bluuebunny/crossref_metadata_2025 huggingface dataset:
Finite‐time state‐feedback stabilisation of non‐holonomic systems with low‐order non‐linearities
Authors: Wu Yuqiang , Gao Fangzheng , Liu Zhenguo
Published: May 2015

This study investigates the problem of finite‐time stabilisation by state feedback for a class of non‐holonomic systems in chained form with low‐order non‐linearities, to which the existing control methods are inapplicable. By introducing sign function and necessarily modifying the method of adding a power integrator, a state‐feedback controller is successfully constructed. Together with a novel switching control strategy, the designed controller guarantees that the states of closed‐loop system are regulated to zero in a finite time. A simulation example is provided to illustrate the effectiveness of the proposed approach.
Vehicle routing problem solution considering minimising fuel consumption
Authors: Yao Enjian , Lang Zhifeng , Yang Yang , Zhang Yongsheng
Published: May 2015

Recently, logistics is not only playing more and more important role in social and economic development, but also caused serious energy consumption and environment pollution problems. Reasonable vehicle route planning is viewed as an important solution to reduce logistics enterprises’ operation costs as well as alleviate the energy and environmental problems. This study aims to propose a solution to time‐dependent vehicle routing problem with time windows (TDVRPTW) considering minimising fuel consumption. First, a mathematical TDVRPTW model with the minimum fuel consumption as an objective function is established, in which the three‐dimensional bin‐packing problem is considered as a sub‐problem and the alternative stop point concept is newly proposed to reduce the possible detouring distance and fuel consumption of logistic vehicle. Then, an ant colony algorithm is applied to solve the problem, and the departure time optimisation is introduced to further improve the obtained results. Finally, the proposed approach is evaluated with the real road network and traffic data of Beijing. The results show that the method introduced in this study outperforms the existing approaches in reducing fuel consumption as well as route length.
Meteorological phenomena associated with wind-power ramps downwind of mountainous terrain
Authors: Sherry M. , Rival D.
Published: May 2015

Wind-power ramps are a significant source of uncertainty in wind-energy forecasting and are a challenge to electric-grid stability. In the Canadian province of Alberta, strong westerly winds buffet the Rocky Mountains creating an abundant yet intermittent wind energy resource in the plains of Alberta. In the current study, wind-power ramp events have been detected and correlated to several environmental factors including time-of-day, atmospheric stability, season and a Föhn wind event known locally as a Chinook wind at a field wind measurement station downstream of the Rocky Mountains. Large wind-power ramps (a 50% change in power in less than 4 h) were found to occur on days when a Föhn wind was present over 50% of the time. The result highlights the importance of this meteorological phenomenon to wind energy production locally and also in regions where Föhn winds occur. The detected wind-power ramps were found to vary significantly with season, with the strongest wind-power ramps emanating from the Rocky Mountains in the winter months under stable atmospheric conditions.
Tailoring wall permeabilities for enhanced filtration
Authors: Herterich J. G. , Vella D. , Field R. W. , Hankins N. P. , Griffiths I. M.
Published: May 2015

The build-up of contaminants at the wall of cross-flow membrane filtration systems can be detrimental to the operation of such systems because of, amongst other things, the osmotic backflow it may induce. In this paper, we propose a strategy to avoid the negative effects of backflow due to osmosis by using 2D channels bounded by walls with a combination of permeable and impermeable segments. We show that preventing flow through the final portion of the channel can increase the efficiency of filtration and we determine the optimal fraction occupied by the permeable wall that maximizes efficiency. Our analysis uses a combination of numerical techniques and asymptotic analysis in the limit of low wall permeabilities. Finally, we consider how the energy cost of filtration depends on the Péclet number and show that the energy cost per unit of filtered water may be minimized by appropriately choosing both the Péclet number and the permeable-region fraction.
Jet cooled cavity ringdown spectroscopy of the A˜2E″←X˜2A2′ transition of the NO3 radical
Authors: Codd Terrance , Chen Ming-Wei , Roudjane Mourad , Stanton John F. , Miller Terry A.
Published: May 2015

The A˜2E″←X˜2A2′ spectrum of NO3 radical from 7550 cm−1 to 9750 cm−1 has been recorded and analyzed. Our spectrum differs from previously recorded spectra of this transition due to jet-cooling, which narrows the rotational contours and eliminates spectral interference from hot bands. Assignments of numerous vibronic features can be made based on both band contour and position including the previously unassigned 301 band and several associated combination bands. We have analyzed our spectrum first with an independent anharmonic oscillator model and then by a quadratic Jahn-Teller vibronic coupling model. The fit achieved with the quadratic Jahn-Teller model is excellent, but the potential energy surface obtained with the fitted parameters is in only qualitative agreement with one obtained from ab initio calculations.
Dielectric constant of water as a function of separation in a slab geometry: A molecular dynamics study
Authors: Itoh Hidenosuke , Sakuma Hiroshi
Published: May 2015

