bluuebunny/crossref_metadata_2025 huggingface dataset:
Multifunctionalized polyurethane–polyurea nanoparticles: hydrophobically driven self-stratification at the o/w interface modulates encapsulation stability
Authors: Rocas Pau , Fernández Yolanda , Schwartz Simó , Abasolo Ibane , Rocas Josep , Albericio Fernando
Published: August 2015

The combination of an amphiphilic and a hydrophobic reactive prepolymer promotes the self-stratification of the whole PUUa NP by hydrophobic interactions.
AAC Considerations for Individuals With Angelman Syndrome
Authors: Calculator Stephen N.
Published: August 2015

Purpose

To provide an overview of communication characteristics exhibited by individuals with Angelman Syndrome (AS) and special considerations associated with the design and implementation of augmentative and alternative communication (AAC) programs.

Method

Results of recent studies exploring individuals' uses of AAC are reviewed, with particular emphasis on factors related to individuals' acceptance and successful uses of AAC systems.

Results

Not applicable

Conclusion

Despite their inconsistent access to practices previously found to foster individuals' acceptance of AAC systems, individuals with AS demonstrate the ability to use AAC systems, including high-tech AAC devices, successfully.
Communication Programming for Learners With CHARGE Syndrome: Augmenting Comprehension and Expression
Authors: Bashinski Susan M.
Published: August 2015

“Communication, communication, communication,” Hartshorne, Hefner, Davenport, and Thelin's groundbreaking book, CHARGE Syndrome (2011), opens with these words and continues, “For 25 years, this has been our mantra when asked what it is that children with CHARGE syndrome need […] The biggest barrier to ultimate success for individuals with CHARGE is communication” (p. xi).
Relay transmit power allocation for distributed‐space–time block code cognitive small cell networks
Authors: Ndong Massa , Fujii Takeo
Published: August 2015

Small cell networks enhance spectrum efficiency by handling the indoor traffic of mobile networks on a frequency‐reuse operation. Since most of the current mobile traffic happen in indoor, the authors introduce a prioritisation shift by imposing a limitation on the outage generated by the outdoor mobile system to the indoor small cells. The prioritisation shift consists of setting an outage probability threshold limitation on the macrocell system which is classically considered as a primary system. In this study, they consider downlink spectrum sharing between a system consisting of small cells and a macrocell with relays. The relays constitute a distributed‐space‐time block code (STBC) relaying for the outdoor system terminals. New closed‐form expressions are derived to validate the proposed bit error rate (BER) function used in their optimisation algorithm considering STBC with unequal branch SNR. They propose a joint transmit antenna selection and power allocation which minimises the proposed BER. The proposed optimisation yields a dynamic selection of the relays with power control pertaining to the outdoor mobile terminal performance. The simulation results show that their proposal exhibits a better BER compared with the conventional Alamouti STBC with equal power allocation.
Hybrid global navigation satellite systems, differential navigation satellite systems and time of arrival cooperative positioning based on iterative finite difference particle filter
Authors: Georges Hassana Maigary , Wang Dong , Xiao Zhu , Chen Jie
Published: August 2015

In this study, the authors develop a novel solution for hybrid global navigation satellite systems, differential navigation satellite systems and time of arrival cooperative positioning (CP) based on iterative finite difference particle filter (PF) in GNSS‐terrestrial navigation and challenging environments. A variant of finite difference filters called divided difference filter (DDF) was used as an importance density for particle generation. Various proposal distributions have been proposed to improve the performance of PF, but practical situations have encouraged the researchers to design better candidate for proposal distributions in order to gain better performance especially for hybrid CP system. The author's proposed method named hybrid cooperative particle‐based DDF solves the problem of linearisation of non‐linear functions that are based on Jacobian matrices which often cannot be applied in practical applications of non‐linear estimation techniques. An iterative reweighted information filter based on the extended Kalman filter (KF) was integrated during the measurement update phase to smooth the output of the DDF used for particles update. Simulation results based on a realistic outdoor scenario show that the proposed solution outperforms some well‐known state‐of‐the‐art in hybrid CP systems, such as hybrid cooperative unscented KF in terms of accuracy and availability and provides good performance even in challenging conditions.
Coupled thermal and hydraulic algebraic models for an open self‐ventilated induction machine
Authors: Malumbres Jose Angel , Satrustegui Marco , Elosegui Ibon , Martínez‐Iturralde Miguel
Published: August 2015

The prediction of the thermal behaviour of electric motors in the early stages of their design is a critical factor for reducing time and cost in the design process. In complex machine topologies such as open self‐ventilated machines, there are several phenomenas to take into account in order to predict the correct thermal behaviour of the machine. In this study, a thermal model coupled with a hydraulic model is presented. These models provide information of the thermal behaviour of the machine. First, the complete thermal circuit is described, with some emphasis in the specially modelled parts. Then, the heat transfer coefficients for each surface inside the machine are presented, by the use of dimensionless correlations that avoids the need of previous knowledge. Moreover, the hydraulic model of the machine is studied, and also the coupling methodology between the two models is described for both steady state and transient calculations. Finally, the results from the model are validated using the data from two experimental runs, the first one with constant torque and speed, and the other with variable power, in a standardised service cycle, with a difference in the rotor bars and the stator winding below ±10°C.
Evaluation of the effectiveness of portable variable message signs in work zones in United Arab Emirates
Authors: Ahmed Kamran , Al‐Zoubi Khalid , Siddiqui Muhammed Abrar , Anas Mohammed
Published: August 2015

