bluuebunny/crossref_metadata_2025 huggingface dataset:
Fast evaluation of solid harmonic Gaussian integrals for local resolution-of-the-identity methods and range-separated hybrid functionals
Authors: Golze Dorothea , Benedikter Niels , Iannuzzi Marcella , Wilhelm Jan , Hutter Jürg
Published: January 2017

An integral scheme for the efficient evaluation of two-center integrals over contracted solid harmonic Gaussian functions is presented. Integral expressions are derived for local operators that depend on the position vector of one of the two Gaussian centers. These expressions are then used to derive the formula for three-index overlap integrals where two of the three Gaussians are located at the same center. The efficient evaluation of the latter is essential for local resolution-of-the-identity techniques that employ an overlap metric. We compare the performance of our integral scheme to the widely used Cartesian Gaussian-based method of Obara and Saika (OS). Non-local interaction potentials such as standard Coulomb, modified Coulomb, and Gaussian-type operators, which occur in range-separated hybrid functionals, are also included in the performance tests. The speed-up with respect to the OS scheme is up to three orders of magnitude for both integrals and their derivatives. In particular, our method is increasingly efficient for large angular momenta and highly contracted basis sets.
Migration of a surfactant-laden droplet in non-isothermal Poiseuille flow
Authors: Das Sayan , Mandal Shubhadeep , Som S. K. , Chakraborty Suman
Published: January 2017

The motion of a surfactant-laden viscous droplet in the presence of non-isothermal Poiseuille flow is studied analytically and numerically. Specifically, the focus of the present study is on the role of interfacial Marangoni stress generated due to imposed temperature gradient and non-uniform distribution of bulk-insoluble surfactants towards dictating the velocity and direction of motion of the droplet when the background flow is Poiseuille. Assuming the thermal convection and fluid inertia to be negligible, we obtain the explicit expression for steady velocity of a non-deformable spherical droplet when the droplet is located at the centerline of the imposed unbounded Poiseuille flow and encountering a linearly varying temperature field. Under these assumptions, the interfacial transport of surfactants is governed by the surface Péclet number which represents the relative strength of the advective transport of surfactant molecules over the diffusive transport. We obtain analytical solution for small and large values of the surface Péclet number. Analytical solution is also obtained for the case in which the surface Péclet number is of order unity by considering small surfactant Marangoni number which represents the relative strength of the surfactant-induced Marangoni stress over the viscous stress. For an arbitrary surface Péclet number, a numerical solution of the surfactant transport equation is performed using an iterative method which compares well with the analytical solutions. Depending on the direction of temperature gradient with respect to the imposed Poiseuille flow, the surfactant-induced Marangoni stress affects the droplet velocity significantly. When the imposed temperature increases in the direction of imposed Poiseuille flow, surfactants retard the droplet motion as compared with a surfactant-free droplet. However, when the imposed temperature decreases in the direction of imposed Poiseuille flow, the presence of surfactants may increase or decrease the magnitude of droplet velocity depending on the relevant governing parameters. Importantly, for particular values of governing parameters, we observe change in the direction of droplet motion due to the presence of surfactants, which may bear significant consequences in the design of droplet based microfluidic systems.
AC transport and full-counting statistics of molecular junctions in the weak electron-vibration coupling regime
Authors: Ueda A. , Utsumi Y. , Tokura Y. , Entin-Wohlman O. , Aharony A.
Published: January 2017

The coupling of the charge carriers passing through a molecule bridging two bulky conductors with local vibrational modes of the molecule gives rise to distinct features in the electronic transport properties on one hand and to nonequilibrium features in the vibrations’ properties, e.g., their population, on the other. Here we explore theoretically a generic model for a molecular junction biased by an arbitrary dc voltage in the weak-coupling regime. We succinctly summarize parts of our past work related to the signature of the electron-vibration interaction on the full-counting statistics of the current fluctuations (i.e., the cumulant generating-function of the current correlations). In addition, we provide a novel account of the response to an ac field exerted on the junction (on top of the dc bias voltage); in particular, we study the nonequilibrium distribution and the displacement fluctuations of the vibrational modes. Remarkably, we find a behavior pattern that cannot be accounted for by classical forced oscillations. The calculations use the technique of nonequilibrium Green’s functions and treat the electron-vibration coupling in perturbation theory, within the random-phase approximation when required.
Structural differences between capped GaSb nanostructures grown by Stranski-Krastanov and droplet epitaxy growth modes
Authors: DeJarld Matt , Yan Lifan , Luengo-Kovac Marta , Sih Vanessa , Millunchick Joanna
Published: January 2017

Droplet epitaxy (DE) has emerged as an alternative to Stranski-Krastanov (SK) as a method for epitaxial nanostructure formation. We find significant structural differences of similar sized nanostructures embedded in GaAs between the two methods. Atomic force microscopy and atom probe tomography measurements reveal that uncapped and capped SK structures resemble each other. However, the DE nanostructures appear as rings topographically but are quantum dots compositionally. A GaSb wetting layer is present regardless of the growth method and shares a nearly identical Sb concentration profile. DE nanostructures are shown to have a lower Sb concentration, and transmission electron microscopy measurements reveal that they produce less strain on the capping layer. Despite significant structural differences, SK and DE nanostructures exhibit the same photoluminescence response, suggesting that the emission is from a shared feature such as the wetting layer, rather than the nanostructures.
Scalar mixing and strain dynamics methodologies for PIV/LIF measurements of vortex ring flows
Authors: Bouremel Yann , Ducci Andrea
Published: January 2017

