bluuebunny/crossref_metadata_2025 huggingface dataset:
Fukui function and response function for nonlocal and fractional systems
Authors: Peng Degao , Yang Weitao
Published: May 2013

We present extensions to our previous work on Fukui functions and linear-response functions [W. Yang, A. J. Cohen, F. D. Proft, and P. Geerlings, J. Chem. Phys. 136, 144110 (2012)10.1063/1.3701562]. Viewed as energy derivatives with respect to the number of electrons and the external potential, all second-order derivatives (the linear-response function, the Fukui function, and the chemical hardness) are extended to fractional systems, and all third-order derivatives (the second-order response function, the Fukui response function, the dual descriptor, and the hyperhardness) for integer systems are also obtained. These analytical derivatives are verified by finite difference numerical derivatives. In the context of the exact linearity condition and the constancy condition, these analytical derivatives enrich greatly the information of the exact conditions on the energy functional through establishing real-space dependency. The introduction of an external nonlocal potential defines the nonlocal Fukui function and the nonlocal linear-response function. The nonlocal linear-response function so defined also provides the precise meaning for the time-dependent linear-response density-functional theory calculations with generalized Kohn-Sham functionals. These extensions will be useful to conceptual density-functional theory and density functional development.
Si isotopic structure of the infrared absorption of the fully hydrogenated vacancy in silicon
Authors: Clerjaud B. , Pajot B.
Published: May 2013

An infrared absorption spectrum consisting in three lines observed around 2223 cm−1 at liquid helium temperature characterizes a defect common in silicon crystals containing hydrogen. Several investigations of this spectrum have converged towards its assignment to a fully hydrogenated lattice vacancy defect V(Si–H)4. However, the fact that the ratios of the intensities of the three lines have been reported to be proportional to the natural abundances of the three silicon isotopes suggests that only one Si atom is involved in the defect, apparently contradicting the above assignment. In this paper, the spectroscopic investigation of this defect is revisited and the Si-related isotopic structures of V(Si–H)4 and V(Si–D)4 defects are modeled. It is shown that the near proportionalities observed between the intensities of these lines and the abundances of the Si isotopes are fortuitous. Our analysis of the isotope dependence of the 2223 cm−1 line finds the V(Si–H)4 model to be correct and that the model of a single interstitial Si atom complexed with H can be rejected. The investigation is extended to the analysis of tetra-hydrogenated vacancy trapped by a carbon atom.
Magnetic imaging with a Zernike-type phase plate in a transmission electron microscope
Authors: Pollard Shawn , Malac Marek , Beleggia Marco , Kawasaki Masahiro , Zhu Yimei
Published: May 2013

We demonstrate the use of a hole-free phase plate (HFPP) for magnetic imaging in transmission electron microscopy by mapping the domain structure in PrDyFeB samples. The HFPP, a Zernike-like imaging method, allows for detecting magnetic signals in-focus to correlate the sample crystal structure and defects with the local magnetization topography, and to evidence stray fields protruding from the sample. Experimental and simulated results are shown and are compared with conventional Fresnel (out-of-focus) images without a phase plate. A key advantage of HFPP imaging is that the technique is free from the reference wave distortion from long-range fields affecting electron holography.
Lie algebras and Hamiltonian structures of multi-component Ablowitz–Kaup–Newell–Segur hierarchy
Authors: Zhu Xiao-ying , Zhang Da-jun
Published: May 2013

Isospectral and non-isospectral hierarchies of multi-component Ablowitz–Kaup–Newell–Segur (AKNS) are obtained from a matrix spectral problem, then by means of the zero curvature representations of the isospectral flows {Km} and non-isospectral flows {σn}, we construct the symmetries and their algebraic structures for isospectral multi-component AKNS hierarchies, demonstrate the recursive operator L is a strong and hereditary symmetry for the isospectral hierarchy. We also derive that there are implectic operator θ and symplectic operator J such that L = θJ, and discuss the multi-Hamiltonian structures and the Liouville integrability of the isospectral hierarchies.
Velocity relaxation of a particle in a confined compressible fluid
Authors: Tatsumi Rei , Yamamoto Ryoichi
Published: May 2013

The velocity relaxation of an impulsively forced spherical particle in a fluid confined by two parallel plane walls is studied using a direct numerical simulation approach. During the relaxation process, the momentum of the particle is transmitted in the ambient fluid by viscous diffusion and sound wave propagation, and the fluid flow accompanied by each mechanism has a different character and affects the particle motion differently. Because of the bounding walls, viscous diffusion is hampered, and the accompanying shear flow is gradually diminished. However, the sound wave is repeatedly reflected and spreads diffusely. As a result, the particle motion is governed by the sound wave and backtracks differently in a bulk fluid. The time when the backtracking of the particle occurs changes non-monotonically with respect to the compressibility factor ɛ = ν/ac and is minimized at the characteristic compressibility factor. This factor depends on the wall spacing, and the dependence is different at small and large wall spacing regions based on the different mechanisms causing the backtracking.
Experimental study of the reactive processes in the gas phase K+ + i-C3H7Cl collisions: A comparison with Li and Na ions
Authors: Aguilar J. , Lucas J. M. , de Andrés J. , Albertí M. , Bassi D. , Aguilar A.
Published: May 2013

