that observed downstream passage patterns could result from a generic strategy that fish may use to navigate flow field obstacles. Our findings identify environmental and biological factors warranting further evaluation for sustaining native species amid economic development.
Vortex filament method as a tool for computational visualization of quantum turbulence
Authors: Hänninen Risto , Baggaley Andrew W.
Published: March 2014

The vortex filament model has become a standard and powerful tool to visualize the motion of quantized vortices in helium superfluids. In this article, we present an overview of the method and highlight its impact in aiding our understanding of quantum turbulence, particularly superfluid helium. We present an analysis of the structure and arrangement of quantized vortices. Our results are in agreement with previous studies showing that under certain conditions, vortices form coherent bundles, which allows for classical vortex stretching, giving quantum turbulence a classical nature. We also offer an explanation for the differences between the observed properties of counterflow and pure superflow turbulence in a pipe. Finally, we suggest a mechanism for the generation of coherent structures in the presence of normal fluid shear.
Direct observation of Kelvin waves excited by quantized vortex reconnection
Authors: Fonda Enrico , Meichle David P. , Ouellette Nicholas T. , Hormoz Sahand , Lathrop Daniel P.
Published: March 2014

Quantized vortices are key features of quantum fluids such as superfluid helium and Bose–Einstein condensates. The reconnection of quantized vortices and subsequent emission of Kelvin waves along the vortices are thought to be central to dissipation in such systems. By visualizing the motion of submicron particles dispersed in superfluid
4
He, we have directly observed the emission of Kelvin waves from quantized vortex reconnection. We characterize one event in detail, using dimensionless similarity coordinates, and compare it with several theories. Finally, we give evidence for other examples of wavelike behavior in our system.
Andreev reflection, a tool to investigate vortex dynamics and quantum turbulence in
3
He-B
Authors: Fisher Shaun Neil , Jackson Martin James , Sergeev Yuri A. , Tsepelin Viktor
Published: March 2014

Andreev reflection of quasiparticle excitations provides a sensitive and passive probe of flow in superfluid
3
He-B. It is particularly useful for studying complex flows generated by vortex rings and vortex tangles (quantum turbulence). We describe the reflection process and discuss the results of numerical simulations of Andreev reflection from vortex rings and from quantum turbulence. We present measurements of vortices generated by a vibrating grid resonator at very low temperatures. The Andreev reflection is measured using an array of vibrating wire sensors. At low grid velocities, ballistic vortex rings are produced. At higher grid velocities, the rings collide and reconnect to produce quantum turbulence. We discuss spatial correlations of the fluctuating vortex signals measured by the different sensor wires. These reveal detailed information about the formation of quantum turbulence and about the underlying vortex dynamics.
Vortices and turbulence in trapped atomic condensates
Authors: White Angela C. , Anderson Brian P. , Bagnato Vanderlei S.
Published: March 2014

After more than a decade of experiments generating and studying the physics of quantized vortices in atomic gas Bose–Einstein condensates, research is beginning to focus on the roles of vortices in quantum turbulence, as well as other measures of quantum turbulence in atomic condensates. Such research directions have the potential to uncover new insights into quantum turbulence, vortices, and superfluidity and also explore the similarities and differences between quantum and classical turbulence in entirely new settings. Here we present a critical assessment of theoretical and experimental studies in this emerging field of quantum turbulence in atomic condensates.
Fine-scale ecological and economic assessment of climate change on olive in the Mediterranean Basin reveals winners and losers
Authors: Ponti Luigi , Gutierrez Andrew Paul , Ruti Paolo Michele , Dell’Aquila Alessandro
Published: March 2014

Significance

Inability to determine reliably the direction and magnitude of change in natural and agro-ecosystems due to climate change poses considerable challenge to their management. Olive is an ancient ubiquitous crop having considerable ecological and socioeconomic importance in the Mediterranean Basin. We assess the ecological and economic impact of projected 1.8 °C climate warming on olive and its obligate pest, the olive fly. This level of climate warming will have varying impact on olive yield and fly infestation levels across the Mediterranean Basin, and result in economic winners and losers. The analysis predicts areas of decreased profitability that will increase the risk of abandonment of small farms in marginal areas critical to soil and biodiversity conservation and to fire risk reduction.
Revealing mesoscopic structural universality with diffusion
Authors: Novikov Dmitry S. , Jensen Jens H. , Helpern Joseph A. , Fieremans Els
Published: March 2014