Highway work zones pose a higher risk of crashes due to an increase in the complexity of driving task and driver information. An effective way to impart variable pertinent information to the drivers based on local conditions is the use of variable message signs (VMSs). This study focuses on the effectiveness of portable VMSs (PVMSs) in altering speeds using data obtained during a field deployment, as well as qualitative data from road users and construction workers collected using surveys. Speed, volume, and classification data were collected before and during the installation of the PVMS. A questionnaire was developed related to the PVMS performance, which was used to gauge the perception of drivers and construction workers for the purpose of qualitative analysis. The field data and the survey results were correlated to study the impact of PVMS in reducing the speed of vehicles. The survey results indicated that the drivers as well as the construction workers perceived PVMS to have a positive effect on safety and that PVMS provides reliable information. However, the quantitative analysis of vehicular speeds before and during the installation of PVMS revealed no statistically significant change in speeds.
Analysis of open‐slot antenna radiation pattern using spherical wave expansion
Authors: Belmkaddem Kawtar , Vuong Tan Phu , Rudant Lionel
Published: August 2015

This work explores the impact of the ground plane on a λ/2 open‐slot antenna using the spherical wave expansion in the far‐field zone. In terms of equivalent radiating sources, the nature of the open‐slot antenna radiation pattern is not well assessed. This study shows that for small ground planes, open‐slot antenna is a multiple source antenna.
Statistical analysis on the bandwidth of a dual frequency textile antenna
Authors: Sundarsingh Esther Florence , Ramalingam Vimal Samsingh , Kanagasabai Malathi
Published: August 2015

A novel dual frequency, wide band textile antenna has been proposed. A slot cut out of a regular rectangular patch revealing a vertical dumbbell‐shaped conducting region resonates at global positioning system (L1 and L3) and time division duplex long term evolution fourth generation bands. The radiation efficiencies of the antenna at the lower and upper resonant frequencies are 96 and 88%, respectively. The antenna is fabricated using double side silver coated conductive fabric on a denim substrate and experimentally validated. The textile antenna resonates from 1.435 to 1.81 GHz and from 2.755 to 3.19 GHz. The antenna has a bandwidth of 375 and 435 MHz, that is, fractional bandwidth of 25.08 and 12.6% at the lower and upper bands, respectively. The fabricated antenna is then subjected to bending, shear, stretching deformations and their effects on the bandwidth of the antenna are analysed using analysis of variance method. The significant factors and their percentage contribution on the bandwidth are also determined using the F‐test. Finally, an empirical equation is derived for the designed antenna to compute the bandwidth and the results are validated.
Experimental validation of coherent multiple‐input multiple‐output radar antenna patterns
Authors: Moo Peter W. , Sévigny Pascale , Laneve Tony
Published: August 2015

This study specifies the antenna radiation patterns of a linear array radar operating in a phased array configuration and in two colocated multiple‐input multiple‐output (MIMO) configurations. The MIMO‐1 configuration uses orthogonal transmission on all elements, while the MIMO‐2 configuration uses orthogonal transmission on the two end elements. The theoretical two‐way antenna radiation patterns are derived for all three configurations. Field experiments with an eight‐element, X‐band linear array radar and trihedral targets are then described. The experimental mainbeam patterns are shown to match those of the theoretical patterns. MIMO‐1 is shown to have the same two‐way radiation pattern as that of the phased array radar configuration. Compared with MIMO‐1 and phased array, MIMO‐2 has enhanced angle estimation accuracy, lower gain, and higher sidelobes while only requiring two orthogonal waveforms on transmit.
Deploying swarm intelligence in medical imaging identifying metastasis, micro‐calcifications and brain image segmentation
Authors: al‐Rifaie Mohammad Majid , Aber Ahmed , Hemanth Duraiswamy Jude
Published: August 2015

This study proposes an umbrella deployment of swarm intelligence algorithm, such as stochastic diffusion search for medical imaging applications. After summarising the results of some previous works which shows how the algorithm assists in the identification of metastasis in bone scans and microcalcifications on mammographs, for the first time, the use of the algorithm in assessing the CT images of the aorta is demonstrated along with its performance in detecting the nasogastric tube in chest X‐ray. The swarm intelligence algorithm presented in this study is adapted to address these particular tasks and its functionality is investigated by running the swarms on sample CT images and X‐rays whose status have been determined by senior radiologists. In addition, a hybrid swarm intelligence‐learning vector quantisation (LVQ) approach is proposed in the context of magnetic resonance (MR) brain image segmentation. The particle swarm optimisation is used to train the LVQ which eliminates the iteration‐dependent nature of LVQ. The proposed methodology is used to detect the tumour regions in the abnormal MR brain images.
Charging method of micro heat pipe for high‐power light‐emitting diode
Authors: Li Congming , Luo Yi , Zhou Chuanpeng , Shan Qing , Wang Xiaodong
Published: August 2015