Reactive collisions between alkali ions (Li+, Na+, and K+) and halogenated hydrocarbon molecules have been studied recently in our research group. In this paper, we have reported on the K+ + i-C3H7Cl system in the 0.20–14.00 eV center-of-mass energy range using a radio frequency guided-ion beam apparatus developed in our laboratory. Aiming at increasing our knowledge about this kind of reactions, we compare our latest results for K+ with those obtained previously for Li+ and Na+. While the reaction channels are the same in all three cases, their energy profiles, reactivity, measured reactive cross-section energy dependences, and even their reaction mechanisms, differ widely. By comparing experimentally measured reactive cross-sections as a function of the collision energy with the ab initio calculations for the different potential energy surfaces, a qualitative interpretation of the dynamics of the three reactive systems is presented in the present work.
Theoretical model: Disorder and transport in amorphous nitrogenated carbon ribbons
Authors: Katkov Mikhail V. , Bhattacharyya Somnath
Published: May 2013

We investigate the origin of the nitrogen induced conductance cross-over in quasi-one dimensional disordered carbon structures through the analysis of resonant transmission features of electrons. The tight-binding model of the electronic structure of carbon was employed to calculate the transmission coefficients in the presence of structural disorder, which was controlled by changing the sp3 bond alternation as well as a hopping disorder parameter for the sp2 regions. The incorporation of nitrogen atoms in carbon networks was modeled as a combination of disorders which vary both in correlated and uncorrelated manners. By changing the bond alternation of sp3 − C sites correlated with the (incorporated) nitrogen site disorder, we establish the tunable characteristics of the resonance peaks inside the gap. Under proposed non-linear variation of the disorder parameter, the calculated resistance of the carbon structures was found to increase initially with the resonance energy followed by a decrease due to the appearance of resonant peaks close to the band edges. Resonant peaks associated with C and N sites in these structures show a conductance cross-over with the variation of nitrogen concentration in these structures. This work will be useful for developing nano-electronic devices based on nitrogen doped disordered graphene heterostructures.
A reactive magnetron sputtering route for attaining a controlled core-rim phase partitioning in Cu2O/CuO thin films with resistive switching potential
Authors: Ogwu A. A. , Darma T. H.
Published: May 2013

The achievement of a reproducible and controlled deposition of partitioned Cu2O/CuO thin films by techniques compatible with ULSI processing like reactive magnetron sputtering has been reported as an outstanding challenge in the literature. This phase partitioning underlies their performance as reversible resistive memory switching devices in advanced microelectronic applications of the future. They are currently fabricated by thermal oxidation and chemical methods. We have used a combination of an understanding from plasma chemistry, thermo-kinetics of ions, and rf power variation during deposition to successfully identify a processing window for preparing partitioned Cu2O/CuO films. The production of a core rich Cu2O and surface rich Cu2O/CuO mixture necessary for oxygen migration during resistive switching is confirmed by XRD peaks, Fourier transform infra red Cu (I)-O vibrational modes, XPS Cu 2P3/2 and O 1S peak fitting, and a comparison of satellite peak ratio's in Cu 2P3/2 fitted peaks. We are proposing based on the findings reported in this paper that an XPS satellite peak intensity(Is) to main peak intensity ratio (Im)  ≤ 0.45 as an indicator of a core rich Cu2O and surface rich Cu2O/CuO formation in our prepared films. CuO is solely responsible for the satellite peaks. This is explained on the basis that plasma dissociation of oxygen will be limited to the predominant formation of Cu2O under certain plasma deposition conditions we have identified in this paper, which also results in a core-rim phase partitioning. The deposited films also followed a Volmer-Weber columnar growth mode, which could facilitate oxygen vacancy migration and conductive filaments at the columnar interfaces. This is further confirmed by optical transmittance and band-gap measurements using spectrophotometry. This development is expected to impact on the early adoption of copper oxide based resistive memory electronic switching devices in advanced electronic devices of the future. The relative abundance of copper is another major complementary driver for the interest in copper oxide films.
Contact electrification by collision of homogenous particles
Authors: Xie L. , Li G. , Bao N. , Zhou Jùn
Published: May 2013

Contact electrification by collisions of homogenous particles is investigated by two-particle collision experiments, which reveals the relation between electrification and the diameter ratio and relative colliding velocity of the two particles. Then, based on researches reported by Grzybowski's research group, a statistical model to compute the net charge of electrified particle after a single collision and multiple collisions are established, respectively. The model shows the net charge carried by the electrified particles depends on the difference between the two surfaces’ areas involved in collision contact and gives results in good agreement with our experiment results.
Electrical characterisation and predictive simulation of defects induced by keV Si+ implantation in n-type Si
Authors: Nyamhere C. , Cristiano F. , Olivie F. , Essa Z. , Bedel-Pereira E. , Bolze D. , Yamamoto Y.
Published: May 2013

In this work, we focused on the analysis of implantation-induced defects, mainly small interstitial clusters (ICs) and {311} defects introduced in n-type Si after ion implantation using deep level transient spectroscopy (DLTS). Silicon ions (at 160 keV or 190 keV) of fluences ranging from (0.1–8.0) × 1013 cm−2 have been implanted into n-type Si and annealed at temperatures between 500 °C and 800 °C specifically to create small ICs or {311}s rod-like defects. In samples dominated by small ICs, DLTS spectra show prominent deep levels at Ec − 0.24 eV and Ec − 0.54 eV. After increasing the fluence and temperature, i.e., reducing the number of small ICs and forming {311} defects, the peak Ec − 0.54 eV is still dominant while other electron traps Ec − 0.26 eV and Ec − 0.46 eV are introduced. There were no observable deep levels in reference, non-implanted samples. The identity and origin of all these traps are interpreted in conjunction with recently developed predictive defect simulation models.
Three dimensional numerical study on the efficiency of a core-shell InGaN/GaN multiple quantum well nanowire light-emitting diodes
Authors: Li Chi-Kang , Yang Hung-Chih , Hsu Ta-Cheng , Shen Yu-Jiun , Liu Ai-Sen , Wu Yuh-Renn
Published: May 2013