Water in confining geometries shows various anomalous properties related to its structure and dynamics compared with bulk water. Here, the dielectric constant of water as a function of separation in a graphite slab geometry was studied using molecular dynamics simulations. The dielectric constants of water were calculated from the orientational polarization of water molecules when an external electric field was applied parallel and normal to the slabs. The reduction of the dielectric constant of water compared with bulk water can be explained by investigating the structure and dynamics of water in slab geometries. We found a preferred orientation of water molecules in the layer closest to the graphite surface. The self-diffusion coefficient distribution of water molecules along the direction normal to the slabs was also computed. Highly mobile water molecules in the intermediate region were generated by the weak hydrogen bonding produced by the preferred orientation of water molecules in the layer. We concluded that the dielectric constant of water in the slab geometry is lower than that of bulk water because of the reduction of the polarization of water and the highly mobile water molecules in the intermediate region arising from the preferred orientation of water molecules.
Molecular simulations of heterogeneous ice nucleation. II. Peeling back the layers
Authors: Cox Stephen J. , Kathmann Shawn M. , Slater Ben , Michaelides Angelos
Published: May 2015

Coarse grained molecular dynamics simulations are presented in which the sensitivity of the ice nucleation rate to the hydrophilicity of a graphene nanoflake is investigated. We find that an optimal interaction strength for promoting ice nucleation exists, which coincides with that found previously for a face centered cubic (111) surface. We further investigate the role that the layering of interfacial water plays in heterogeneous ice nucleation and demonstrate that the extent of layering is not a good indicator of ice nucleating ability for all surfaces. Our results suggest that to be an efficient ice nucleating agent, a surface should not bind water too strongly if it is able to accommodate high coverages of water.
Fluid flow induced by periodic temperature oscillation over a flat plate: Comparisons with the classical Stokes problems
Authors: Pal Debashis , Chakraborty Suman
Published: May 2015

We delineate the dynamics of temporally and spatially periodic flow over a flat plate originating out of periodic thermoviscous expansion of the fluid, as a consequence of a thermal wave applied on the plate wall. We identify two appropriate length scales, namely, the wavelength of the temperature wave and the thermal penetration depth, so as to bring out the complex thermo-physical interaction between the fluid and the solid boundaries. Our results reveal that the entire thermal fluctuation and the subsequent thermoviscous actuation remain confined within a “thermo-viscous boundary layer.” Based on the length scales and the analytical solution for the temperature field, we demarcate three different layers, namely, the wall layer (which is further sub-divided into various sub-layers, based on the temperature field), the intermediate layer, and the outer layer. We show that the interactions between the pressure oscillation and temperature-dependent viscosity yield a unidirectional time-averaged (mean) flow within the wall layer opposite to the direction of motion of the thermal wave. We also obtain appropriate scalings for the time-averaged velocity, which we further substantiate by full scale numerical simulations. Our analysis may constitute a new design basis for simultaneous control of the net throughput and mixing over a solid boundary, by the judicious employment of a traveling temperature wave.
Probing polariton dynamics in trapped ions with phase-coherent two-dimensional spectroscopy
Authors: Gessner Manuel , Schlawin Frank , Buchleitner Andreas
Published: May 2015

We devise a phase-coherent three-pulse protocol to probe the polariton dynamics in a trapped-ion quantum simulation. In contrast to conventional nonlinear signals, the presented scheme does not change the number of excitations in the system, allowing for the investigation of the dynamics within an N-excitation manifold. In the particular case of a filling factor one (N excitations in an N-ion chain), the proposed interaction induces coherent transitions between a delocalized phonon superfluid and a localized atomic insulator phase. Numerical simulations of a two-ion chain demonstrate that the resulting two-dimensional spectra allow for the unambiguous identification of the distinct phases, and the two-dimensional line shapes efficiently characterize the relevant decoherence mechanism.
Resonances in positron-hydrogen scattering in dense quantum plasmas
Authors: Jiang Zishi , Zhang Yong-Zhi , Kar Sabyasachi
Published: May 2015

We have investigated the S-wave resonance states in positron-hydrogen system embedded in dense quantum plasmas using Hylleraas-type wave functions within the framework of the stabilization method. The effect of quantum plasmas has been incorporated using the exponential-cosine-screened Coulomb (modified Yukawa-type) potential. Resonance parameters (both position and width) below the Ps n = 2 threshold are reported as functions of plasma screening parameters.
Riemann equation for prime number diffusion
Authors: Chen Wen , Liang Yingjie
Published: May 2015

This study makes the first attempt to propose the Riemann diffusion equation to describe in a manner of partial differential equation and interpret in physics of diffusion the classical Riemann method for prime number distribution. The analytical solution of this equation is the well-known Riemann representation. The diffusion coefficient is dependent on natural number, a kind of position-dependent diffusivity diffusion. We find that the diffusion coefficient of the Riemann diffusion equation is nearly a straight line having a slope 0.99734 in the double-logarithmic axis. Consequently, an approximate solution of the Riemann diffusion equation is obtained, which agrees well with the Riemann representation in predicting the prime number distribution. Moreover, we interpret the scale-free property of prime number distribution via a power law function with 1.0169 the scale-free exponent in respect to logarithmic transform of the natural number, and then the fractal characteristic of prime number distribution is disclosed.
Validating hydrodynamic growth in National Ignition Facility implosions
Authors: Peterson J. L. , Casey D. T. , Hurricane O. A. , Raman K. S. , Robey H. F. , Smalyuk V. A.
Published: May 2015