Since high precision of working fluid charging is key to the evaluation of thermal performance, a novel perfusion method of a micro heat pipe (MHP) is presented. The MHP has a length of 26 mm, width of 20 mm and a thickness of ∼2.2 mm. The predetermined quantity of perfusion is 25 or 35 μl. Small volume and large capillary force render conventional vacuum perfusion methods quite impractical. To realise microscale and high precision of perfusion, the method of combining vacuum perfusion using a peristaltic pump and weight comparison before and after working fluid charging was used. The charging deviation of the method was <2 μl. After perfusion and sealing, the thermal performance testing of a MHP, which is engineered in light‐emitting diode (LED) heat dissipation, was conducted and the input power varied from 1 to 7 W. The results show that high‐power LEDs can reach the status of heat balance and can work steadily, and the maximum deviations of actual and simulated temperatures are 4.5 and 5.1°C, respectively, and the relative errors are 6.1 and 7.3%. Therefore, this perfusion method can be used for the working fluid perfusion of the MHP and makes it feasible for use in packaging manufacture of heat pipes.
Contact resonance atomic force microscopy imaging in air and water using photothermal excitation
Authors: Kocun Marta , Labuda Aleksander , Gannepalli Anil , Proksch Roger
Published: August 2015

Contact Resonance Force Microscopy (CR-FM) is a leading atomic force microscopy technique for measuring viscoelastic nano-mechanical properties. Conventional piezo-excited CR-FM measurements have been limited to imaging in air, since the “forest of peaks” frequency response associated with acoustic excitation methods effectively masks the true cantilever resonance. Using photothermal excitation results in clean contact, resonance spectra that closely match the ideal frequency response of the cantilever, allowing unambiguous and simple resonance frequency and quality factor measurements in air and liquids alike. This extends the capabilities of CR-FM to biologically relevant and other soft samples in liquid environments. We demonstrate CR-FM in air and water on both stiff silicon/titanium samples and softer polystyrene-polyethylene-polypropylene polymer samples with the quantitative moduli having very good agreement between expected and measured values.
Growth condition dependence of photoluminescence polarization in (100) GaAs/AlGaAs quantum wells at room temperature
Authors: Iba Satoshi , Saito Hidekazu , Watanabe Ken , Ohno Yuzo , Yuasa Shinji
Published: August 2015

We conducted systematic measurements on the carrier lifetime (τc), spin relaxation time (τs), and circular polarization of photoluminescence (Pcirc) in (100) GaAs/AlGaAs multiple quantum wells grown by molecular beam epitaxy (MBE). The τc values are strongly affected by MBE growth conditions (0.4–9 ns), whereas the τs are almost constant at about 0.13 ns. The result suggests that spin detection efficiency [τs/(τc + τs)], which is expected to be proportional to a steady-state Pcirc, is largely dependent on growth condition. We confirmed that the Pcirc has similar dependence on growth condition to those of τs/(τc + τs) values. The study thus indicates that choosing the appropriate growth condition of the QW is indispensable for obtaining a high Pcirc from a spin-polarized light-emitting diode (spin-LED).
Relaxation rates in the Maxwellian collision model and its variable hard sphere surrogate
Authors: Rubinstein Robert
Published: August 2015

The variable hard sphere and related models have proven to be accurate and computationally convenient replacements for the inverse power law model of classical kinetic theory in direct simulation Monte Carlo calculations. We attempt to provide theoretical support for this remarkable success by comparing the relaxation rates in the linearized Boltzmann equation for the Maxwellian collision model with those of its variable hard sphere surrogate. The comparison demonstrates that the linearized collision operator with variable hard sphere interactions can accurately approximate the linearized collision operator with Maxwellian inverse power law interactions under well-defined and broadly applicable conditions. Extensions of the analysis to the general inverse power law model and to more realistic intermolecular potentials are briefly discussed.
Efficient treatment of induced dipoles
Authors: Simmonett Andrew C. , Pickard Frank C. , Shao Yihan , Cheatham Thomas E. , Brooks Bernard R.
Published: August 2015

Most existing treatments of induced dipoles in polarizable molecular mechanics force field calculations use either the self-consistent variational method, which is solved iteratively, or the “direct” approximation that is non-iterative as a result of neglecting coupling between induced dipoles. The variational method is usually implemented using assumptions that are only strictly valid under tight convergence of the induced dipoles, which can be computationally demanding to enforce. In this work, we discuss the nature of the errors that result from insufficient convergence and suggest a strategy that avoids such problems. Using perturbation theory to reintroduce the mutual coupling into the direct algorithm, we present a computationally efficient method that combines the precision of the direct approach with the accuracy of the variational approach. By analyzing the convergence of this perturbation series, we derive a simple extrapolation formula that delivers a very accurate approximation to the infinite order solution at the cost of only a few iterations. We refer to the new method as extrapolated perturbation theory. Finally, we draw connections to our previously published permanent multipole algorithm to develop an efficient implementation of the electric field and Thole terms and also derive some necessary, but not sufficient, criteria that force field parameters must obey.
Nonlinear frequency shift of electrostatic waves in general collisionless plasma: Unifying theory of fluid and kinetic nonlinearities
Authors: Liu Chang , Dodin Ilya Y.
Published: August 2015