This paper presents the findings of investigating core-shell multiple quantum well nanowire light-emitting diodes (LEDs). A fully self-consistent three dimensional model that solves Poisson and drift-diffusion equations was employed to investigate the current flow and quantum-confined stark effect. The core-shell nanowire LED showed a weaker droop effect than that of conventional planar LEDs because of a larger active area and stronger recombination in nonpolar quantum wells (QWs). The current spreading effect was examined to determine the carrier distribution at the sidewall of core-shell nanowire LEDs. The results revealed that a larger aspect ratio by increasing the nanowire height could increase the nonpolar-active area volume and reduce the droop effect at the same current density. Making the current spreading length exceed a greater nanowire height is critical for using the enhancement of nonpolar QWs effectively, when an appropriate transparent conducting layer might be necessary. In addition, this paper presents a discussion on the influences of the spacing between each nanowire on corresponding nanowire diameters.
Long electron spin coherence in ion-implanted GaN: The role of localization
Authors: Buß J. H. , Rudolph J. , Shvarkov S. , Hardtdegen H. , Wieck A. D. , Hägele D.
Published: May 2013

The impact of Ga and Au ion implantation on the electron spin dynamics in bulk wurtzite GaN is studied by time-resolved Kerr-rotation spectroscopy. The spin relaxation time increases strongly by up to a factor of 20 for increasing implantation doses. This drastic increase is caused by a transition from delocalized to localized electrons. We find a characteristic change in the magnetic field dependence of spin relaxation that can be used as a sensitive probe for the degree of localization.
Enhancing the energy of terahertz radiation from plasma produced by intense femtosecond laser pulses
Authors: Jahangiri Fazel , Hashida Masaki , Tokita Shigeki , Nagashima Takeshi , Hangyo Masanori , Sakabe Shuji
Published: May 2013

Terahertz (THz) radiation from atomic clusters illuminated by intense femtosecond laser pulses is investigated. By studying the angular distribution, polarization properties and energy dependence of THz waves, we aim to obtain a proper understanding of the mechanism of THz generation. The properties of THz waves measured in this study differ from those predicted by previously proposed mechanisms. To interpret these properties qualitatively, we propose that the radiation is generated by time-varying quadrupoles, which are produced by the ponderomotive force of the laser pulse.
Improving the accuracy of optical rotation measurement based on optical null methods by curve-fitting
Authors: Yang Zhenhao , Jia Hongzhi
Published: May 2013

An optical rotation measuring system using optical null methods is set up. The system is based on a step-motor rotating stage structure and a modulated laser, which both are controlled by digital signal processor. By introducing a curve-fitting method, the optical rotation angle is obtained from the step difference between the crossed positions in light signal curves with or without sample. The principle of this method is studied, and the system performance is investigated experimentally. We achieved an accuracy of the order of 10−3 degree in at least ±45° range, which is an improvement compared with the resolution of 0.01° for step-motor rotation stage.
Thermal conductivity of a ZnO nanowire/silica aerogel nanocomposite
Authors: Xie Jing , Frachioni Anthony , Williams D. S. , White B. E.
Published: May 2013

The thermal conductivity of 100 nm zinc oxide nanowires embedded in silica aerogel was measured using the 3ω method over a temperature range of 150 K to 300 K. Compared to 100 nm ZnO nanowires alone, the thermal conductivity of the nanocomposite was reduced by over an order of magnitude throughout this temperature range. We attribute this reduction to the scattering of ballistic phonons at the nanowire surface and the subsequent emission of and transport of energy by the scattered phonon into the silica aerogel, as predicted by the diffuse mismatch model.
Electron transport in nano-scaled piezoelectronic devices
Authors: Jiang Zhengping , Kuroda Marcelo A. , Tan Yaohua , Newns Dennis M. , Povolotskyi Michael , Boykin Timothy B. , Kubis Tillmann , Klimeck Gerhard , Martyna Glenn J.
Published: May 2013

The Piezoelectronic Transistor (PET) has been proposed as a post-CMOS device for fast, low-power switching. In this device, the piezoresistive channel is metalized via the expansion of a relaxor piezoelectric element to turn the device on. The mixed-valence compound SmSe is a good choice of PET channel material because of its isostructural pressure-induced continuous metal insulator transition, which is well characterized in bulk single crystals. Prediction and optimization of the performance of a realistic, nano-scaled PET based on SmSe requires the understanding of quantum confinement, tunneling, and the effect of metal interface. In this work, a computationally efficient empirical tight binding (ETB) model is developed for SmSe to study quantum transport in these systems and the scaling limit of PET channel lengths. Modulation of the SmSe band gap under pressure is successfully captured by ETB, and ballistic conductance shows orders of magnitude change under hydrostatic strain, supporting operability of the PET device at nanoscale.
Metamaterial lens made of fully printed resonant-type negative-refractive-index transmission lines
Authors: Xu He-Xiu , Wang Guang-Ming , Qing Qi Mei , Lv Yuan-Yuan , Gao Xi
Published: May 2013