We present new hydrodynamic growth experiments at the National Ignition Facility, which extend previous measurements up to Legendre mode 160 and convergence ratio 4, continuing the growth factor dispersion curve comparison of the low foot and high foot pulses reported by Casey et al. [Phys. Rev. E 90, 011102(R) (2014)]. We show that the high foot pulse has lower growth factor and lower growth rate than the low foot pulse. Using novel on-capsule fiducial markers, we observe that mode 160 inverts sign (changes phase) for the high foot pulse, evidence of amplitude oscillations during the Richtmyer-Meshkov phase of a spherically convergent system. Post-shot simulations are consistent with the experimental measurements for all but the shortest wavelength perturbations, reinforcing the validity of radiation hydrodynamic simulations of ablation front growth in inertial confinement fusion capsules.
Spherical strong-shock generation for shock-ignition inertial fusion
Authors: Theobald W. , Nora R. , Seka W. , Lafon M. , Anderson K. S. , Hohenberger M. , Marshall F. J. , Michel D. T. , Solodov A. A. , Stoeckl C. , Edgell D. H. , Yaakobi B. , Casner A. , Reverdin C. , Ribeyre X. , Shvydky A. , Vallet A. , Peebles J. , Beg F. N. , Wei M. S. , Betti R.
Published: May 2015

Recent experiments on the Laboratory for Laser Energetics' OMEGA laser have been carried out to produce strong shocks in solid spherical targets with direct laser illumination. The shocks are launched at pressures of several hundred Mbars and reach Gbar upon convergence. The results are relevant to the validation of the shock-ignition scheme and to the development of an OMEGA experimental platform to study material properties at Gbar pressures. The experiments investigate the strength of the ablation pressure and the hot-electron production at incident laser intensities of ∼2 to 6 × 1015 W/cm2 and demonstrate ablation pressures exceeding 300 Mbar, which is crucial to developing a shock-ignition target design for the National Ignition Facility. The timing of the x-ray flash from shock convergence in the center of the solid plastic target is used to infer the ablation and shock pressures. Laser–plasma instabilities produce hot-electrons with a moderate temperature (<100 keV). The instantaneous conversion efficiencies of laser power into hot-electron power reached up to ∼15% in the intensity spike. The large amount of hot electrons is correlated with an earlier x-ray flash and a strong increase in its magnitude. This suggests that hot electrons contribute to the augmentation of the shock strength.
In situ transmission electron microscopy of individual carbon nanotetrahedron/ribbon structures in bending
Authors: Kohno Hideo , Masuda Yusuke
Published: May 2015

When the direction of flattening of a carbon nanotube changes during growth mediated by a metal nanoparticle, a carbon nanotetrahedron is formed in the middle of the carbon nanoribbon. We report the bending properties of the carbon nanotetrahedron/nanoribbon structure using a micro-manipulator system in a transmission electron microscope. In many cases, bending occurs at an edge of the carbon nanotetrahedron. No significant change is observed in the tetrahedron's shape during bending, and the bending is reversible and repeatable. Our results show that the carbon nanotetrahedron/nanoribbon structure has good durability against mechanical bending.
Magnetoelectric sensor excitations in hexaferrite films
Authors: Zare Saba , Rabinowitz Jake , Izadkhah Hessam , Somu Sivasubramanian , Vittoria Carmine
Published: May 2015

We developed techniques for H- and E-field sensors utilizing single phase magnetoelectric (ME) hexaferrite thin films in the frequency range of 1 kHz to 10 MHz. The technique incorporating solenoid coils and multi-capacitors bank was developed to probe the physics and properties of ME hexaferrite film and explore ME effects for sensor detections and tunable device applications. For H-field sensing, we obtained sensitivity of 4 × 10−4 V/Gm and for E-field sensing the sensitivity was 10−3 Gm/V. Tunability of up to 6% was achieved for tunable inductor applications. The proposed fabrication designs lend themselves to significant (∼106) improvements in sensitivity and tunability.
Communication: Water on hexagonal boron nitride from diffusion Monte Carlo
Authors: Al-Hamdani Yasmine S. , Ma Ming , Alfè Dario , von Lilienfeld O. Anatole , Michaelides Angelos
Published: May 2015

Despite a recent flurry of experimental and simulation studies, an accurate estimate of the interaction strength of water molecules with hexagonal boron nitride is lacking. Here, we report quantum Monte Carlo results for the adsorption of a water monomer on a periodic hexagonal boron nitride sheet, which yield a water monomer interaction energy of −84 ± 5 meV. We use the results to evaluate the performance of several widely used density functional theory (DFT) exchange correlation functionals and find that they all deviate substantially. Differences in interaction energies between different adsorption sites are however better reproduced by DFT.
Electron beam assisted field evaporation of insulating nanowires/tubes
Authors: Blanchard N. P. , Niguès A. , Choueib M. , Perisanu S. , Ayari A. , Poncharal P. , Purcell S. T. , Siria A. , Vincent P.
Published: May 2015

We demonstrate field evaporation of insulating materials, specifically BN nanotubes and undoped Si nanowires, assisted by a convergent electron beam. Electron irradiation leads to positive charging at the nano-object's apex and to an important increase of the local electric field thus inducing field evaporation. Experiments performed both in a transmission electron microscope and in a scanning electron microscope are presented. This technique permits the selective evaporation of individual nanowires in complex materials. Electron assisted field evaporation could be an interesting alternative or complementary to laser induced field desorption used in atom probe tomography of insulating materials.
Octagonal toroid microcavity for mechanically robust optical coupling
Authors: Suzuki Ryo , Kato Takumi , Tetsumoto Tomohiro , Tanabe Takasumi
Published: May 2015