The nonlinear frequency shift is derived in a transparent asymptotic form for intense Langmuir waves in general collisionless plasma. The formula describes both fluid and kinetic effects simultaneously. The fluid nonlinearity is expressed, for the first time, through the plasma dielectric function, and the kinetic nonlinearity accounts for both smooth distributions and trapped-particle beams. Various known limiting scalings are reproduced as special cases. The calculation avoids differential equations and can be extended straightforwardly to other nonlinear plasma waves.
Simulation of femtosecond two-dimensional electronic spectra of conical intersections
Authors: Krčmář Jindřich , Gelin Maxim F. , Domcke Wolfgang
Published: August 2015

We have simulated femtosecond two-dimensional (2D) electronic spectra for an excited-state conical intersection using the wave-function version of the equation-of-motion phase-matching approach. We show that 2D spectra at fixed values of the waiting time provide information on the structure of the vibronic eigenstates of the conical intersection, while the evolution of the spectra with the waiting time reveals predominantly ground-state wave-packet dynamics. The results show that 2D spectra of conical intersection systems differ significantly from those obtained for chromophores with well separated excited-state potential-energy surfaces. The spectral signatures which can be attributed to conical intersections are discussed.
Fractal and multifractal characteristics of swift heavy ion induced self-affine nanostructured BaF2 thin film surfaces
Authors: Yadav R. P. , Kumar Manvendra , Mittal A. K. , Pandey A. C.
Published: August 2015

Fractal and multifractal characteristics of self-affine surfaces of BaF2 thin films, deposited on crystalline Si ⟨1 1 1⟩ substrate at room temperature, were studied. Self-affine surfaces were prepared by irradiation of 120 MeV Ag9+ ions which modified the surface morphology at nanometer scale. The surface morphology of virgin thin film and those irradiated with different ion fluences are characterized by atomic force microscopy technique. The surface roughness (interface width) shows monotonic decrease with ion fluences, while the other parameters, such as lateral correlation length, roughness exponent, and fractal dimension, did not show either monotonic decrease or increase in nature. The self-affine nature of the films is further confirmed by autocorrelation function. The power spectral density of thin films surfaces exhibits inverse power law variation with spatial frequency, suggesting the existence of fractal component in surface morphology. The multifractal detrended fluctuation analysis based on the partition function approach is also performed on virgin and irradiated thin films. It is found that the partition function exhibits the power law behavior with the segment size. Moreover, it is also seen that the scaling exponents vary nonlinearly with the moment, thereby exhibiting the multifractal nature.
Giant microwave photo-conductance of a tunnel point contact with a bridged gate
Authors: Levin A. D. , Gusev G. M. , Kvon Z. D. , Bakarov A. K. , Savostianova N. A. , Mikhailov S. A. , Rodyakina E. E. , Latyshev A. V.
Published: August 2015

We study the microwave photo-response of a quantum point contact (QPC) formed on a GaAs/AlGaAs heterostructure with a high-electron-mobility two-dimensional electron gas. The QPCs are fabricated by two types of gates: a traditional split gate and a specially designed bridged gate. We observe a three orders of magnitude enhancement of the dark QPC conductance in the tunneling regime at the incident microwave power density of ∼10 mW/cm2. The response of the bridged-gate structure is more than ten times larger than that of the split-gate QPC. This giant effect and the difference between the two types of gates are explained by the influence of microwaves on the steady-state electron distribution function in the vicinity of the tunnel contact. Experimental results are in good quantitative agreement with theoretical calculations. The bridged-gate QPC can be used for the creation of highly sensitive detectors of electromagnetic radiation.
Incommensurate superstructure in heavily doped fullerene layer on Bi/Si(111) surface
Authors: Gruznev D. V. , Bondarenko L. V. , Tupchaya A. Y. , Matetskiy A. V. , Zotov A. V. , Saranin A. A.
Published: August 2015

Cs adsorption onto the C60-covered Si(111)-β-3×3-Bi reconstruction has been studied by means of scanning tunneling microscopy and photoelectron spectroscopy. Unexpected increase in apparent size of every second C60 molecule has been detected, hereupon the close packed molecular array almost doubles its periodicity. The change affects only the fullerenes that are in direct contact with the metal-induced reconstruction and takes no place already in the second layer. Photoelectron studies have revealed that this incommensurate “2 × 2” superstructure of a heavily doped C60 monolayer remains in an insulating state regardless of doping level.
Experimental investigation of quasiperiodic-chaotic-quasiperiodic-chaotic transition in a direct current magnetron sputtering plasma
Authors: Sabavath Gopi Kishan , Shaw Pankaj Kumar , Sekar Iyengar A. N. , Banerjee I. , Mahapatra S. K.
Published: August 2015

Floating potential fluctuations from a direct current magnetron sputtering plasma have been analysed using time series analysis techniques like phase space plots, power spectra, frequency bifurcation plot, etc. The system exhibits quasiperiodic-chaotic-quasiperiodic-chaotic transitions as the discharge voltage was increased. The transitions of the fluctuations, quantified using the largest Lyapunov exponent, have been corroborated by Hurst exponent and the Shannon entropy. The Shannon entropy is high for quasiperiodic and low for chaotic oscillations.
Algebraic techniques for diagonalization of a split quaternion matrix in split quaternionic mechanics
Authors: Jiang Tongsong , Jiang Ziwu , Zhang Zhaozhong
Published: August 2015