Fluid mixing operations are central to possibly all chemical, petrochemical, and pharmaceutical industries either being related to biphasic blending in polymerisation processes, cell suspension for biopharmaceuticals production, and fractionation of complex oil mixtures. This work aims at providing a fundamental understanding of the mixing and stretching dynamics occurring in a reactor in the presence of a vortical structure, and the vortex ring was selected as a flow paradigm of vortices commonly encountered in stirred and shaken reactors in laminar flow conditions. High resolution laser induced fluorescence and particle imaging velocimetry measurements were carried out to fully resolve the flow dissipative scales and provide a complete data set to fully assess macro- and micro-mixing characteristics. The analysis builds upon the Lamb-Oseen vortex work of Meunier and Villermaux [“How vortices mix,” J. Fluid Mech. 476, 213–222 (2003)] and the engulfment model of Baldyga and Bourne [“Simplification of micromixing calculations. I. Derivation and application of new model,” Chem. Eng. J. 42, 83–92 (1989); “Simplification of micromixing calculations. II. New applications,” ibid. 42, 93–101 (1989)] which are valid for diffusion-free conditions, and a comparison is made between three methodologies to assess mixing characteristics. The first method is commonly used in macro-mixing studies and is based on a control area analysis by estimating the variation in time of the concentration standard deviation, while the other two are formulated to provide an insight into local segregation dynamics, by either using an iso-concentration approach or an iso-concentration gradient approach to take into account diffusion.
Refraction of cylindrical converging shock wave at an air/helium gaseous interface
Authors: Zhai Zhigang , Li Wei , Si Ting , Luo Xisheng , Yang Jiming , Lu Xiyun
Published: January 2017

Refraction of a cylindrical converging shock wave at an inclined air/helium interface is investigated. Experimentally, based on the shock dynamics theory, a special wall profile is designed to generate a perfectly cylindrical converging shock wave. A soap film technique is developed to form an inclined discontinuous air/helium interface, and high-speed schlieren photography is adopted to capture the flow. Numerical simulations are also performed to compare with the experimental counterparts and to show details of refraction. In this work, two initial incident angles (45° and 60°) are considered. As the incident shock converges inward, the shock intensity increases while the incident angle decreases, causing possible transitions among the wave patterns. For the case of 45°, an irregular refraction of free precursor refraction (FPR) first occurs and gradually transits into regular refraction, while for the case of 60°, various irregular refractions of twin von Neumann refraction (TNR), twin regular refraction (TRR), free precursor von Neumann refraction (FNR), and FPR occur in sequence. The transition sequences do not belong to any groups described in the planar counterpart, indicating that the classification of the refraction phenomenon in the planar case is not exhaustive or cannot be applied to the converging case. It is also the first time to observe the transition from FNR to FPR, providing an experimental evidence for the previous numerical results. It is deemed that the difference between the velocities of the incident and transmitted shocks propagating along the interface is the primary factor that induces the transitions among wave patterns.
An enhanced tokamak startup model
Authors: Goswami Rajiv , Artaud Jean-François ,   ADITYA Team
Published: January 2017

The startup of tokamaks has been examined in the past in varying degree of detail. This phase typically involves the burnthrough of impurities and the subsequent rampup of plasma current. A zero-dimensional (0D) model is most widely used where the time evolution of volume averaged quantities determines the detailed balance between the input and loss of particle and power. But, being a 0D setup, these studies do not take into consideration the co-evolution of plasma size and shape, and instead assume an unchanging minor and major radius. However, it is known that the plasma position and its minor radius can change appreciably as the plasma evolves in time to fill in the entire available volume. In this paper, an enhanced model for the tokamak startup is introduced, which for the first time takes into account the evolution of plasma geometry during this brief but highly dynamic period by including realistic one-dimensional (1D) effects within the broad 0D framework. In addition the effect of runaway electrons (REs) has also been incorporated. The paper demonstrates that the inclusion of plasma cross section evolution in conjunction with REs plays an important role in the formation and development of tokamak startup. The model is benchmarked against experimental results from ADITYA tokamak.
Simulation of high SNR photodetector with L-C coupling and transimpedance amplifier circuit and its verification
Authors: Wang Shaofeng , Xiang Xiao , Zhou Conghua , Zhai Yiwei , Quan Runai , Wang Mengmeng , Hou Feiyan , Zhang Shougang , Dong Ruifang , Liu Tao
Published: January 2017

In this paper, a model for simulating the optical response and noise performances of photodetectors with L-C coupling and transimpedance amplification circuit is presented. To verify the simulation, two kinds of photodetectors, which are based on the same printed-circuit-board (PCB) designing and PIN photodiode but different operational amplifiers, are developed and experimentally investigated. Through the comparisons between the numerical simulation results and the experimentally obtained data, excellent agreements are achieved, which show that the model provides a highly efficient guide for the development of a high signal to noise ratio photodetector. Furthermore, the parasite capacitances on the developed PCB, which are always hardly measured but play a non-negligible influence on the photodetectors’ performances, are estimated.
A new time and space resolved transmission spectrometer for research in inertial confinement fusion and radiation source development
Authors: Knapp P. F. , Ball C. , Austin K. , Hansen S. B. , Kernaghan M. D. , Lake P. W. , Ampleford D. J. , McPherson L. A. , Sandoval D. , Gard P. , Wu M. , Bourdon C. , Rochau G. A. , McBride R. D. , Sinars D. B.
Published: January 2017