Significance

A major challenge in the physical and life sciences is to see the invisible by quantifying the structure of materials and living tissues below nominal imaging resolution. Measurement of molecular diffusion performed at a macroscopic level is a common noninvasive structural probe. Interpreting its results involves identifying which structural features, out of a myriad of parameters, most strongly affect the diffusion coefficient. Here we address this ill-posed problem by classifying media into a relatively small number of universality classes, based on the nature of long-range structural correlations. We show that the time dependence of a macroscopic diffusion coefficient distinguishes between these classes. Using this approach, we identify dominant restrictions to MRI-measured water diffusion in muscles and in cortical gray matter.
Normal acquisition of expertise with greebles in two cases of acquired prosopagnosia
Authors: Rezlescu Constantin , Barton Jason J. S. , Pitcher David , Duchaine Bradley
Published: March 2014

Significance

The leading accounts of face recognition are the face-specific view and the expertise view. The face-specific account claims upright faces are processed by brain mechanisms specialized for faces, whereas the expertise hypothesis claims faces are processed by mechanisms engaged by fine-grained discrimination of the object of expertise. The effects of expertise on visual recognition have been studied in the laboratory using greebles (objects designed to place face-like demands on recognition mechanisms), and behavioral and neural markers characteristic of face processing have been reported for greebles after training. Here we present compelling evidence that performance with greebles does not depend on face recognition mechanisms. Two individuals with acquired prosopagnosia displayed normal greeble learning despite severely impaired face performance. These results support the face-specific account.
Biomechanics of milk extraction during breast-feeding
Authors: Elad David , Kozlovsky Pavel , Blum Omry , Laine Andrew F. , Po Ming Jack , Botzer Eyal , Dollberg Shaul , Zelicovich Mabel , Ben Sira Liat
Published: March 2014

Significance

We have resolved a century-long scientific controversy and demonstrated with a 3D biophysical model that infants suck breast milk by subatmospheric pressures and not by mouthing the nipple–areola complex to induce a peristaltic-like extraction mechanism. Analysis of ultrasound (US) movies demonstrated that the anterior tongue, which is wedged between the nipple–areola complex and the lower lips, moves as a rigid body with the cycling motion of the mandible, while the posterior section of the tongue undulates like a peristaltic wave, which is essential for swallowing. The computational simulations of breast-feeding successfully mimicked the dynamic characteristics observed in US imaging and also predicted the subatmospheric pressure required to draw the nipple–areola complex into the infant mouth during latch-on.
Critical roles of isoleucine-364 and adjacent residues in a hydrophobic gate control of phospholipid transport by the mammalian P4-ATPase ATP8A2
Authors: Vestergaard Anna L. , Coleman Jonathan A. , Lemmin Thomas , Mikkelsen Stine A. , Molday Laurie L. , Vilsen Bente , Molday Robert S. , Dal Peraro Matteo , Andersen Jens Peter
Published: March 2014

Significance

Membranes of eukaryotic cells retain an essential asymmetric distribution of phospholipids in the two leaflets, which depends on the translocation by P4-ATPases (flippases) of specific phospholipids across the lipid bilayer. Severe diseases result from flippase mutations. Flippases are closely related to ion pumps like Na
+
,K
+
-ATPase and Ca
2+
-ATPase, yet the large size of the lipid substrate compared with inorganic cations raises the fundamental issue of how the flippases accomplish lipid transport. We characterized the mammalian flippase ATP8A2, applying mutagenesis and specific functional assays in combination with computational studies. We identify a unique putative lipid transport pathway through the flippase protein and propose a plausible translocation mechanism, which is both distinct from and related to the well-characterized cation transport mechanisms.
Persistence of skin-resident memory T cells within an epidermal niche
Authors: Zaid Ali , Mackay Laura K. , Rahimpour Azad , Braun Asolina , Veldhoen Marc , Carbone Francis R. , Manton Jonathan H. , Heath William R. , Mueller Scott N.
Published: March 2014

Significance

Tissue-resident memory T cells (T
RM
) form in the skin where they are retained and can protect against subsequent infection. Using a combination of intravital imaging and mathematical modeling of skin T
RM
that form after cutaneous herpes simplex virus 1 infection, we reveal that these memory T cells persist at the site of infection for the life of a mouse owing to slow random migration. We also report that T
RM
compete with dendritic epidermal γδ T cells in skin for local survival signals, suggesting that T cells compete for space within an epidermal niche.
Crystal structure of EML1 reveals the basis for Hsp90 dependence of oncogenic EML4-ALK by disruption of an atypical β-propeller domain
Authors: Richards Mark W. , Law Edward W. P. , Rennalls La’Verne P. , Busacca Sara , O’Regan Laura , Fry Andrew M. , Fennell Dean A. , Bayliss Richard
Published: March 2014