In the study of the relation between complexified classical and non-Hermitian quantum mechanics, physicists found that there are links to quaternionic and split quaternionic mechanics, and this leads to the possibility of employing algebraic techniques of split quaternions to tackle some problems in complexified classical and quantum mechanics. This paper, by means of real representation of a split quaternion matrix, studies the problem of diagonalization of a split quaternion matrix and gives algebraic techniques for diagonalization of split quaternion matrices in split quaternionic mechanics.
Fiber Bragg gratings in the radiation environment: Change under the influence of radiolytic hydrogen
Authors: Butov Oleg V. , Golant Konstantin M. , Shevtsov Igor' A. , Fedorov Artem N.
Published: August 2015

The change of the transmission spectra of fiber Bragg gratings written in the optical fibers, whose silica cores are doped with either germanium or nitrogen, is studied experimentally under the influence of gamma-radiation. The transmission spectra in the neighborhood of the resonance (Bragg) wavelengths were regularly recorded “in-situ” in the course of irradiation during 24 days. For this purpose, uncoated gratings were placed in a pool near the spent fuel rods of a nuclear reactor. The fibers with the gratings written in them were in immediate contact with water. The estimated total absorbed radiation dose of the fibers is approximately 5 MGy. Molecular hydrogen, which is produced by radiolysis of water and penetrates into the core of silica fiber, is found to interact with the defects of Ge-doped silica induced by gamma-radiation, thereby causing a strong impact on the parameters of the spectrum of the Bragg gratings. On the contrary, in the case of gratings inscribed in N-doped silica fibers, the hydrogen molecules interact with defects induced in the course of laser UV exposure during the grating writing only. The possible subsequent formation of additional defects in N-doped silica under the influence of gamma-radiation has no substantial impact on the transmission spectra of Bragg gratings, which remained stable. The obtained results suggest that a small amount of molecular hydrogen resided in the fiber core is the main source of radiation instability of Ge-doped fiber Bragg grating sensors in radiation environments. These hydrogen molecules can remain in the Bragg gratings, in particular, after the inscription process in the hydrogen-loaded fibers.
Self-organized target and spiral patterns through the “coffee ring” effect
Authors: Chen Yong-Jun , Suzuki Kosuke , Yoshikawa Kenichi
Published: August 2015

We studied the precipitation pattern of fullerene C60 nanocrystals generated through the evaporation of a confined liquid bridge. In contrast to the usual “coffee ring” pattern, both target and spiral patterns were observed. The characteristics of the pattern critically depended on the concentration of the solution, the temperature, and the level of vacuum. In addition, the morphology of the microscopic precipitates varied greatly as a function of these experimental parameters. This pattern formation can be interpreted as a two-step rhythmic nucleation/precipitation of fullerene crystals during receding motion of the contact line. Symmetric motion of the contact line produces a target pattern, and the propagation of distortion of the liquid interface caused by a disturbance generates a spiral pattern.
Direct observation of electric field induced pattern formation and particle aggregation in ferrofluids
Authors: Rajnak Michal , Petrenko Viktor I. , Avdeev Mikhail V. , Ivankov Olexandr I. , Feoktystov Artem , Dolnik Bystrik , Kurimsky Juraj , Kopcansky Peter , Timko Milan
Published: August 2015

Ferrofluids typically respond to magnetic fields and can be manipulated by external magnetic fields. Here, we report on formation of visually observable patterns in a diluted low-polarity ferrofluid exposed to external electric fields. This presents a specific type of ferrofluid structure driven by a combined effect of electrohydrodynamics and electrical body forces. The free charge and permittivity variation are considered to play a key role in the observed phenomenon. The corresponding changes in the ferrofluid structure have been found at nanoscale as well. By small-angle neutron scattering (SANS), we show that the magnetic nanoparticles aggregate in direct current (dc) electric field with a strong dependence on the field intensity. The anisotropic aggregates preferably orient in the direction of the applied electric field. Conducting SANS experiments with alternating current (ac) electric fields of various frequencies, we found a critical frequency triggering the aggregation process. Our experimental study could open future applications of ferrofluids based on insulating liquids.
A general ansatz for constructing quasi-diabatic states in electronically excited aggregated systems
Authors: Liu Wenlan , Lunkenheimer Bernd , Settels Volker , Engels Bernd , Fink Reinhold F. , Köhn Andreas
Published: August 2015