Light is usually coupled to a whispering gallery mode cavity using a tapered fiber. However, it is difficult to stabilize the optical coupling against mechanical vibration because it requires sub-μm control of the gap distance between the fiber and cavity. In this study, we experimentally demonstrate mechanically robust coupling that we realize by allowing the tapered fiber to touch the sidewall of the cavity. By using an octagonal toroid microcavity, we prevent the cavity-waveguide system from over coupling and achieve critical coupling even when the fiber is in contact with the surface of the cavity. We show by numerical analysis that such a deformed microcavity is required if we need to control the coupling, since a circular cavity usually overcouples when the fiber contacts the surface. The fabricated octagonal silica toroid microcavity exhibits a quality factor of 2.2 × 104 when the tapered fiber touches a cavity with a diameter of 80 μm.
Ciguatera toxins in wild coral reef fish along the southern coast of China
Authors: Wu Ni , Huan Qingliu , Du Kemei , Hu Rong , Jiang Tian-jiu
Published: May 2015

Ciguatera toxins (CTXs) in wild coral reef fish collected from the southern coast of China were analysed. Cigua-Check kits were used for primary screening. Mouse bioassay was used to quantify toxins of the samples identified as positive by the Cigua-Check kit. High-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) was used to further analyse P-CTX-1 of ciguatera toxins in the samples identified as positive by the mouse bioassay. The mouse bioassay showed that ciguatoxic fish existed in all six sampling sites, and 47.8% of the samples were confirmed to be contaminated with CTXs. The implicated species largely belonged to Chaetodontidae, Scaridae, Holocentridae, Lutjanidae and Serranidae. The toxicities varied from 0 to 169ng P-CTX-1kg–1 fish flesh according to mouse bioassay. There was no significant correlation between fish toxicity and fish weight, length and feeding habits. The accuracy rate of the Cigua-Check kit in judging toxicity or non-toxicity was up to 95.7% according to the mouse bioassay. However, the Cigua-Check kit and mouse bioassay differed significantly with respect to measures of toxicity. According to HPLC–MS/MS, no P-CTX-1 was identified in any of the samples that the mouse bioassay identified as positive.
GIRK3 gates activation of the mesolimbic dopaminergic pathway by ethanol
Authors: Herman Melissa A. , Sidhu Harpreet , Stouffer David G. , Kreifeldt Max , Le David , Cates-Gatto Chelsea , Munoz Michaelanne B. , Roberts Amanda J. , Parsons Loren H. , Roberto Marisa , Wickman Kevin , Slesinger Paul A. , Contet Candice
Published: May 2015

Significance

G protein-gated inwardly rectifying potassium (GIRK) channels regulate neuronal excitability and can be activated by ethanol. The role of GIRK channels in the behavioral effects of ethanol is poorly understood, however. This study shows that genetic ablation of GIRK3, one of four GIRK subunits, prevents ethanol from activating the mesolimbic dopaminergic pathway, a neuronal circuit subserving the motivation to seek reward (incentive salience), and enhances binge-like drinking. Conversely, increasing GIRK3 expression in the ventral midbrain, where this pathway originates, reduces binge-like drinking. Thus, GIRK3 appears to be a critical gatekeeper of ethanol incentive salience and a potential target for the treatment of excessive ethanol consumption.
Climatic dipoles drive two principal modes of North American boreal bird irruption
Authors: Strong Courtenay , Zuckerberg Benjamin , Betancourt Julio L. , Koenig Walter D.
Published: May 2015

Significance

This study is the first, to our knowledge, to reveal how climate variability drives irruptions of North American boreal seed-eating birds. Patterns of Pine Siskin irruption and associated climate drivers manifest as two modes (North-South and West-East) in which dipoles of temperature and precipitation anomalies push and pull irruptive movements across the continent at biennial to decadal periodicities. Our study accentuates the value of sustained and synoptic biological observations, contributed by citizen scientists in this case, that match the spatial and temporal scales at which climatic phenomena are observed and understood. Such observations can help probe new questions, such as the role of climatic dipoles in other large-scale ecological processes.
Severity of ocean acidification following the end-Cretaceous asteroid impact
Authors: Tyrrell Toby , Merico Agostino , Armstrong McKay David Ian
Published: May 2015

Significance

Ammonites went extinct at the time of the end-Cretaceous asteroid impact, as did more than 90% of species of calcium carbonate-shelled plankton (coccolithophores and foraminifera). Comparable groups not possessing calcium carbonate shells were less severely affected, raising the possibility that ocean acidification, as a side effect of the collision, might have been responsible for the apparent selectivity of the extinctions. We investigated whether ocean acidification could have caused the disappearance of the calcifying organisms. In a first detailed modelling study we simulated several possible mechanisms from impact to seawater acidification. Our results suggest that acidification was most probably not the cause of the extinctions.
Immune-checkpoint proteins VISTA and PD-1 nonredundantly regulate murine T-cell responses
Authors: Liu Jun , Yuan Ying , Chen Wenna , Putra Juan , Suriawinata Arief A. , Schenk Austin D. , Miller Halli E. , Guleria Indira , Barth Richard J. , Huang Yina H. , Wang Li
Published: May 2015