We studied a well-resolved lens based on planar fully printed resonant-type negative-refractive-index transmission lines made of complementary split ring resonators. The lens goes beyond previous lens in terms of moderate loss and compactness. The focusing has been demonstrated by the circuit theory simulation and full-wave simulation and finally confirmed by the experiments, showing that that the lens is able to overcome the diffraction limit of 0.5 effective wavelengths and exhibits a super resolution as small as 0.348 effective wavelengths inside the lens. The superlens free of any lumped elements opens an easy and inexpensive avenue toward imaging devices with super performances.
A polar-drive shock-ignition design for the National Ignition Facility
Authors: Anderson K. S. , Betti R. , McKenty P. W. , Collins T. J. B. , Hohenberger M. , Theobald W. , Craxton R. S. , Delettrez J. A. , Lafon M. , Marozas J. A. , Nora R. , Skupsky S. , Shvydky A.
Published: May 2013

Shock ignition [R. Betti et al., Phys. Rev. Lett. 98, 155001 (2007)] is being pursued as a viable option to achieve ignition on the National Ignition Facility (NIF). Shock-ignition target designs use a high-intensity laser spike at the end of a low-adiabat assembly pulse to launch a spherically convergent strong shock to ignite the hot spot of an imploding capsule. A shock-ignition target design for the NIF is presented. One-dimensional simulations indicate an ignition threshold factor of 4.1 with a gain of 58. A polar-drive beam-pointing configuration for shock-ignition experiments on the NIF at 750 kJ is proposed. The capsule design is shown to be robust to the various one- and two-dimensional effects and nonuniformities anticipated on the NIF. The target is predicted to ignite with a gain of 38 when including all anticipated levels of nonuniformity and system uncertainty.
Tube transport of water vapor with condensation and desorption
Authors: Nordbo Annika , Kekäläinen Pekka , Siivola Erkki , Lehto Roope , Vesala Timo , Timonen Jussi
Published: May 2013

Attenuation and delay of active tracers in tube transport is an important current problem, but its full explanation is still lacking. To this end a model is introduced, where part of a tracer undergoes condensation and evaporation, treated as a diffusion-type process, in addition to Taylor dispersion. Condensation of water was verified by high-speed imaging, and the model solution fitted the breakthrough curves of laboratory measurements with pulses of water vapor of varying relative humidity. The model provides a transfer function whose performance was verified against field measurements.
Highly efficient inverted polymer solar cells with reduced graphene-oxide-zinc-oxide nanocomposites buffer layer
Authors: Woo Lee Hyun , Young Oh Jin , Il Lee Tae , Soon Jang Woo , Bum Yoo Young , Sang Chae Soo , Ho Park Jee , Min Myoung Jae , Moon Song Kie , Koo Baik Hong
Published: May 2013

In this study, we reported a 36% improvement in the performance of inverted solar cells as a result of increased short-circuit current (JSC) obtained using a composition of zinc oxide (ZnO) and reduced graphene oxide (RGO) as an n-type buffer layer. RGO-ZnO nanocomposites show higher electron conductivity than intrinsic ZnO; moreover, they show reduced contact resistance at the interface between the active layer and n-type buffer layer. These factors prevent carrier loss resulting from defects and recombinations in the device, thereby significantly increasing the JSC value for the device. Thus, an efficiency of 4.15% was achieved for inverted solar cells with a controlled RGO-ZnO nanocomposites layer.
First-principles study of edge-modified armchair graphene nanoribbons
Authors: Jippo Hideyuki , Ohfuchi Mari
Published: May 2013

We have used first-principles methods to study the geometries and electronic structures of hydrogen (H), fluorine (F), chlorine (Cl), and hydroxyl (OH) terminated armchair graphene nanoribbons (H-AGNRs, F-AGNRs, Cl-AGNRs, and OH-AGNRs) with ribbon widths N = 7 and 19. The most stable geometries of H-AGNRs have planar configurations, but those of F-, Cl-, and OH-AGNRs have rippled edges. The ripples stem from steric hindrances between neighboring pairs of terminal atoms or groups, and the ripples are strongly localized to the edges. The most stable termination occurs with F atoms owing to strong C-F bonds despite their rippled edge structures. The energy band gaps of F- and Cl-AGNRs are narrower than those of H-AGNRs. This is due to structural deformations rather than chemical effects. For OH-AGNRs, chemical interactions between neighboring OH groups further reduce the band gaps.
Far-field optical superlenses without metal
Authors: Regan Charles J. , Dominguez Daniel , Grave de Peralta Luis , Bernussi Ayrton A.
Published: May 2013

The spatial resolution in traditional optical microscopy is limited by diffraction. This prevents imaging of features with dimensions smaller than half of the wavelength (λ) of the illumination source. Superlenses have been recently proposed and demonstrated to overcome this issue. However, its implementation often involves complex sample fabrication and lossy metal layers. Alternatively, a superlens without metals can be realized using surface waves as the illumination source at the interface between two dielectrics, at the total internal reflection condition, where one of the dielectrics is doped with a fluorescent material. Non-scanning far-field images with resolution of ∼λ/5 and without the need of any post-processing or image reconstruction can be achieved with this approach.
Impact of UV/O3 treatment on solution-processed amorphous InGaZnO4 thin-film transistors
Authors: Umeda Kenichi , Miyasako Takaaki , Sugiyama Ayumu , Tanaka Atsushi , Suzuki Masayuki , Tokumitsu Eisuke , Shimoda Tatsuya
Published: May 2013