We describe the design and function of a new time and space resolved x-ray spectrometer for use in Z-pinch inertial confinement fusion and radiation source development experiments. The spectrometer is designed to measure x-rays in the range of 0.5–1.5 Å (8–25 keV) with a spectral resolution λ/Δλ ∼ 400. The purpose of this spectrometer is to measure the time- and one-dimensional space-dependent electron temperature and density during stagnation. These relatively high photon energies are required to escape the dense plasma created at stagnation and to obtain sensitivity to electron temperatures ≳3 keV. The spectrometer is of the Cauchois type, employing a large 30 × 36 mm2, transmissive quartz optic for which a novel solid beryllium holder was designed. The performance of the crystal was verified using offline tests, and the integrated system was tested using experiments on the Z pulsed power accelerator.
Local spin dynamics of iron oxide magnetic nanoparticles dispersed in different solvents with variable size and shape: A 1H NMR study
Authors: Basini M. , Orlando T. , Arosio P. , Casula M. F. , Espa D. , Murgia S. , Sangregorio C. , Innocenti C. , Lascialfari A.
Published: January 2017

Colloidal magnetic nanoparticles (MNPs) based on a nearly monodisperse iron oxide core and capped by oleic acid have been used as model systems for investigating the superparamagnetic spin dynamics by means of magnetometry measurements and nuclear magnetic resonance (1H NMR) relaxometry. The key magnetic properties (saturation magnetization, coercive field, and frequency dependent “blocking” temperature) of MNPs with different core size (3.5 nm, 8.5 nm, and 17.5 nm), shape (spherical and cubic), and dispersant (hexane and water-based formulation) have been determined. 1H NMR dispersion profiles obtained by measuring the r1 (longitudinal) and r2 (transverse) nuclear relaxivities in the frequency range 0.01–60 MHz confirmed that in all samples the physical mechanisms that drive the nuclear relaxation are the Néel reversal at low temperature and the Curie relaxation at high frequency. The magnetization reversal time at room temperature extracted from the fitting of NMR data falls in the typical range of superparamagnetic systems (10−9-10−10 s). Furthermore, from the distance of minimum approach we could conclude that water molecules do not arrive in close vicinity of the magnetic core. Our findings contribute to elucidate the local spin dynamics mechanisms in colloidal superparamagnetic nanoparticles which are useful in biomedical application as, e.g., contrast agents for magnetic resonance imaging.
The unconventional doping in YBa2Cu3O7−x/La0.7Ca0.3MnO3 heterostructures by termination control
Authors: Tra V. T. , Huang R. , Gao X. , Chen Y.-J. , Liu Y. T. , Kuo W. C. , Chin Y. Y. , Lin H. J. , Chen J. M. , Lee J. M. , Lee J. F. , Shi P. S. , Jiang M. G. , Duan C. G. , Juang J. Y. , Chen C. T. , Jeng H. T. , He Q. , Chuang Y.-D. , Lin J.-Y. , Chu Y.-H.
Published: January 2017

In strongly correlated oxides, heterostructures provide a powerful route to manipulate the charge, spin, orbital, and lattice degrees of freedom to create distinctive functionalities. In this work, we have achieved atomically precise interface control in YBa2Cu3O7−x/La0.7Ca0.3MnO3 (YBCO/LCMO) heterostructures and find a hidden effective doping. This mechanism is responsible for higher Tc in the sample with the MnO2-terminated interface than in that with the La0.7Ca0.3O-terminated interface. The MnO2-terminated sample also shows a larger magnetic moment of Mn together with a lower valence state. For more than a decade, the control of Tc in these heterostructures prior to this work has been solely via the variation of YBCO or LCMO thickness. This work hints at an alternative way of exploiting and exploring the interactions between superconductivity and magnetism in this system.
A quantitative strain analysis of a flexible single-crystalline silicon membrane
Authors: Bong Jae Hoon , Kim Cheolgyu , Hwang Wan Sik , Kim Taek-Soo , Cho Byung Jin
Published: January 2017

This study presents a quantitative strain analysis of a single-crystal Si membrane for high performance flexible devices. Advanced thinning and transfer methods were used to make flexible single-crystal Si devices. Two Si membrane strain gauges, each with a different stack, were fabricated on a polydimethylsiloxane/polyimide film using a silicon-on-insulator wafer. One gauge contains a 10-μm-thick handling Si layer, whereas the handling Si layer was completely removed for the other case. Although the Si membrane with the 10-μm-thick handling Si layer is flexible, the strain applied to the active Si layer (0.127%) is three times higher than the strain applied to the Si membrane without the handling Si layer (0.037%) at a bending radius of 5 mm. This leads to the more reliable electrical and mechanical performance of the device fabricated on the Si membrane without the handling Si layer. The experimental results were verified through a finite element method simulation and analytical modeling. The quantitative strain analyses for flexible devices suggested here can expedite the realization of high performance flexible electronics using a single crystal silicon active layer.
Bethe-Salpeter study of cationic dyes: Comparisons with ADC(2) and TD-DFT
Authors: Azarias Cloé , Duchemin Ivan , Blase Xavier , Jacquemin Denis
Published: January 2017