Significance

Multiple immune-checkpoint proteins, such as programmed death 1 (PD-1), LAG3, and TIM3, are coexpressed on immune cells and functionally synergize with each other. V-domain immunoglobulin suppressor of T-cell activation (VISTA) is a recently identified immune-checkpoint molecule that suppresses T-cell activation. This study establishes that VISTA and PD-1 exert nonredundant immune regulatory functions and synergistically regulate T-cell responses. Combinatorial treatment using VISTA- and PD-ligand 1-specific monoclonal antibodies achieved synergistic therapeutic efficacy in murine tumor models. This study critically advances our knowledge of the immune regulatory function of VISTA and provides a rationale for targeting both VISTA and PD-1 to more effectively treat T-cell-regulated diseases such as cancer.
The rise of oxygen and siderite oxidation during the Lomagundi Event
Authors: Bachan Aviv , Kump Lee R.
Published: May 2015

Significance

The evolution of Earth’s oxygen-rich atmosphere occurred in two major steps, the first of which took place approximately 2.4 billion years ago. Following the initial rise of oxygen, carbon isotope evidence indicates the burial of vast quantities of organic carbon and the production of correspondingly large amounts of oxygen. However, if not accompanied by an additional supply of carbon, the extreme levels of organic carbon burial imply nonphysically low atmospheric
p
CO
2
levels. Here we propose that the initial rise in O
2
led to the oxidation of a large preexisting reservoir of siderite (FeCO
3
), which provided the necessary carbon for the burial of organic matter, production of further O
2
, and substantial accumulation of oxygen in Earth’s atmosphere for the first time.
Holographic patterning of high-performance on-chip 3D lithium-ion microbatteries
Authors: Ning Hailong , Pikul James H. , Zhang Runyu , Li Xuejiao , Xu Sheng , Wang Junjie , Rogers John A. , King William P. , Braun Paul V.
Published: May 2015

Significance

Microscale batteries can deliver energy at the actual point of energy usage, providing capabilities for miniaturizing electronic devices and enhancing their performance. Here, we demonstrate a high-performance microbattery suitable for large-scale on-chip integration with both microelectromechanical and complementary metal-oxide–semiconductor (CMOS) devices. Enabled by a 3D holographic patterning technique, the battery possesses well-defined, periodically mesostructured porous electrodes. Such battery architectures offer both high energy and high power, and the 3D holographic patterning technique offers exceptional control of the electrode’s structural parameters, enabling customized energy and power for specific applications.
N
-lactoyl-amino acids are ubiquitous metabolites that originate from CNDP2-mediated reverse proteolysis of lactate and amino acids
Authors: Jansen Robert S. , Addie Ruben , Merkx Remco , Fish Alexander , Mahakena Sunny , Bleijerveld Onno B. , Altelaar Maarten , IJlst Lodewijk , Wanders Ronald J. , Borst P. , van de Wetering Koen
Published: May 2015

Significance

Untargeted metabolomics is rapidly becoming a mainstream technique to discover biomarkers, to study the effects of interventions, and to discover the function of enzymes. Several thousand metabolites can be detected in a single untargeted metabolomics analysis, but state-of-the-art untargeted metabolomics studies still report up to 40% unidentified metabolites, indicating that large parts of the human metabolome are still unexplored. We identified an uncharacterized class of ubiquitous mammalian metabolites:
N
-lactoyl-amino acids. Using a powerful combination of proteomics and protein fractionation, we unexpectedly discovered that these metabolites are formed from lactate and amino acids by reversed action of the protease cytosolic nonspecific dipeptidase 2. Our approach to identify unknown metabolites and their biosynthesis has general applicability in the further exploration of the human metabolome.
A hypothesis to reconcile the physical and chemical unfolding of proteins
Authors: de Oliveira Guilherme A. P. , Silva Jerson L.
Published: May 2015

Significance

A comprehensive view of protein folding is crucial for understanding how misfolding can cause neurodegenerative diseases and cancer. When using physical or chemical perturbations, NMR spectroscopy is a powerful tool to reveal a shift in the native conformation toward local intermediates that act as seeds for misfolding. Using NMR, we show that the ensemble of dry and wet molten-globule intermediates populated by high pressure is different from that found when urea is used. The dissimilar actions of urea and pressure can be summarized by their “pull” and “push” effects, respectively. By combining NMR and small-angle X-ray scattering (SAXS), we demonstrate the action of urea at the initial stages of unfolding and the dominance of a direct interaction mechanism for urea-induced protein denaturation.
A decline in prosocial language helps explain public disapproval of the US Congress
Authors: Frimer Jeremy A. , Aquino Karl , Gebauer Jochen E. , Zhu Luke (Lei) , Oakes Harrison
Published: May 2015