Ultraviolet–ozone (UV/O3) treatment was adopted to the fabrication of solution-processed amorphous In–Ga–Zn–O thin-film transistors (TFTs), with metal composition of In:Ga:Zn = 1:1:1 represented by InGaZnO4. By applying UV/O3 treatment In–Ga–Zn–O gel films, their condensation was notably enhanced through decomposition of organic- and hydrogen-based elements, which drastically improved the quality of the amorphous InGaZnO4 films. As a result, high TFT performance, with values of on/off ratio, 108; subthreshold swing, 150 mV/decade; threshold voltage, 9.2 V; and field-effect mobility, 5.1 cm2 V−1 s−1, was achieved.
Direct graphene synthesis on SiO2/Si substrate by ion implantation
Authors: Zhang R. , Wang Z. S. , Zhang Z. D. , Dai Z. G. , Wang L. L. , Li H. , Zhou L. , Shang Y. X. , He J. , Fu D. J. , Liu J. R.
Published: May 2013

We present results of few-layer graphene synthesis directly on SiO2/Si substrate by negative carbon ion implantation in Ni catalyst films on the top of SiO2/Si substrate. Negative carbon ions at 20 keV were implanted into Ni films with doses of (4–16) × 1015 cm−2. The implanted carbon atoms dissolved in Ni at an elevated temperature and diffused towards both sides of the Ni film. After annealing, graphene layers were observed on top of the Ni surface and on SiO2 beneath the Ni film. Formation of graphene layers directly on insulating substrates was achieved by etching the top Ni layer.
Spin-phonon coupling in Y2NiMnO6 double perovskite probed by Raman spectroscopy
Authors: Macedo Filho Raimundo Bezerra , Pedro Ayala Alejandro , William de Araujo Paschoal Carlos
Published: May 2013

Temperature-dependent Raman spectroscopy measurements in Y2NiMnO6 ceramics were performed in the 20 K–850 K range. A detailed analysis of the temperature dependence of the phonon energy of the oxygen octahedra stretching mode shows an anomalous softening below the Curie temperature. This effect was ascribed to a spin-phonon coupling, suggesting that the oxygen octahedra stretching vibrational mode stabilizes the magnetic interaction. The observed spin-phonon coupling is stronger than those reported in other Re2NiMnO6 double perovskites, suggesting that the rare earth ionic radius is not the unique parameter influencing the magnitude of this effect.
Configurational anisotropic spin waves in cross-shaped Ni80Fe20 nanoelements
Authors: Mahato B. K. , Rana B. , Mandal R. , Kumar D. , Barman S. , Fukuma Y. , Otani Y. , Barman A.
Published: May 2013

Optically induced spin waves in Ni80Fe20 (permalloy) cross-shaped nanoelements are studied by time-resolved magneto-optical Kerr effect microscope. A strong anisotropy in the spin wave modes are observed with the orientation angle (ϕ) of the in-plane bias magnetic field. As ϕ deviates from 0° a single resonant mode splits into a numbers of modes, while the powers of the higher frequency modes increase as ϕ increases from 0 to 45°. The lowest frequency mode shows a four-fold configurational anisotropy. The mode of a single cross remains unaffected by the magnetostatic interaction of the neighbouring elements for ϕ = 0°, while the effect increases with ϕ and becomes maximum at 45°, making these elements interesting candidates as building blocks for magnonic devices.
High-performance low-temperature solution-processed InGaZnO thin-film transistors via ultraviolet-ozone photo-annealing
Authors: Su Bo-Yuan , Chu Sheng-Yuan , Juang Yung-Der , Chen Han-Chang
Published: May 2013

Ultraviolet (UV)-ozone photo-annealing was applied to fabricate low-temperature high-performance solution-processed thin-film transistors (TFTs). With UV-ozone treatment at the optimal temperature of 300 °C, TFT devices showed an improved field-effect mobility of 1.73 cm2 V−1 s−1, a subthreshold slope (S) of 0.32 V dec−1, an on/off-current ratio greater than 1.3 × 107, and good operational bias-stress stability compared to those of InGaZnO TFT devices fabricated with only a conventional thermal-annealing process. The results of X-ray photoelectron spectroscopy and the maximum density of the surface states (Ns) confirm that the device improvement originates from reduced oxygen-related defects and improved electron trapping due to UV-ozone irradiation.
Transcriptome analyses and virus induced gene silencing identify genes in the Rpp4-mediated Asian soybean rust resistance pathway
Authors: Morales Aguida M. A. P. , O'Rourke Jamie A. , van de Mortel Martijn , Scheider Katherine T. , Bancroft Timothy J. , Borém Aluízio , Nelson Rex T. , Nettleton Dan , Baum Thomas J. , Shoemaker Randy C. , Frederick Reid D. , Abdelnoor Ricardo V. , Pedley Kerry F. , Whitham Steven A. , Graham Michelle A.
Published: May 2013