We present a theoretical investigation of the excited-state properties of a large series of structurally diverse arylcarbonium derivatives that are known to be challenging for theoretical models. More specifically, we compare the pros and cons of TD-DFT (TD-M06-2X), ADC(2), and BSE/GW approaches for a large panel of compounds, using two different solvent models. Both 0-0 and vertical transition energies are considered and compared to the experimental values. All approaches reasonably reproduce the auxochromic and acidochromic shifts, although in most cases both TD-DFT and BSE/GW return larger correlation with experimental values than ADC(2) for these shifts. In contrast, the absolute transition energies obtained with ADC(2) tend to be closer to the measurements, TD-DFT using the M06-2X functional largely overestimating the experimental references (by ca. 0.5 eV), and BSE/GW providing intermediate values. In addition, we show that the selected solvent model has a significant impact on the results, the corrected linear-response approach providing larger transition energies than its linear-response counterpart.
Dew point fast measurement in organic vapor mixtures using quartz resonant sensor
Authors: Nie Jing , Liu Jia , Meng Xiaofeng
Published: January 2017

A fast dew point sensor has been developed for organic vapor mixtures by using the quartz crystal with sensitive circuits. The sensor consists of the quartz crystal and a cooler device. Proactive approach is taken to produce condensation on the surface of the quartz crystal, and it will lead to a change in electrical features of the quartz crystal. The cessation of oscillation was measured because this phenomenon is caused by dew condensation. Such a phenomenon can be used to detect the dew point. This method exploits the high sensitivity of the quartz crystal but without frequency measurement and also retains the stability of the resonant circuit. It is strongly anti-interfered. Its performance was evaluated with acetone–methanol mixtures under different pressures. The results were compared with the dew points predicted from the universal quasi-chemical equation to evaluate the performance of the proposed sensor. Though the maximum deviations of the sensor are less than 1.1 °C, it still has a fast response time with a recovery time of less than 10 s, providing an excellent dehumidifying performance.
Parametric decay of a parallel propagating monochromatic whistler wave: Particle-in-cell simulations
Authors: Ke Yangguang , Gao Xinliang , Lu Quanming , Wang Shui
Published: January 2017

In this paper, by using one-dimensional (1-D) particle-in-cell simulations, we investigate the parametric decay of a parallel propagating monochromatic whistler wave with various wave frequencies and amplitudes. The pump whistler wave can decay into a backscattered daughter whistler wave and an ion acoustic wave, and the decay instability grows more rapidly with the increase of the frequency or amplitude. When the frequency or amplitude is sufficiently large, a multiple decay process may occur, where the daughter whistler wave undergoes a secondary decay into an ion acoustic wave and a forward propagating whistler wave. We also find that during the parametric decay a considerable part of protons can be accelerated along the background magnetic field by the enhanced ion acoustic wave through the Landau resonance. The implication of the parametric decay to the evolution of whistler waves in Earth's magnetosphere is also discussed in the paper.
Proton acceleration from magnetized overdense plasmas
Authors: Kuri Deep Kumar , Das Nilakshi , Patel Kartik
Published: January 2017

Proton acceleration by an ultraintense short pulse circularly polarized laser from an overdense three dimensional (3D) particle-in-cell (PIC) 3D-PIC simulations. The axial magnetic field modifies the dielectric constant of the plasma, which causes a difference in the behaviour of ponderomotive force in case of left and right circularly polarized laser pulse. When the laser is right circularly polarized, the ponderomotive force gets enhanced due to cyclotron effects generating high energetic electrons, which, on reaching the target rear side accelerates the protons via target normal sheath acceleration process. On the other hand, in case of left circular polarization, the effects get reversed causing a suppression of the ponderomotive force at a short distance and lead towards a rise in the radiation pressure, which results in the effective formation of laser piston. Thus, the axial magnetic field enhances the effect of radiation pressure in case of left circularly polarized laser resulting in the generation of high energetic protons at the target front side. The transverse motion of protons get reduced as they gyrate around the axial magnetic field which increases the beam collimation to some extent. The optimum thickness of the overdense plasma target is found to be increased in the presence of an axial magnetic field.
Carrier transport performance of Cd0.9Zn0.1Te detector by direct current photoconductive technology
Authors: Ling Yunpeng , Min Jiahua , Liang Xiaoyan , Zhang Jijun , Yang Liuqing , Zhang Ying , Li Ming , Liu Zhaoxin , Wang Linjun
Published: January 2017

In this paper, based on the derivation of the Hecht model and Many model, we establish a new theoretical model and deduce its mathematical equation by considering an even-distributed charged center of certain concentration under constant illumination. This model helps us deeply understand the carrier transport performance of Cd0.9Zn0.1Te (CZT) under various illuminations and non-uniform distribution of the internal electric field in CZT. In our research, direct current photoconductive technology (DCPT) is applied to assess the electrical transport properties of carriers in CZT crystals, which is verified by room temperature Am-241 alpha-particle responses and charge collection efficiency test. The mobility-lifetime product (μτ) for carriers is extracted from fitting the Hecht model by DCPT for CZT radiated from the cathode and anode by a constant laser, respectively. Moreover, the carrier transport properties of CZT under various light intensities and during a wide range of temperatures are also taken and analyzed in detail, which enable us to develop the best performance of CZT. In addition, we figure out a method for estimating μeτe and μhτh  on different positions of CZT wafer on the basis of the pixel detector that collects single polarity charge, and several corrective actions have improved the accuracy of the measurement.
Controllable piezoelectricity of Pb(Zr0.2Ti0.8)O3 film via in situ misfit strain
Authors: Lee Hyeon Jun , Guo Er-Jia , Kwak Jeong Hun , Hwang Seung Hyun , Dörr Kathrin , Lee Jun Hee , Young Jo Ji
Published: January 2017