Significance

Past laboratory research has shown that talking about helping others can make a positive impression upon a listener. We tested whether this basic social-cognitive phenomenon can help explain how governments gain the confidence of the public they serve. A computerized text analysis of the debates of the US Congress over the past 20 y found that the density of prosocial language strongly predicted public approval ratings 6 mo later. These results suggest that both individuals and governments can gain social approval by merely talking about cooperating and about helping others.
Circuit-dependent striatal PKA and ERK signaling underlies rapid behavioral shift in mating reaction of male mice
Authors: Goto Akihiro , Nakahara Ichiro , Yamaguchi Takashi , Kamioka Yuji , Sumiyama Kenta , Matsuda Michiyuki , Nakanishi Shigetada , Funabiki Kazuo
Published: May 2015

Significance

Selection of actions that allow the seeking of rewards and avoidance of uncomfortable environments is a fundamental animal behavior. Here, we report an in vivo method, in which the activities of PKA and ERK were optically recorded by microendoscopy of Förster resonance energy transfer responses of biosensors in distinct D1 and D2 dopamine receptor-expressing neurons of the dorsal striatum. The PKA and ERK were coordinately but reciprocally regulated not only by rewarding and aversive stimuli but also between the two parallel projection neurons. Importantly, the cell type-specific regulation of PKA and ERK was causally linked to active and indifferent mating reactions of male mice. The dynamic modulation of PKA and ERK in the striatum underlies the selection of alternative actions.
Resilience and reactivity of global food security
Authors: Suweis Samir , Carr Joel A. , Maritan Amos , Rinaldo Andrea , D’Odorico Paolo
Published: May 2015

Significance

The past few decades have seen an intensification of international food trade and the increase in the number of countries that depend on food imports. As an effect of the associated globalization of food, local shocks in food production, combined with the adoption of new national or regional energy and trade policies, have recently led to global food crises. Here we develop a framework to investigate the coupled global food–population dynamics, and evaluate the effect of international trade on global food security. We find that, as the dependency on trade increases, the global food system is losing resilience and is becoming increasingly unstable and susceptible to conditions of crisis.
Effect of oil droplet size on activation energy for coalescence of oil droplets in an O/W emulsion
Authors: Miyagawa Yayoi , Katsuki Kazutaka , Matsuno Ryuichi , Adachi Shuji
Published: May 2015

The activation energy of a reasonable order of magnitude was estimated for the coalescence of oil droplets in an O/W emulsion by formulating the balance of forces acting on a droplet that crosses over the potential barrier to coalesce with another droplet by the DLVO theory and Stokes’ law. An emulsion with smaller oil droplets was shown to be more stable.
An acidic microenvironment sets the humoral pattern recognition molecule PTX3 in a tissue repair mode
Authors: Doni Andrea , Musso Tiziana , Morone Diego , Bastone Antonio , Zambelli Vanessa , Sironi Marina , Castagnoli Carlotta , Cambieri Irene , Stravalaci Matteo , Pasqualini Fabio , Laface Ilaria , Valentino Sonia , Tartari Silvia , Ponzetta Andrea , Maina Virginia , Barbieri Silvia S. , Tremoli Elena , Catapano Alberico L. , Norata Giuseppe D. , Bottazzi Barbara , Garlanda Cecilia , Mantovani Alberto
Published: May 2015

Pentraxin 3 (PTX3) is a fluid-phase pattern recognition molecule and a key component of the humoral arm of innate immunity. In four different models of tissue damage in mice, PTX3 deficiency was associated with increased fibrin deposition and persistence, and thicker clots, followed by increased collagen deposition, when compared with controls. Ptx3-deficient macrophages showed defective pericellular fibrinolysis in vitro. PTX3-bound fibrinogen/fibrin and plasminogen at acidic pH and increased plasmin-mediated fibrinolysis. The second exon-encoded N-terminal domain of PTX3 recapitulated the activity of the intact molecule. Thus, a prototypic component of humoral innate immunity, PTX3, plays a nonredundant role in the orchestration of tissue repair and remodeling. Tissue acidification resulting from metabolic adaptation during tissue repair sets PTX3 in a tissue remodeling and repair mode, suggesting that matrix and microbial recognition are common, ancestral features of the humoral arm of innate immunity.
Bcl11b is essential for group 2 innate lymphoid cell development
Authors: Walker Jennifer A. , Oliphant Christopher J. , Englezakis Alexandros , Yu Yong , Clare Simon , Rodewald Hans-Reimer , Belz Gabrielle , Liu Pentao , Fallon Padraic G. , McKenzie Andrew N.J.
Published: May 2015

Group 2 innate lymphoid cells (ILC2s) are often found associated with mucosal surfaces where they contribute to protective immunity, inappropriate allergic responses, and tissue repair. Although we know they develop from a common lymphoid progenitor in the bone marrow (BM), the specific lineage path and transcriptional regulators that are involved are only starting to emerge. After ILC2 gene expression analysis we investigated the role of Bcl11b, a factor previously linked to T cell commitment, in ILC2 development. Using combined Bcl11b-tom and Id2-gfp reporter mice, we show that Bcl11b is expressed in ILC2 precursors in the BM and maintained in mature ILC2s. In vivo deletion of Bcl11b, by conditional tamoxifen-induced depletion or by Bcl11b−/− fetal liver chimera reconstitution, demonstrates that ILC2s are wholly dependent on Bcl11b for their development. Notably, in the absence of Bcl11b there is a concomitant expansion of the RORγt+ ILC3 population, suggesting that Bcl11b may negatively regulate this lineage. Using Nippostrongylus brasiliensis infection, we reveal that the absence of Bcl11b leads to impaired worm expulsion, caused by a deficit in ILC2s, whereas Citrobacter rodentium infection is cleared efficiently. These data clearly establish Bcl11b as a new factor in the differentiation of ILC2s.
Localized Properties of Rogue Wave for a Higher-Order Nonlinear Schrödinger Equation*
Authors: Liu Wei , Qiu De-Qin , He Jing-Song
Published: May 2015