Rpp4 (Resistance to Phakopsora pachyrhizi 4) confers resistance to Phakopsora pachyrhizi Sydow, the causal agent of Asian soybean rust (ASR). By combining expression profiling and virus induced gene silencing (VIGS), we are developing a genetic framework for Rpp4-mediated resistance. We measured gene expression in mock-inoculated and P. pachyrhizi-infected leaves of resistant soybean accession PI459025B (Rpp4) and the susceptible cultivar (Williams 82) across a 12-day time course. Unexpectedly, two biphasic responses were identified. In the incompatible reaction, genes induced at 12 h after infection (hai) were not differentially expressed at 24 hai, but were induced at 72 hai. In contrast, genes repressed at 12 hai were not differentially expressed from 24 to 144 hai, but were repressed 216 hai and later. To differentiate between basal and resistance-gene (R-gene) mediated defence responses, we compared gene expression in Rpp4-silenced and empty vector-treated PI459025B plants 14 days after infection (dai) with P. pachyrhizi. This identified genes, including transcription factors, whose differential expression is dependent upon Rpp4. To identify differentially expressed genes conserved across multiple P. pachyrhizi resistance pathways, Rpp4 expression datasets were compared with microarray data previously generated for Rpp2 and Rpp3-mediated defence responses. Fourteen transcription factors common to all resistant and susceptible responses were identified, as well as fourteen transcription factors unique to R-gene-mediated resistance responses. These genes are targets for future P. pachyrhizi resistance research.
Delayed water loss and temperature rise in floral buds compared with leaves of Brassica rapa subjected to a transient water stress during reproductive development
Authors: Guo Yi Ming , Chen Sheng , Nelson Matthew N. , Cowling Wallace , Turner Neil C.
Published: May 2013

Leaf canopy temperature has been proposed as a rapid selection tool for drought tolerance among crop genotypes. However, floral bud temperature may be a better indicator of drought tolerance than leaf temperature in grain crops. In this study, we examined whether the floral bud and leaves of Brassica rapa L. had similar stomatal characteristics and showed similar water loss during a drying cycle. We also compared the leaf and bud temperatures when the plants were exposed to a 10-day transient water stress during reproductive development that affected flower development, increased flower abortion, increased pod abortion and reduced yield by an average of 85%. The water loss of detached leaves and floral buds showed that the stomata on the leaves closed before those of the floral buds as the leaf water potential decreased. Consistent with the water loss studies, the temperature of the intact bud showed a delayed increase during the drying process compared with the leaves. This suggested that floral bud temperature could be a useful indicator of the water status of the reproductive organs of B. rapa.
Simulation of N2O emissions and mitigation options for rainfed wheat cropping on a Vertosol in the subtropics
Authors: Li Yong , Wang Weijin , Reeves Steven , Dalal Ram C.
Published: May 2013

The Water and Nitrogen Management Model (WNMM) was applied to simulate nitrous oxide (N2O) emissions from a wheat-cropped Vertosol under long-term management of no-till, crop residue retention, and nitrogen (N) fertiliser application in southern Queensland, Australia, from July 2006 to June 2009. For the simulation study, eight treatments of combinations of conventional tillage (CT) or no-till (NT), stubble burning (SB) or stubble retention (SR), and N fertiliser application at nil (0N) or 90 (90N) kg N/ha.year were used. The results indicated that WNMM satisfactorily simulated the soil water content of the topsoil, mineral N content of the entire soil profile (0–1.5 m), and N2O emissions from the soil under the eight treatments, compared with the corresponding field measurements. For simulating daily N2O emissions from soil, WNMM performed best for the treatment CT-SB-90N (R2 = 0.48, P < 0.001; RMSE = 10.2 g N/ha.day) and worst for the treatment CT-SB-0N (R2 = 0.03, P = 0.174; RMSE = 1.2 g N/ha.day). WNMM predicted N2O emissions from the soil more accurately for the fertilised treatments (i.e. 90N v. 0N), and for the residue retained treatments (SR v. SB). To reduce N2O emissions from the no-till and fertilised treatments, three scenarios were examined: application of nitrification inhibitor, application of controlled-release fertiliser, and deep placement of liquid fertiliser (UAN32). Only the deep placement of UAN32 below the 35 cm depth was effective, and could reduce the N2O emissions from the soil by almost 40%.
Fire weather simulation skill by the Weather Research and Forecasting (WRF) model over south-east Australia from 1985 to 2009
Authors: Clarke Hamish , Evans Jason P. , Pitman Andrew J.
Published: May 2013

The fire weather of south-east Australia from 1985 to 2009 has been simulated using the Weather Research and Forecasting (WRF) model. The US National Oceanic and Atmospheric Administration Centers for Environmental Prediction and National Center for Atmospheric Research reanalysis supplied the lateral boundary conditions and initial conditions. The model simulated climate and the reanalysis were evaluated against station-based observations of the McArthur Forest Fire Danger Index (FFDI) using probability density function skill scores, annual cumulative FFDI and days per year with FFDI above 50. WRF simulated the main features of the FFDI distribution and its spatial variation, with an overall positive bias. Errors in average FFDI were caused mostly by errors in the ability of WRF to simulate relative humidity. In contrast, errors in extreme FFDI values were driven mainly by WRF errors in wind speed simulation. However, in both cases the quality of the observed data is difficult to ascertain. WRF run with 50-km grid spacing did not consistently improve upon the reanalysis statistics. Decreasing the grid spacing to 10km led to fire weather that was generally closer to observations than the reanalysis across the full range of evaluation metrics used here. This suggests it is a very useful tool for modelling fire weather over the entire landscape of south-east Australia.
Über Beweise und Beweisarten bei Wilhelm Ockham
Authors: Möllmann Heinz-Helmut
Published: May 2013