The tetragonality (c/a) of a PbZr0.2Ti0.8O3 (PZT) thin film on La0.7Sr0.3MnO3/ 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 (PMN-PT) substrates was controlled by applying an electric field on the PMN-PT substrate. The piezoelectric response of the PZT thin film under various biaxial strains was observed using time-resolved micro X-ray diffraction. The longitudinal piezoelectric coefficient (d33) was reduced from 29.5 to 14.9 pm/V when the c/a ratio of the PZT film slightly changed from 1.051 to 1.056. Our results demonstrate that the tetragonality of the PZT thin film plays a critical role in determining d33, and in situ strain engineering using electromechanical substrate is useful in excluding the extrinsic effect resulting from the variation in the film thickness or the interface between substrate.
Polarization of stacking fault related luminescence in GaN nanorods
Authors: Pozina G. , Forsberg M. , Serban E. A. , Hsiao C.-L. , Junaid M. , Birch J. , Kaliteevski M. A.
Published: January 2017

Linear polarization properties of light emission are presented for GaN nanorods (NRs) grown along [0001] direction on Si(111) substrates by direct-current magnetron sputter epitaxy. The near band gap photoluminescence (PL) measured at low temperature for a single NR demonstrated an excitonic line at ∼3.48 eV and the stacking faults (SFs) related transition at ∼3.43 eV. The SF related emission is linear polarized in direction perpendicular to the NR growth axis in contrast to a non-polarized excitonic PL. The results are explained in the frame of the model describing basal plane SFs as polymorphic heterostructure of type II, where anisotropy of chemical bonds at the interfaces between zinc blende and wurtzite GaN subjected to in-built electric field is responsible for linear polarization parallel to the interface planes.
Phonon frequencies of a highly strained AlN layer coherently grown on 6H-SiC (0001)
Authors: Kaneko M. , Kimoto T. , Suda J.
Published: January 2017

Phonon frequencies of a high-quality AlN layer coherently grown on a 6H-SiC (0001) substrate are investigated by Raman scattering. Owing to the largest strain in our coherent AlN layer among heteroepitaxially grown AlN layers ever reported, phonon frequencies of the E2 (low), E2 (high), and A1 (LO) modes are considerably shifted to 244.5 (−3.3, compared with bulk AlN), 672.1 (+16.3), and 899 (+11)cm−1, respectively. Full widths at half maximum of the phonon modes in the coherent AlN are almost equal to those of high-quality bulk AlN, clearly indicating its high crystalline quality and uniform strain. We discuss accuracy of phonon deformation potentials reported by several other groups thorough comparing our experimental results.
Optimising finishing pig delivery weight: participatory decision problem analysis
Authors: Leen F. , Van den Broeke A. , Aluwé M. , Lauwers L. , Millet S. , Van Meensel J.
Published: January 2017

The seemingly straightforward question of optimal pig delivery weight is more complex than meets the eye. Despite abundant research insights, the industry continues to request additional applied scientific decision support on the delivery weight problem. The current objective is to investigate whether and how the complex decision of delivery weight can be reshaped (reframed) into a more tangible and comprehensible system of factors that matter for making the right decision. We used a participatory decision problem analysis, which resulted in modelling blueprints that incorporate factors prioritised by stakeholders for determining optimal delivery weights. How to efficiently organise such a ‘problem reframing process’ is case-specific: it depends on the objective, the initial problem understanding by the stakeholders, and their learning potential. Efficient co-learning is a prerequisite for successful participatory problem analysis. Our study reveals that the first step in such a process of ‘problem reframing’ should therefore be to answer the question of how to effectively organise co-learning among stakeholders and researchers, instead of starting with a correct and detailed representation of the problem. Useful guidelines for participatory problem reframing processes are (1) providing sufficient participatory learning steps, (2) having few and clearly defined objectives per learning step, (3) providing adapted learning tools per step, (4) establishing a common language and (5) deliberately choosing stakeholders based on prior knowledge of the problem or its context, potential motivation or incentives to be part of the participatory process step and potential role in up-scaling the co-learning process to a larger group of beneficiaries.
Methionine supplementation of low-protein diet and subsequent feeding of low-energy diet on the performance and blood chemical profile of broiler chickens
Authors: Jariyahatthakij P. , Chomtee B. , Poeikhampha T. , Loongyai W. , Bunchasak C.
Published: January 2017