In this paper, we provide determinant representation of the n-th order rogue wave solutions for a higher-order nonlinear Schrödinger equation (HONLS) by the Darboux transformation and confirm the decomposition rule of the rogue wave solutions up to fourth-order. These solutions have two parameters α and β which denote the contribution of the higher-order terms (dispersions and nonlinear effects) included in the HONLS equation. Two localized properties, i.e., length and width of the first-order rogue wave solution are expressed by above two parameters, which show analytically a remarkable influence of higher-order terms on the rogue wave. Moreover, profiles of the higher-order rogue wave solutions demonstrate graphically a strong compression effect along t-direction given by higher-order terms.
A Corresponding Lie Algebra of a Reductive homogeneous Group and Its Applications*
Authors: Zhang Yu-Feng , Wu Li-Xin , Rui Wen-Juan
Published: May 2015

With the help of a Lie algebra of a reductive homogeneous space G/K, where G is a Lie group and K is a resulting isotropy group, we introduce a Lax pair for which an expanding (2+1)-dimensional integrable hierarchy is obtained by applying the binormial-residue representation (BRR) method, whose Hamiltonian structure is derived from the trace identity for deducing (2+1)-dimensional integrable hierarchies, which was proposed by Tu, et al. We further consider some reductions of the expanding integrable hierarchy obtained in the paper. The first reduction is just right the (2+1)-dimensional AKNS hierarchy, the second-type reduction reveals an integrable coupling of the (2+1)-dimensional AKNS equation (also called the Davey-Stewartson hierarchy), a kind of (2+1)-dimensional Schrödinger equation, which was once reobtained by Tu, Feng and Zhang. It is interesting that a new (2+1)-dimensional integrable nonlinear coupled equation is generated from the reduction of the part of the (2+1)-dimensional integrable coupling, which is further reduced to the standard (2+1)-dimensional diffusion equation along with a parameter. In addition, the well-known (1+1)-dimensional AKNS hierarchy, the (1+1)-dimensional nonlinear Schrödinger equation are all special cases of the (2+1)-dimensional expanding integrable hierarchy. Finally, we discuss a few discrete difference equations of the diffusion equation whose stabilities are analyzed by making use of the von Neumann condition and the Fourier method. Some numerical solutions of a special stationary initial value problem of the (2+1)-dimensional diffusion equation are obtained and the resulting convergence and estimation formula are investigated.
Modulational Instability of Spinor Condensates in an Optical Lattice*
Authors: Zheng Gong-Ping , Jian Wen-Tian , Yang Ling-Ling
Published: May 2015

We obtain analytically the static states and corresponding collective-excitation spectra of a quasi-one-dimensional spin-1 condensate modulated by a long-wavelength optical lattice in the weak lattice limit. It is demonstrated that both ferromagnetic and antiferromagnetic condensates may exhibit dynamical instability, which agree with the results with numerical simulation. In the homogeneous limit, our results reduce to the previous results for homogeneous spinor condensates, i.e., dynamical instability can occur only for ferromagnetic interaction and an antiferromagnetic condensate is always dynamically stable.
Optimal Force Mismatch for Fluctuation-Activated Transition in a System of Two Coupled Bistable Oscillators*
Authors: Chen Han-Shuang , Huang Feng , He Gang , Shen Chuan-Sheng , Hou Zhong-Huai
Published: May 2015

We study the fluctuation-activated transition process in a system of two coupled forced bistable oscillators with a mismatch σ in the force constants. As the coupling strength μ is increased, the transition pathway undergoes four stages changes from a two-step process with two candidate pathways to a mixture of a two-step pathway and a one-step pathway to a one-step process with also two candidate pathways and then to a one-step process with a single pathway. Interestingly, we find that the total transition rate depends nonmonotonically on σ in the weak coupling: a maximal rate appears in an intermediate magnitude of σ. Moreover, the rate also exhibits an unexpected maximum as a function of μ. The results are in an excellent agreement with our numerical simulations by forward flux sampling.
Fast Generation of GHZ States with Bose—Einstein Condensate in a Cavity*
Authors: Zhang Gang , Zhou Jian , Xue Zheng-Yuan
Published: May 2015

It is shown that strong coupling of Bose—Einstein condensates to an optical cavity can be realized experimentally. With an additional driven microwave field, we show that a highly nonlinear coupling among atoms in a Bose—Einstein condensate can be induced with the assistance of the cavity mode. With such interaction, we can investigate the generation of many body entangled states. In particularly, we show that multipartite entangled GHZ states can be obtained in such architecture with current available techniques.
Photo-Detached Electron Flux Distribution in a Gradient Electric Field*
Authors: Wang De-Hua , Tang Tian-Tian
Published: May 2015