Die Arbeit versucht über drei, eigens gekennzeichnete und für Wilhelm Ockham (1285–1347) ausgewiesene Beweisarten (Induktion, Überredungsbeweis, Widerlegungsbeweis), die in einer Fülle von Beispielen dokumentiert werden, die Begründung seiner z. T. berüchtigten oder unverstandenen Thesen in ihrer Gesamtheit darzulegen. Sie zeigt, dass alle bekannten Stichworte und Schlüsselwörter bzw. Maximen wie notitia intuitiva, Omnipotenzprinzip, Ökonomieprinzip, daneben technische Begriffe wie consequentia, ratio, Kontradiktion, suppositio und ontologische, darunter forma, substantia, accidens, species, qualitas, quantitas, materia, mit diesen Argumentationsweisen in Zusammenhang stehen, genauer: von ihnen abhängen. Es ergibt sich, dass Ockham jeweils sehr spezielle und inhaltlich äußerst begrenzte Beweisziele verfolgt, deren Gesamtgeflecht in einer großen Struktur besteht, für die ein normaler logischer Beweismodus nicht mehr gelten kann. Die reale Geltung von Sätzen und Begriffen ist für Ockham unbestritten, doch bestreitet er, dass eine solche Annahme aus dem Verhältnis der Begriffe und danach der Aussagen abgeleitet werden könne. Er widerlegt die scholastischen Thesen, die das besagten.

There are three kinds of demonstration (induction, persuasion, and disproof) to be found in the writings of William Ockham (1285-1347) which are the base of his theses (opiniones) so often attacked or misunderstood in ancient and modern times. Famous key words such as intuitive cognition, the principles of omnipotence and economy, side by side with technical terms as consequentia, ratio, contradictio, suppositio, and ontological ones like forma, substantia, accidens, species, qualitas, quantitas, materia, and equally Ockham’s counter-arguments against Aristotelian and scholastic maxims essentially depend on these types of ratiocination. Ockham’s many proofs are especially ingenious and they generally have wide and unexpected consequences for reasoning. But the common pattern of deduction has been abandoned. While he acknowledges the validity of propositions and notions in the physical world Ockham denies that it can be proved as a statement for its own. Sometimes he even refutes it as a corollary of philosophical misconceptions.
Identification of Gender in Yellow Perch by External Morphology: Validation in Four Geographic Strains and Effects of Estradiol
Authors: Shepherd Brian S , Rees Christopher B , Sepulveda-Villet Osvaldo J , Palmquist Debra E , Binkowski Fred P
Published: May 2013

External morphological criteria that enable the rapid determination of gender have been developed for Yellow Perch Perca flavescens. Criteria are based upon (1) shape of the urogenital papilla (UGP), (2) size of the UGP relative to the anal (AN) opening, and (3) coloration of the UGP. In females, the UGP appeared (1) rounded at the anterior margin, (2) pointed at the posterior margin and had a V or U shape (crescent shaped in mature animals), (3) generally lacked reddish coloration, and (4) narrower relative to the AN. In males, the UGP (1) appeared circular or oval around the entire margin, (2) typically displayed reddish coloration, and (3) was generally wider relative to the AN. To verify accuracy of these criteria, gender was verified internally in perch of various sizes, sex, and maturity from four domesticated geographic strains (n = 1,389). For all perch tested, accuracy was 97.3% for both sexes, 98.8% for females, and 95.9% for males. To experimentally verify accuracy of these criteria, juvenile Yellow Perch (n = 913) were treated with dietary 17β-estradiol (E2; 15 mg/kg diet) or a control diet. Accuracy was 97.7% for control females and 95.1% for control males, which diminished to 63.9% for the E2-treated females and 57.6% for E2-treated males. We developed a gender identification algorithm that will enable sorting of sexes for many uses including (1) collection of broodstock by new aquaculture producers, (2) management of broodstocks for existing producers, (3) improved selection criteria for genetic selection programs, (4) studies on gender-specific differences in Yellow Perch physiology, and (5) the unharmed release of fish in field and aquaculture settings. Uncoupling of external UGP morphology from actual gender in E2-treated perch can enable producers and biologists to detect exposure to estrogenic compounds in areas where endocrine disruption is suspected.
A light-triggered protein secretion system
Authors: Chen Daniel , Gibson Emily S. , Kennedy Matthew J.
Published: May 2013

Optical control of protein interactions has emerged as a powerful experimental paradigm for manipulating and studying various cellular processes. Tools are now available for controlling a number of cellular functions, but some fundamental processes, such as protein secretion, have been difficult to engineer using current optical tools. Here we use UVR8, a plant photoreceptor protein that forms photolabile homodimers, to engineer the first light-triggered protein secretion system. UVR8 fusion proteins were conditionally sequestered in the endoplasmic reticulum, and a brief pulse of light triggered robust forward trafficking through the secretory pathway to the plasma membrane. UVR8 was not responsive to excitation light used to image cyan, green, or red fluorescent protein variants, allowing multicolor visualization of cellular markers and secreted protein cargo as it traverses the cellular secretory pathway. We implemented this novel tool in neurons to demonstrate restricted, local trafficking of secretory cargo near dendritic branch points.
Autophagosomal Syntaxin17-dependent lysosomal degradation maintains neuronal function in Drosophila
Authors: Takáts Szabolcs , Nagy Péter , Varga Ágnes , Pircs Karolina , Kárpáti Manuéla , Varga Kata , Kovács Attila L. , Hegedűs Krisztina , Juhász Gábor
Published: May 2013