We present a general method for analyzing the character of singly excited states in terms of charge transfer (CT) and locally excited (LE) configurations. The analysis is formulated for configuration interaction singles (CIS) singly excited wave functions of aggregate systems. It also approximately works for the second-order approximate coupled cluster singles and doubles and the second-order algebraic-diagrammatic construction methods [CC2 and ADC(2)]. The analysis method not only generates a weight of each character for an excited state, but also allows to define the related quasi-diabatic states and corresponding coupling matrix elements. In the character analysis approach, we divide the target system into domains and use a modified Pipek-Mezey algorithm to localize the canonical MOs on each domain, respectively. The CIS wavefunction is then transformed into the localized basis, which allows us to partition the wavefunction into LE configurations within domains and CT configuration between pairs of different domains. Quasi-diabatic states are then obtained by mixing excited states subject to the condition of maximizing the weight of one single LE or CT configuration (localization in configuration space). Different aims of such a procedure are discussed, either the construction of pure LE and CT states for analysis purposes (by including a large number of excited states) or the construction of effective models for dynamics calculations (by including a restricted number of excited states). Applications are given to LE/CT mixing in π-stacked systems, charge-recombination matrix elements in a hetero-dimer, and excitonic couplings in multi-chromophoric systems.
Effective field enhancement factor and the influence of emitted space charge
Authors: Shiffler Donald A. , Tang Wilkin , Jensen Kevin L. , Golby Ken , LaCour Matthew , Petillo John J. , Harris John R.
Published: August 2015

Although Fowler and Nordheim developed the basics of field emission nearly one century ago with their introduction of the Fowler-Nordheim equation (FNE), the topic continues to attract research interest particularly with the development of new materials that have been proposed as field emitters. The first order analysis of experiments typically relies upon the FNE for at minimum a basic understand of the physical emission process and its parameters of emission. The three key parameters in the FNE are the work function, emission area, and field enhancement factor, all of which can be difficult to determine under experimental conditions. This paper focuses in particular, on the field enhancement factor β. It is generally understood that β provides an indication of the surface roughness or sharpness of a field emitter cathode. However, in this paper, we experimentally and computationally demonstrate that cathodes with highly similar surface morphologies can manifest quite different field enhancements solely through having different emission regions. This fact can cause one to re-interpret results in which a single sharp emitter is proposed to dominate the emission from a field emitting cathode.
Thermal weights for semiclassical vibrational response functions
Authors: Moberg Daniel R. , Alemi Mallory , Loring Roger F.
Published: August 2015

Semiclassical approximations to response functions can allow the calculation of linear and nonlinear spectroscopic observables from classical dynamics. Evaluating a canonical response function requires the related tasks of determining thermal weights for initial states and computing the dynamics of these states. A class of approximations for vibrational response functions employs classical trajectories at quantized values of action variables and represents the effects of the radiation-matter interaction by discontinuous transitions. Here, we evaluate choices for a thermal weight function which are consistent with this dynamical approximation. Weight functions associated with different semiclassical approximations are compared, and two forms are constructed which yield the correct linear response function for a harmonic potential at any temperature and are also correct for anharmonic potentials in the classical mechanical limit of high temperature. Approximations to the vibrational linear response function with quantized classical trajectories and proposed thermal weight functions are assessed for ensembles of one-dimensional anharmonic oscillators. This approach is shown to perform well for an anharmonic potential that is not locally harmonic over a temperature range encompassing the quantum limit of a two-level system and the limit of classical dynamics.
Spin currents injected electrically and thermally from highly spin polarized Co2MnSi
Authors: Pfeiffer Alexander , Hu Shaojie , Reeve Robert M. , Kronenberg Alexander , Jourdan Martin , Kimura Takashi , Kläui Mathias
Published: August 2015

We demonstrate the injection and detection of electrically and thermally generated spin currents probed in Co2MnSi/Cu lateral spin valves. Devices with different electrode separations are patterned to measure the non-local signal as a function of the electrode spacing and we determine a relatively high effective spin polarization α of Co2MnSi to be 0.63 and the spin diffusion length of Cu to be 500 nm at room temperature. The electrically generated non-local signal is measured as a function of temperature and a maximum signal is observed for a temperature of 80 K. The thermally generated non-local signal is measured as a function of current density and temperature in a second harmonic measurement detection scheme. We find different temperature dependences for the electrically and thermally generated non-local signals, which allows us to conclude that the temperature dependence of the signals is not just dominated by the transport in the Cu wire, but there is a crucial contribution from the different generation mechanisms, which has been largely disregarded till date.
Electrical characterization and transport model of n-gallium nitride nanowires
Authors: Benner O. , Blumberg C. , Arzi K. , Poloczek A. , Prost W. , Tegude F.-J.
Published: August 2015

The transport data of n-doped gallium-nitride self-assembled nanowires grown by metal-organic vapor-phase-epitaxy are determined. The wire diameter varies from 0.4 μm to 1.6 μm while the length was up to 50 μm. Optical lithography and lift-off were used to form Ti/Au multiple contacts to the nanowires for transmission line measurements. A specific contact resistance of ρC = 1.74 × 10−7 Ω cm2 and a nanowire resistivity of ρNW = 2.27 × 10−3 Ω cm could be determined. Electrical conductivity measurements were carried out and a model of the wire resistance as a function of the nanowire radius and the charge carrier concentration was developed. Using this model, the magnitude of the doping level of the n-GaN nanowires is determined. Based on this data, a dopant concentration of the GaN wires of about n = 1020 cm−3 has been investigated.
InAs/GaAs quantum dots on GaAs-on-V-grooved-Si substrate with high optical quality in the 1.3 μm band
Authors: Wan Yating , Li Qiang , Geng Yu , Shi Bei , Lau Kei May
Published: August 2015