The effects were investigated of supplementing methionine (Met) in a low-crude protein diet (Low-CP+Met) during Days 11–24 post-hatch and subsequent feeding with a low-metabolisable energy diet (Low-ME; –0.31 MJ/kg) during Days 25–42 on the productive performance and blood chemistry profile of broiler chickens. The 1600 broiler chicks were divided into four groups and fed as follows: (1) Control diet; (2) Low-CP (Met deficiency) diet during Days 11–24, then re-feeding with conventional diet; (3) Low-CP+Met diet during days 11–24, then re-feeding with conventional diet; and (4) Low-CP+Met+Low-ME diet (Low-CP+Met diet during Days 11–24, then re-feeding with Low-ME diet). During Days 11–24, the growth performance of the Control group was better than the other groups (P < 0.01), although the Low-CP+Met diet improved bodyweight, feed conversion ratio and improved the protein conversion ratio compare to the Low-CP group (P < 0.01). During the re-feeding phase (Days 25–42), reducing the dietary energy resulted in better growth performance and a better protein conversion ratio and energy conversion ratio than in the Control group (P < 0.05). Triglyceride, very low-density lipoprotein, low-density lipoprotein-cholesterol and total cholesterol in serum were higher, and non-esterified fatty acid was lower in the Control group than those of the Low-CP+Met+Low-ME group (P < 0.05). In conclusion, reducing dietary protein with balanced amino acids during the grower period and subsequent feeding with a low-energy diet promoted productive performance, improved protein utilisation and reduced fat accumulation via increasing lipolysis and/or disruption of the triglyceride transportation in broiler chickens.
Infrastructure mitigates the sensitivity of child growth to local agriculture and rainfall in Nepal and Uganda
Authors: Shively Gerald E.
Published: January 2017

Significance

Incorporating agriculture into nutrition policy requires an understanding of how agricultural performance, rainfall, and the economic and physical environments in which children reside relate to linear growth and weight gain. This paper combines anthropometric data from children below the age of 5 y in Nepal and Uganda with rainfall data and other information to measure these connections. Anthropometric outcomes are positively correlated with rainfall prior to birth, during the first year, and during agricultural growing seasons preceding child measurement. High rainfall is found to be deleterious to child growth in some settings. Evidence points to the need for agricultural adaptation to low rainfall, as well as broadly based economic development, including continued investments in health and transport infrastructure, to help improve child nutrition.
Bilateral recruitment of prefrontal cortex in working memory is associated with task demand but not with age
Authors: Höller-Wallscheid Melanie S. , Thier Peter , Pomper Jörn K. , Lindner Axel
Published: January 2017

Significance

One principle of human cerebral cortex is its lateralized functional architecture supporting processes such as language, precise motor control of the hands, and working memory. It has been shown that in elderly subjects such lateralized activations of dorsolateral and anterior prefrontal cortex vanish in working memory tasks, which is due to the corecruitment of corresponding regions in the other cerebral hemisphere. We show that such corecruitment of cross-hemispheric counterparts in prefrontal cortex is associated with subjectively demanding working memory tasks but not with age. This result suggests that prefrontal areas support us to maintain performance in challenging circumstances by additionally recruiting their non-specialized counterpart in the contralateral hemisphere.
Holocene ENSO-related cyclic storms recorded by magnetic minerals in speleothems of central China
Authors: Zhu Zongmin , Feinberg Joshua M. , Xie Shucheng , Bourne Mark D. , Huang Chunju , Hu Chaoyong , Cheng Hai
Published: January 2017

Significance

High-resolution reconstructions of storm history and storms’ underlying mechanisms in inland areas are critical but limited by a paucity of suitable paleoproxies. Here we use soil-derived magnetic minerals preserved in a stalagmite as a new paleohydrological proxy. This proxy enables us to rebuild decadal resolution storm records in the eastern Asian monsoon area since 8.6 ky. Variance of storms in central China was found to exhibit close correlation with El Niño−Southern Oscillation activity at millennial and centennial time scales, and also occur on a significant 500-y cycle related to periodic solar activity. These findings shed light on the forecasting of future floods and improve our understanding of the potential mechanism of strong precipitation in monsoon regions.
Crystal structure of Pistol, a class of self-cleaving ribozyme
Authors: Nguyen Laura A. , Wang Jimin , Steitz Thomas A.
Published: January 2017

Significance

Based on the “RNA world” theory, ribozymes likely carried out biochemical reactions long before organisms evolved to use protein enzymes as biocatalysts. The continued discovery of new structures for small self-cleaving ribozymes has shed light on conserved mechanisms in evolution, such as acid–base catalysis for self-cleavage reaction. Here, we present the crystal structure of a newly discovered class of self-cleaving ribozymes called Pistol and how it likely uses the phosphoester transfer mechanism for self-cleavage. The results presented here suggest that Pistol uses an evolutionarily conserved cleavage mechanism that is like other self-cleaving ribozymes, such as Twister, Hammerhead, Hairpin, and Hepatitis Delta Virus ribozymes.
Prion replication without host adaptation during interspecies transmissions
Authors: Bian Jifeng , Khaychuk Vadim , Angers Rachel C. , Fernández-Borges Natalia , Vidal Enric , Meyerett-Reid Crystal , Kim Sehun , Calvi Carla L. , Bartz Jason C. , Hoover Edward A. , Agrimi Umberto , Richt Jürgen A. , Castilla Joaquín , Telling Glenn C.
Published: January 2017