This paper investigates the flux distributions of the electron photo-detached from H− ion localized in a gradient electric field. In contrast with the photodetachment in the uniform electric field [Phys. Rev. A 40 (1989) 4983], where only two electron trajectories interfere at each given point on a detector, for the photodetachment in a gradient electric field, the electrons waves can travel along multiple paths from the negative ion to a given point on the detector plane, which makes the electron flux distributions on the detector plane become much complex. Using the semi-classical theory, we put forward a formula for calculating the electron flux. Our calculation results suggest that the electron flux distributions on a given detector plane is not only related to the propagation time of the detached electron, but also related to the detached electron's energy. With the increase of the detached electron's energy, the oscillating region in the electron flux distributions becomes enlarged and the oscillating structure in the flux distributions becomes much more complicated. This study will guide future experiment research on the photodetachment microscopy of the negative ions in the presence of non-uniform external fields.
Nonautonomous Vortices in (2+1)-Dimensional Graded-Index Waveguide
Authors: Lai Xian-Jing , Cai Xiao-Ou , Zhang Jie-Fang
Published: May 2015

With the help of self-similarity transformation, we construct and study the nonautonomous vortices with different topological charges inside a planar graded-index nonlinear waveguide, analytically, and numerically. Although these vortices are approximate, they can reflect the real properties of self-similar optical beam during a short-term propagation. Existence of these autonomous vortices require delicate balances between the system parameters such as diffraction, nonlinearity, gain, and external potential. We are concerned with some special but interesting situations, and discussing the changes of the height, width, energy, and central position of the vortices as the increase of propagation distance. Moreover, we are also interested in the azimuthal modulational instability of the system, and comparing our prediction for the modulational instability growth rates to numerical results.
Nonlinear Exact Solutions of the 2-Dimensional Rotational Euler Equations for the Incompressible Fluid*
Authors: An Hong-Li , Yang Jin-Jing , Yuen Man-Wai
Published: May 2015

In this paper, the Clarkson-Kruskal direct approach is employed to investigate the exact solutions of the 2-dimensional rotational Euler equations for the incompressible fluid. The application of the method leads to a system of completely solvable ordinary differential equations. Several special cases are discussed and novel nonlinear exact solutions with respect to variables x and y are obtained. It is of interest to notice that the pressure p is obtained by the second kind of curvilinear integral and the coefficients of the nonlinear solutions are solitary wave type functions like tanh(kt/2) and sech (kt/2) due to the rotational parameter k ≠ 0. Such phenomenon never appear in the classical Euler equations wherein the Coriolis force arising from the gravity and Earth's rotation is ignored. Finally, illustrative numerical figures are attached to show the behaviors that the exact solutions may exhibit.
Absorption Spectra and Refractive Index Changes of an Exciton in a Core/Shell Quantum Dot
Authors: Xie Wen-Fang
Published: May 2015

The absorption spectra and the refractive index changes are calculated theoretically for an exciton in a core/shell quantum dot. The advantage of our methodology is that one can investigate the influence of the repulsive core by varying two parameters in the confinement potential. The dimensionality effect of exciton quantum dots on the optical absorptions has been studied. It has been found that in the same regime, the optical absorption intensities of excitons are much smaller for the core/shell quantum dots than for the two-dimensional quantum rings. The linear and the nonlinear optical absorption coefficients and refractive index changes have been examined with the change of the confinement potential. The results show that the optical absorptions and the refractive index changes are strongly affected by the repulsive core of core/shell quantum dots. Moreover, the calculated results also reveal that as the inner radius increases, the peak values of the absorption coefficients and the refractive index changes of an exciton will show the optical Aharonov-Bohm oscillation in core/shell quantum dots.
Calculation of Half-Metal, Debye and Curie Temperatures of Co2VAl Compound: First Principles Study*
Authors: Boochani Arash , Khosravi Heidar , Khodadadi Jabbar , Solaymani Shahram , Sarmazdeh Masoud Majidiyan , Mendi Rohollah Taghavi , Elahi Sayed Mohammad
Published: May 2015

By FP-LAPW calculations, the structural, elastic, Debye and Curie temperatures, electronic and magnetic properties of Co2 VAl are investigated. The results indicate that Ferromagnetic (FM) phase is more stable than Anti-Ferromagnetic (AFM) and Non-magnetic (NM) ones. In addition, C11-C12 > 0, C44 > 0, and B > 0 so Co2VAl is an elastically stable material with high Debye temperature. Also, the B/G ratio exhibits a ductility behavior. The relatively high Curie temperature provides it as a favorable material for spintronic application. It's electronic and magnetic properties are studied by GGA+U approach leading to a 100% spin polarization at Fermi level.
All-magnetic control of skyrmions in nanowires by a spin wave
Authors: Zhang Xichao , Ezawa Motohiko , Xiao Dun , Zhao G P , Liu Yaowen , Zhou Yan
Published: May 2015

Magnetic skyrmions are topologically protected nanoscale objects, which are promising building blocks for novel magnetic and spintronic devices. Here, we investigate the dynamics of a skyrmion driven by a spin wave in a magnetic nanowire. It is found that (i) the skyrmion is first accelerated and then decelerated exponentially; (ii) it can turn L-corners with both right and left turns; and (iii) it always turns left (right) when the skyrmion number is positive (negative) in the T- and Y-junctions. Our results will be the basis of skyrmionic devices driven by a spin wave.