We report self-assembled InAs/GaAs quantum dots (QDs) grown on a specially engineered GaAs-on-V-grooved-Si substrate by metal-organic vapor phase epitaxy. Recessed pockets formed on V-groove patterned Si (001) substrates were used to prevent most of the hetero-interfacial stacking faults from extending into the upper QD active region. 1.3 μm room temperature emission from high-density (5.6 × 1010 cm−2) QDs has been obtained, with a narrow full-width-at-half-maximum of 29 meV. Optical quality of the QDs was found to be better than those grown on conventional planar offcut Si templates, as indicated by temperature-dependent photoluminescence analysis. Results suggest great potential to integrate QD lasers on a Si complementary-metal-oxide-semiconductor compatible platform using such GaAs on Si templates.
Hydromagnetic flow of third grade nanofluid with viscous dissipation and flux conditions
Authors: Hussain T. , Shehzad S. A. , Hayat T. , Alsaedi A.
Published: August 2015

This article investigates the magnetohydrodynamic flow of third grade nanofluid with thermophoresis and Brownian motion effects. Energy equation is considered in the presence of thermal radiation and viscous dissipation. Rosseland’s approximation is employed for thermal radiation. The heat and concentration flux conditions are taken into account. The governing nonlinear mathematical expressions of velocity, temperature and concentration are converted into dimensionless expressions via transformations. Series solutions of the dimensionless velocity, temperature and concentration are developed. Convergence of the constructed solutions is checked out both graphically and numerically. Effects of interesting physical parameters on the temperature and concentration are plotted and discussed in detail. Numerical values of skin-friction coefficient are computed for the hydrodynamic and hydromagnetic flow cases.
Population structure of the invasive species Leucaena leucocephala (Fabaceae) in a seasonal semi-deciduous forest, southern Brazil
Authors: Costa Janete T. , Fonseca Inês C. B. , Bianchini Edmilson
Published: August 2015

Biological invasions are one of the great threats of our time, and the accumulation of knowledge of invasive species is essential for invasive species management. In this study, aspects of the population ecology of Leucaena leucocephala (Lam) de Wit were investigated in a seasonal semi-deciduous forest remnant (23°15ʹ28ʹʹS, 51°01ʹ52ʹʹW – centre of the remnant) in Southern Brazil to evaluate whether the species is invading the remnant. In the first season, 1974 individuals, distributed heterogeneously in the remnant, were sampled. The population height structure fitted a negative exponential growth curve function (r2 = 0.9), indicating that the population was persisting through recruitment. The population also had a grouped spatial pattern and high recruitment rate. The species invaded the disturbed areas of the remnant. Gradual eradication is recommended for L. leucocephala for the remnant.
Graphene decorated microelectrodes for simultaneous detection of ascorbic, dopamine, and folic acids by means of chemical vapor deposition
Authors: Namdar N , Hassanpour Amiri M , Dehghan Nayeri F , Gholizadeh A , Mohajerzadeh S
Published: August 2015

In this paper, high quality and large area graphene layers were synthesized using thermal chemical vapour deposition on copper foil substrates. We use graphene incorporated electrodes to measure simultaneously ascorbic acid, dopamine and folic acid. Cyclic voltammetry and differential pulse voltammetry methods were used to evaluate electrochemical behaviour of the grown graphene layers. The graphene-modified electrode shows large electrochemical potential difference compared to bare gold electrodes with higher current responses. Also our fabricated electrodes configuration can be used easily for microfluidic analysis.
Inducible Expression of Agrobacterium Virulence Gene VirE2 for Stringent Regulation of T-DNA Transfer in Plant Transient Expression Systems
Authors: Denkovskienė Erna , Paškevičius Šarūnas , Werner Stefan , Gleba Yuri , Ražanskienė Aušra
Published: August 2015

Agrotransfection with viral vectors is an effective solution for the transient production of valuable proteins in plants grown in contained facilities. Transfection methods suitable for field applications are desirable for the production of high-volume products and for the transient molecular reprogramming of plants. The use of genetically modified (GM) Agrobacterium strains for plant transfections faces substantial biosafety issues. The environmental biosafety of GM Agrobacterium strains could be improved by regulating their T-DNA transfer via chemically inducible expression of virE2, one of the essential Agrobacterium virulence genes. In order to identify strong and stringently regulated promoters in Agrobacterium strains, we evaluated isopropyl-β-d-thiogalactoside–inducible promoters Plac, Ptac, PT7/lacO, and PT5/lacOlacO and cumic acid–inducible promoters PlacUV5/CuO, Ptac/CuO, PT5/CuO, and PvirE/CuO. Nicotiana benthamiana plants were transfected with a virE2-deficient A. tumefaciens strain containing transient expression vectors harboring inducible virE2 expression cassettes and containing a marker green fluorescent protein (GFP) gene in their T-DNA region. Evaluation of T-DNA transfer was achieved by counting GFP expression foci on plant leaves. The virE2 expression from cumic acid–induced promoters resulted in 47 to 72% of wild-type T-DNA transfer. Here, we present efficient and tightly regulated promoters for gene expression in A. tumefaciens and a novel approach to address environmental biosafety concerns in agrobiotechnology.
Use and Perceived Impact of the County Health Rankings Report in Florida and North Carolina
Authors: Winterbauer Nancy L. , Rafferty Ann P. , Tucker Ashley , Jones Katherine , Tucker-McLaughlin Mary
Published: August 2015

Objective:

Examine overall level of and variation in local health department (LHD) use and perceived impact of the County Health Rankings report (Rankings) in Florida (2010, 2011) and North Carolina (2010-2012, 2013).