During autophagy, phagophores capture portions of cytoplasm and form double-membrane autophagosomes to deliver cargo for lysosomal degradation. How autophagosomes gain competence to fuse with late endosomes and lysosomes is not known. In this paper, we show that Syntaxin17 is recruited to the outer membrane of autophagosomes to mediate fusion through its interactions with ubisnap (SNAP-29) and VAMP7 in Drosophila melanogaster. Loss of these genes results in accumulation of autophagosomes and a block of autolysosomal degradation during basal, starvation-induced, and developmental autophagy. Viable Syntaxin17 mutant adults show large-scale accumulation of autophagosomes in neurons, severe locomotion defects, and premature death. These mutant phenotypes cannot be rescued by neuron-specific inhibition of caspases, suggesting that caspase activation and cell death do not play a major role in brain dysfunction. Our findings reveal the molecular mechanism underlying autophagosomal fusion events and show that lysosomal degradation and recycling of sequestered autophagosome content is crucial to maintain proper functioning of the nervous system.
Route to destruction: Autophagosomes SNARE lysosomes
Authors: Krämer Helmut
Published: May 2013

Autophagy allows cells to encapsulate parts of their cytosol into unique double-membrane structures. These autophagosomes mature to fuse with lysosomes and deliver the enclosed contents for degradation. Three recent papers, including one by Takáts et al. (2013. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201211160), have taken different routes to discover a role for Syntaxin 17 in the maturation of autophagosomes.
Convergence rate of EM scheme for \normalfont𝑆𝐷𝐷𝐸𝑠
Authors: Bao Jianhai , Yuan Chenggui
Published: May 2013

In this paper we investigate the convergence rate of the Euler-Maruyama (EM) scheme for a class of stochastic differential delay equations, where the corresponding coefficients may be highly nonlinear with respect to the delay variables. In particular, we reveal that the convergence rate of the Euler-Maruyama scheme is

1
2

\frac {1}{2}

for the Brownian motion case, while we show that it is best to use the mean-square convergence for the pure-jump case and that the order of mean-square convergence is close to

1
2

\frac {1}{2}

.
Degenerations of K3 surfaces of degree two
Authors: Thompson Alan
Published: May 2013

We consider a semistable degeneration of K3 surfaces equipped with an effective divisor that defines a polarisation of degree two on a general fibre. We show that the map to the relative log canonical model of the degeneration maps every fibre to either a sextic hypersurface in

P

(
1
,
1
,
1
,
3
)

\mathbb {P}(1,1,1,3)

or a complete intersection of degree

(
2
,
6
)

(2,6)

in

P

(
1
,
1
,
1
,
2
,
3
)

\mathbb {P}(1,1,1,2,3)

. Furthermore, we find an explicit description of the hypersurfaces and complete intersections that can arise, thereby giving a full classification of the possible singular fibres.
Reconciling theories for metabolic scaling
Authors: Maino James L. , Kearney Michael R. , Nisbet Roger M. , Kooijman Sebastiaan A. L. M.
Published: May 2013

Metabolic theory specifies constraints on the metabolic organisation of individual organisms. These constraints have important implications for biological processes ranging from the scale of molecules all the way to the level of populations, communities and ecosystems, with their application to the latter emerging as the field of metabolic ecology. While ecologists continue to use individual metabolism to identify constraints in ecological processes, the topic of metabolic scaling remains controversial.

Much of the current interest and controversy in metabolic theory relates to recent ideas about the role of supply networks in constraining energy supply to cells. We show that an alternative explanation for physicochemical constraints on individual metabolism, as formalised by dynamic energy budget (DEB) theory, can contribute to the theoretical underpinning of metabolic ecology, while increasing coherence between intra‐ and interspecific scaling relationships.

In particular, we emphasise how the DEB theory considers constraints on the storage and use of assimilated nutrients and derive an equation for the scaling of metabolic rate for adult heterotrophs without relying on optimisation arguments or implying cellular nutrient supply limitation. Using realistic data on growth and reproduction from the literature, we parameterise the curve for respiration and compare the a priori prediction against a mammalian data set for respiration.

Because the DEB theory mechanism for metabolic scaling is based on the universal process of acquiring and using pools of stored metabolites (a basal feature of life), it applies to all organisms irrespective of the nature of metabolic transport to cells. Although the DEB mechanism does not necessarily contradict insight from transport‐based models, the mechanism offers an explanation for differences between the intra‐ and interspecific scaling of biological rates with mass, suggesting novel tests of the respective hypotheses.
Microbial community adaptation to quaternary ammonium biocides as revealed by metagenomics
Authors: Oh Seungdae , Tandukar Madan , Pavlostathis Spyros G. , Chain Patrick S. G. , Konstantinidis Konstantinos T.
Published: May 2013

Quaternary ammonium compounds (QACs) represent widely used cationic biocides that persist in natural environments. Although microbial degradation, sensitivity and resistance to QACs have been extensively documented, a quantitative understanding of how whole communities adapt to QAC exposure remain elusive. To gain insights into these issues, we exposed a microbial community from a contaminated river sediment to varied levels of benzalkonium chlorides (BACs, a family of QACs) for 3 years. Comparative metagenomic analysis showed that the BAC‐fed communities were dramatically decreased in phylogenetic diversity compared with the control (no BAC exposure), resulting presumably from BAC toxicity, and dominated by Pseudomonas species (> 50% of the total). Time‐course metagenomics revealed that community adaptation occurred primarily via selective enrichment of BAC‐degrading Pseudomonas populations, particularly P. nitroreducens, and secondarily via amino acid substitutions and horizontal transfer of a few selected genes in the Pseudomonas populations, including a gene encoding a PAS/PAC sensor protein and ring‐hydroxylating dioxygenase genes. P. nitroreducens isolates were reproducibly recoverable from communities after prolonged periods of no‐BAC exposure, suggesting that they are robust BAC‐degraders. Our study provides new insights into the mechanisms and tempo of microbial community adaptation to QAC exposure and has implications for treating QACs in biological engineered systems.