Significance

To study mechanisms of interspecies prion transmission, we used transgenic mice that recapitulate natural disease susceptibilities. Predictably, prions from a particular species inefficiently caused disease in mice expressing prion proteins from different species. However, in contrast to the expected adaptation that allows efficient prion replication in the new host, we discovered a process in which pathogenic prions, despite causing disease on primary passage, failed to adapt for sustained propagation in the new host, instead preserving the strain and host range characteristics of the original prions. Our findings provide insights into how prions replicate during species transitions, help clarify unresolved epidemiological features of prion disorders, and have considerable bearing on future disease risk assessments.
Zero-index structures as an alternative platform for quantum optics
Authors: Liberal Iñigo , Engheta Nader
Published: January 2017

Significance

Metamaterials provide additional venues for routing and shaping waves, as well as manipulating wave–matter interactions. In principle, similar concepts and techniques could be applied to engineer the properties of quantized fields. Here, we theoretically demonstrate that structures with a near-zero refractive index are capable of inhibiting and then selectively exciting electric field vacuum fluctuations. This effect might offer different pathways to manipulate quantized fields with metamaterials. We illustrate this point by investigating the decay dynamics of a quantum emitter embedded in a zero-index shell. For this particular example, we theoretically show how the distinctive features of zero-index media enable unique phenomena, such as a direct modulation of the vacuum Rabi frequency by deforming the zero-index shell.
Competition of calcified calmodulin N lobe and PIP2to an LQT mutation site in Kv7.1 channel
Authors: Tobelaim William Sam , Dvir Meidan , Lebel Guy , Cui Meng , Buki Tal , Peretz Asher , Marom Milit , Haitin Yoni , Logothetis Diomedes E. , Hirsch Joel Alan , Attali Bernard
Published: January 2017

Significance

Voltage-gated potassium 7.1 (Kv7.1) channel and KCNE1 protein coassembly forms the IKSK+current that repolarizes the cardiac action potential, and mutations inKv7.1andKCNE1genes cause cardiac arrhythmias. The proximal Kv7.1 C terminus binds calmodulin and the phospholipid phosphatidylinositol-4,5-bisphosphate (PIP2); however, it is unknown whether their binding sites overlap physically and functionally. Here, we reveal the competition of PIP2and the calcified form of the calmodulin N lobe to a previously unidentified site in helix B of the proximal Kv7.1 C terminus. Notably, this site bears a mutation causing a cardiac arrhythmia called the long-QT syndrome. Our results suggest that, after receptor-mediated PIP2depletion and increased cytosolic Ca2+, calcified calmodulin N lobe interacts with helix B in place of PIP2to limit excessive IKScurrent depression.
Biosynthesis of the microtubule-destabilizing diterpene pseudolaric acid B from golden larch involves an unusual diterpene synthase
Authors: Mafu Sibongile , Karunanithi Prema Sambandaswami , Palazzo Teresa Ann , Harrod Bronwyn Lee , Rodriguez Selina Marakana , Mollhoff Iris Natalie , O’Brien Terrence Edward , Tong Shen , Fiehn Oliver , Tantillo Dean J. , Bohlmann Jörg , Zerbe Philipp
Published: January 2017

Significance

Diterpenes play important roles in plant biology and serve as industrial bioproducts and therapeutics, including the anticancer drug Taxol. Enzymes of the diterpene synthase family produce the many core structural scaffolds that form the foundation of the large diversity of biologically active diterpenes. This paper describes the identification and the mechanism of a distinct diterpene synthase, pseudolaratriene synthase, from the golden larch tree,
Pseudolarix amabilis
. The enzyme catalyzes the first committed reaction in the biosynthesis of pseudolaric acids, complex diterpenes with potential anticancer activity.
Tissue dual RNA-seq allows fast discovery of infection-specific functions and riboregulators shaping host–pathogen transcriptomes
Authors: Nuss Aaron M. , Beckstette Michael , Pimenova Maria , Schmühl Carina , Opitz Wiebke , Pisano Fabio , Heroven Ann Kathrin , Dersch Petra
Published: January 2017

Significance

Our knowledge of the functions required by extracellular bacterial pathogens to grow in host tissues is still limited. Most available information refers to studies conducted under laboratory growth conditions that mimic host environments but exclude the influence of the host immune system. Tissue dual RNA sequencing allows simultaneous transcript profiling of a pathogen and its infected host. This sensitive approach led to the identification of host immune responses and virulence-relevant bacterial functions that were not previously reported in the context of a
Yersinia
infection. Application of this tool will allow transcript profiling of other pathogens to unravel concealed gene functions that are crucial for survival in different host niches and will improve identification of potential drug targets.
Conserved GTPase LepA (Elongation Factor 4) functions in biogenesis of the 30S subunit of the 70S ribosome
Authors: Gibbs Michelle R. , Moon Kyung-Mee , Chen Menglin , Balakrishnan Rohan , Foster Leonard J. , Fredrick Kurt
Published: January 2017

Significance

The translational GTPase LepA is a highly conserved bacterial protein whose role in the cell has been elusive. Here, we show that the function of LepA lies in biogenesis of the 30S subunit of the ribosome, rather than in translation elongation, as previously supposed. Loss of LepA results in the accumulation of immature 30S particles lacking certain proteins of the 3′ (head) domain and containing precursor 17S rRNA. The GTPase activity of LepA, like that of other translational GTPases, is stimulated by interactions with both subunits of the ribosome. This implies that LepA acts at a late stage of assembly, in the context of the 70S ribosome.
Comparative genomics reveals convergent evolution between the bamboo-eating giant and red pandas
Authors: Hu Yibo , Wu Qi , Ma Shuai , Ma Tianxiao , Shan Lei , Wang Xiao , Nie Yonggang , Ning Zemin , Yan Li , Xiu Yunfang , Wei Fuwen
Published: January 2017