Significance

Echinoderm microtubule-associated protein (EMAP)-like (EML) proteins normally function in the cytoskeleton. In some lung cancers, genetic abnormalities generate the oncogenic fusion protein EML4-anaplastic lymphoma kinase (ALK) on which the cancer cells depend for survival. We have determined the molecular structure of a conserved, tubulin-binding region of EML1 that reveals an unexpected protein fold. This region is disrupted in ∼70% of EML4-ALK fusions found in patients, causing them to be sensitive to drugs that target Hsp90, a cellular factor that stabilizes misfolded protein. Our findings will potentially enable more effective, stratified therapy of
EML4-ALK
nonsmall cell lung cancer and suggest that the truncation of a globular domain at the translocation breakpoint may prove generally predictive of Hsp90 inhibitor sensitivity in cancers driven by fusion oncogenes.
Homolog detection using global sequence properties suggests an alternate view of structural encoding in protein sequences
Authors: Scheraga Harold A. , Rackovsky S.
Published: March 2014

Significance

A Fourier-based sequence distance function for proteins is presented, which exhibits high accuracy in structural homology searches. The significance of this work lies in the fact that there has been no independent method available until now with which to compare homologies generated by sequence alignment. The method avoids the limitations of alignment and has the potential to uncover new classes of homologs and to give significant insight into the organization of the protein universe. Because it is very rapid and able to compare arbitrarily large groups of sequences simultaneously and exactly, it also has great promise as a general tool in biomedical research.
When making pie, all ingredients must be chilled. Including you
Authors: Diemer Stefan , Frobenius Maximiliane
Published: March 2014

The present study describes food blogs as a genre of computer-mediated communication (CMC). The combined approach of corpus linguistic and pragmatic methods reveals the characteristics of food blogs as a hybrid genre that mixes elements from various other discourse types. Lexical and syntactic analyses depict the use and frequencies of (1) CMC related phenomena: innovative vocabulary and spelling; (2) food related jargon: specialized vocabulary, grammatical patterns; (3) phenomena related to spoken interaction: discourse markers, hedges and address. The pragmatic analysis reviews these elements in their blog context. They contribute to creating an audience directed text through features such as humor, repetition and expert knowledge. We thus provide evidence that one of the main goals of this discourse type is interaction and describe how this interaction is systematically achieved.
Passionate about food
Authors: Chiaro Delia
Published: March 2014

Despite the nation’s poor reputation in terms of cuisine, cookery shows abound on UK television with Jamie Oliver and Nigella Lawson being two of TV’s most popular chefs. Following a brief overview of popular cookery programs broadcast in the UK over the past fifty years, this essay will focus on Jamie and Nigella through a description of a series of linguistic features adopted by each, such as their idiosyncratic uses of terminology when giving instructions; modes of interaction with the audience and expressions of emotion. It will emerge that the chefs’ performances, especially in terms of language, take front stage with respect to the dishes they present.
The flavors of multi-ethnic North American literatures
Authors: Fellner Astrid M.
Published: March 2014

This paper analyzes culinary remembrances by Asian Canadian, Latina, and Caribbean writers, investigating the multivalent meaning of food in literary texts. In ethnic literature, food figures as a powerful symbol of ethnicity, becoming a significant site where identity construction, community building and social critique can take place. Descriptions of culinary practices set in motion thoughts on belonging and national identity, offering affective encounters with the past. Culinary nostalgia, this paper argues, allows ethnic subjects to identify as ethnic via their relationship to food, opening up ways of engaging the politics of identity. Using a language through which to imagine alterity, these narratives provide a space for reflections on the complex interplay of “here” and “there,” of “home” and “away.”
“Bon Appétit, Lion City”
Authors: Serwe Stefan , Ong Kenneth Keng Wee , Ghesquière Jean Francois
Published: March 2014

In multilingual Singapore, French can frequently be found in the names of local food retailers and restaurants. This study attempts to investigate the form and function of French in these business names. By considering which meanings French expresses in the local corporate context, the reasons behind the use of French will be discussed. At the heart of the analysis is a corpus of 47 names found on shop signs in different locations of Singapore. Results suggest a link between form, the type of food retail business, and the food served. Functionally, French expresses cultural and social meanings, while stressing individual and collective identities. We present evidence for the use of French as an emergent commercial register peculiar to Singapore.