Design:

Two cross-sectional surveys among LHDs.

Participants:

Local health directors and relevant staff.

Main Outcome Measures:

Use of the Rankings was measured by asking respondents if their LHD had used the Rankings in any of 10 ways and through assessment of community engagement. Perceived impact was measured by amount of attention the Rankings received from various stakeholders and whether they had already produced or would likely produce any of 7 possible results.

Results:

Overall, LHDs used the Rankings most often to educate staff in Florida (78%) and North Carolina (56%). Engagement with community groups around the Rankings was variable. Media engagement, through press releases (41%; 40%) or interviews (51%; 36%) in Florida and North Carolina, was moderate. Florida LHDs used the Rankings in more ways and significantly more frequently than North Carolina LHDs. There were few significant differences in perceived impact by state. At least a moderate amount of attention was received from media in Florida (52%) and North Carolina (46%). Twenty-percent of LHDs reported the Rankings received at least moderate attention from the general public in both states and 38% (Florida) and 33% (North Carolina) from policy makers. Tangible benefits to communities from the Rankings, such as having already influenced adoption of new policies, were modest in Florida (3%) and North Carolina (11%).

Conclusions:

Results suggest that tangible benefits to communities from use of the Rankings have yet to be fully realized but are encouraging. More effective media engagement could produce the community awareness necessary to maximize the Rankings' potential to mobilize communities for health improvement. State variation in Rankings use suggests that more support to LHDs may be helpful.
Undibacterium aquatile sp. nov., isolated from a waterfall
Authors: Du Juan , Akter Shahina , Won KyungHwa , Singh Hina , Shik Yin Chang , Kook MooChang , Yi Tae-Hoo
Published: August 2015

A Gram-stain-negative, aerobic, motile and rod-shaped strain, THG-DN7.3T, was isolated from a waterfall. Strain THG-DN7.3T grew well at 18–28 °C and at pH 6.0–7.5 on Reasoner's 2A agar. Based on 16S rRNA gene sequence comparisons, strain THG-DN7.3T was most closely related to Undibacterium jejuense JS4-4T (97.3 % 16S rRNA gene sequence similarity) and Undibacterium seohonense SHS5-24T (96.5 %). The G+C content of the genomic DNA was 57.4 mol%. The mean DNA–DNA relatedness of strain THG-DN7.3T with U. jejuense KACC 12607T was 40 ± 1 % (reciprocal 50 ± 2.1 %). The major cellular fatty acids of strain THG-DN7.3T were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) (47.4 %), C16 : 0 (30.4 %), summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c) (6.8 %) and C12 : 0 (6.2 %). The predominant isoprenoid quinone was ubiquinone-8. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The results of the DNA–DNA hybridization and genotypic analysis, in combination with chemotaxonomic and physiological data, demonstrated that strain THG-DN7.3T represents a novel species of the genus Undibacterium, for which the name Undibacterium aquatile sp. nov. is proposed. The type strain is THG-DN7.3T ( = KCTC 42243T = CCTCC AB 2015119T).
Statistical Inference of a Convergent Antibody Repertoire Response to Influenza Vaccine
Authors: Strauli Nicolas , Hernandez Ryan
Published: August 2015

Background

Vaccines dramatically affect an individual’s adaptive immune system, and thus provide an excellent means to study human immunity. Upon vaccination, the B cells that express antibodies (Abs) that happen to bind the vaccine are stimulated to proliferate and undergo mutagenesis at their Ab locus. This process may alter the composition of B cell lineages within an individual, which are known collectively as the antibody repertoire (AbR). Antibodies are also highly expressed in whole blood, potentially enabling unbiased RNA sequencing technologies to query this diversity. Less is known about the diversity of AbR responses across individuals to a given vaccine and if individuals tend to yield a similar response to the same antigenic stimulus.

Methods

Here we implement a bioinformatic pipeline that extracts the AbR information from a time-series RNA-seq dataset of 5 patients who were administered a seasonal trivalent influenza vaccine (TIV). We harness the detailed time-series nature of this dataset and use methods based in functional data analysis (FDA) to identify the B cell lineages that respond to the vaccine. We then design and implement rigorous statistical tests in order to ask whether or not these patients exhibit a convergent AbR response to the same TIV.

Results

We find that high-resolution time-series data can be used to help identify the Ab lineages that respond to an antigenic stimulus, and that this response can exhibit a convergent nature across patients inoculated with the same vaccine. However, correlations in AbR diversity among individuals prior to inoculation can confound inference of a convergent signal unless it is taken into account.

Conclusions

We developed a framework to identify the elements of an AbR that respond to an antigen. This information could be used to understand the diversity of different immune responses in different individuals, as well as to gauge the effectiveness of the immune response to a given stimulus within an individual. We also present a framework for testing a convergent hypothesis between AbRs; a hypothesis that is more difficult to test than previously appreciated. Our discovery of a convergent signal suggests that similar epitopes do select for antibodies with similar sequence characteristics.