Significance

The giant panda and red panda are obligate bamboo-feeders that independently evolved from meat-eating ancestors and possess adaptive pseudothumbs, making them ideal models for studying convergent evolution. In this study, we identified genomic signatures of convergent evolution associated with bamboo eating. Comparative genomic analyses revealed adaptively convergent genes potentially involved with pseudothumb development and essential bamboo nutrient utilization. We also found that the umami taste receptor gene
TAS1R1
has been pseudogenized in both pandas. These findings provide insights into genetic mechanisms underlying phenotypic convergence and adaptation to a specialized bamboo diet in both pandas and offer an example of genome-scale analyses for detecting convergent evolution.
Ontogenetic and life history trait changes associated with convergent ecological specializations in extinct ungulate mammals
Authors: Gomes Rodrigues Helder , Herrel Anthony , Billet Guillaume
Published: January 2017

Significance

Estimating life history traits such as pace of growth or longevity is difficult in extinct mammals. Yet, these parameters could be helpful to better understand how herbivorous mammals adapted to changing environments. We here highlight the insights gained by studying dental growth and eruption in a clade of extinct ungulate mammals. Variation in these traits was assessed in the context of volcanism, cooling, and increasing aridity in South America starting 50 Ma. We show that ever-growing teeth combined with faster molar eruption arose several times during the evolution of these mammals, allowing them to obtain a more durable and efficient dentition in constraining environments. These innovations might represent convergent ontogenetic and physiological adjustments that contributed to their ecological specialization.
Fragility of the provision of local public goods to private and collective risks
Authors: Cárdenas Juan-Camilo , Janssen Marco A. , Ale Manita , Bastakoti Ram , Bernal Adriana , Chalermphol Juthathip , Gong Yazhen , Shin Hoon , Shivakoti Ganesh , Wang Yibo , Anderies John M.
Published: January 2017

Significance

Smallholder farmers make a significant contribution to food security in developing countries. Those farmer communities are experiencing new challenges owing to integration with the broader economy (increasing price volatility) and climate change (increasing frequency of extreme weather events). Our study aimed to understand how smallholder agricultural communities make collective action decisions in a public good game with different types of risks. Experiments performed in 118 small-scale rice-producing communities in China, Colombia, Nepal and Thailand show that increasing the integration of those communities with the broader economic system is associated with lower investments in public goods when facing collective risks. As such, the provision of local public goods may be negatively affected by market integration and climate change.
Hepatitis E virus ORF3 is a functional ion channel required for release of infectious particles
Authors: Ding Qiang , Heller Brigitte , Capuccino Juan M. V. , Song Bokai , Nimgaonkar Ila , Hrebikova Gabriela , Contreras Jorge E. , Ploss Alexander
Published: January 2017

Significance

Hepatitis E virus (HEV) is responsible for an estimated 20 million enterically transmitted cases of viral hepatitis globally. Here, we demonstrate that one of HEV’s three major gene products, ORF3, is an ion channel. Deletion of ORF3 abrogates release of infectious virions, and we show that viral egress can be rescued by expressing the influenza A virus (IAV) matrix-2 protein
in trans
. Expression of ORF3 facilitates ion flux across the plasma membrane, providing direct evidence for its viroporin activity. We identify regions within ORF3 abrogating both ion channel activity and particle release, thereby linking these two processes for a quasienveloped human virus and providing an attractive potential target for antiviral drug development.
Molecular mechanism underlying juvenile hormone-mediated repression of precocious larval–adult metamorphosis
Authors: Kayukawa Takumi , Jouraku Akiya , Ito Yuka , Shinoda Tetsuro
Published: January 2017

Significance

Juvenile hormone (JH) intricately controls molting and metamorphosis in holometabolous insects.Ecdysone-induced protein 93F(E93) functions as an adult specifier gene in the pupal–adult transition. JH is known to repressE93expression to prevent immature larvae from bypassing the pupal stage and progressing to precocious adult development; however, the molecular mechanism underlying JH-mediatedE93repression remains unknown. Here, we demonstrated that JH-inducible Krüppel homolog 1 functions as a direct transcriptional repressor ofE93. This study markedly advances the present understanding of the molecular basis of JH function in repressing insect metamorphosis.
Hydrogen isotope fractionation in methane plasma
Authors: Robert François , Derenne Sylvie , Lombardi Guillaume , Hassouni Khaled , Michau Armelle , Reinhardt Peter , Duhamel Rémi , Gonzalez Adriana , Biron Kasia
Published: January 2017

Significance

Large variations in light element isotope ratios (H, N, C) are routinely observed in meteorite organic matter. The origin of these so-called anomalies is not accounted for by the classical theory of isotope fractionation. In the case of H, micrometer-size areas within the insoluble organic matter (IOM) isolated from meteorites by acid treatment, exhibit extreme deuterium enrichment. They are generally interpreted as components exogenous to the solar system and attributed to surviving interstellar grains. In the present paper, these H isotope anomalies were reproduced in the IOM synthesized through laboratory reactions involving CH
x
•
radicals formed in CH
4
plasma. Therefore, these anomalies may result from the chemistry occurring in the disk surrounding the Sun during its formation.