bluuebunny/crossref_metadata_2025 huggingface dataset:
Association amongst factors thought to be important by instructors in dental education and perceived effectiveness of these instructors by students
Authors: Chambers D. W. , Geissberger M. , Leknius C.
Published: December 2010

It is hypothesised that dental educators have perceptions of their roles as effective teachers. It is expected that subject matter expertise would be amongst the components of such personal philosophies of education, but it is unclear whether faculty member self‐perceptions carry over into student ratings of instructors’ effectiveness. A 20‐item survey of ‘Teaching Characteristics’ was completed by 86% of full‐time and 64% of the part‐time faculty members at the University of the Pacific. Respondents distributed 100 points amongst the descriptions of what makes an effective instructor. The responses were factor‐analysed, resulting in four general faculty ‘types’ that explained about 50% of the variance in ratings: expert, enthusiast, judicial and good soldier. Student ratings for the 2 years running up to the date of the survey administration were used to gauge student perceptions of instructor effectiveness. Faculty members who placed emphasis on expertise as key to being a good instructor received significantly lower ratings for teacher effectiveness from students than did other faculty members. Faculty members who conceived their roles as motivating students, explaining difficult concepts, displaying interest in the subject, showing compassion and caring, and being proactive tended to receive high ratings for teaching effectiveness from students.
Ectopic splenic nodules in the olive baboon (Papio cynocephalus anubis)
Authors: Jeneby M.M. , Langoi D. , Mwenda J.M. , D. Chai
Published: December 2010

Post‐mortem evaluation of a female sub‐adult olive baboon (Papio cynocephalus anubis) revealed a case of ectopic spleen anomaly. Three spherical masses characterized the spleen anomaly. The splenic nodules were located on the left upper quadrant of the stomach, at the distal end of the pancreas. The anterior nodule measures 1.2 cm, the middle nodule 1.9 cm and the posterior nodule 1.3 cm in diameter. Normal spleen was not observed in this case. All the three ectopic splenic nodules showed normal histological architecture. A case of ectopic splenic nodules in baboon is important in that the spleen malformation can readily be mistaken for a pathological process.
Macrophages recognize streptococci through bacterial single‐stranded RNA
Authors: Deshmukh Sachin D , Kremer Bernhard , Freudenberg Marina , Bauer Stefan , Golenbock Douglas T , Henneke Philipp
Published: December 2010

Group B streptococcus (GBS) is a leading cause of both neonatal sepsis and meningitis, two diseases that are characterized by inflammation. However, the manner in which GBS organisms are recognized by monocytes and macrophages is poorly understood. In this study, we report that the recognition of GBS and other Gram‐positive bacteria by macrophages and monocytes relies on bacterial single‐stranded RNA (ssRNA). ssRNA interacts with a signalling complex, which comprises the Toll‐like receptor adaptors MyD88 and UNC‐93B, but not the established MyD88‐dependent ssRNA sensors. The role of ssRNA in the recognition of Gram‐positive bacteria—leading to the induction of inflammatory cytokines—has potential implications for sepsis pathogenesis, diagnosis and treatment.
Models to study ancient host–pathogen interactions: lessons from Crete
Authors: Means Terry K , Aballay Alejandro
Published: December 2010

The first International Conference on Model Hosts was the first of its kind and gathered together international experts who are using range of hosts as models of infection, including worms, insects, mice, fish, rats, humans, squids, pigs, monkeys, protozoa, amoebae and ticks.
How do economic crises impact firm boundaries?
Authors: Foss Kirsten
Published: December 2010

How economic crises impact the boundaries of firms has been offered virtually no attention in the literature on the theory of the firm. I review the best‐known theories of the firm and identify the variables that matter for the explanation of firm boundaries. I then examine how an economic crisis may impact these variables and change efficient firm boundaries. The various theories of the firm have difficulties explaining how firms efficiently adapt their boundaries to such prominent characteristics of economic crisis as declining demand and increased costs of external finance. However, all these theories stress uncertainty as an antecedent of firm organization, and as uncertainty is also an important characteristic of an economic crisis I examine how uncertainty is allowed to play out in the various theories in order to identify what predictions we can derive from the theory regarding changes in efficient firm boundaries as consequence of changes in uncertainty. The analysis suggests that we need to be more precise in describing the nature of the uncertainty that is assumed in the various theories. Moreover, allowing for changes in levels of uncertainty requires that we take the processes of boundary changes into account in the theory of firm boundaries.
Electron collisions in the trapped gyro-Landau fluid transport model
Authors: Staebler G. M. , Kinsey J. E.
Published: December 2010

Accurately modeling electron collisions in the trapped gyro-Landau fluid (TGLF) equations has been a major challenge. Insights gained from numerically solving the gyrokinetic equation have lead to a significant improvement of the low order TGLF model. The theoretical motivation and verification of this model with the velocity-space gyrokinetic code GYRO [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] will be presented. The improvement in the fidelity of TGLF to GYRO is shown to also lead to better prediction of experimental temperature profiles by TGLF for a dedicated collision frequency scan.
Two-dimensional photonic crystal for absorption enhancement in hydrogenated amorphous silicon thin film solar cells
Authors: Gomard Guillaume , Drouard Emmanuel , Letartre Xavier , Meng Xianqin , Kaminski Anne , Fave Alain , Lemiti Mustapha , Garcia-Caurel Enric , Seassal Christian
Published: December 2010

We propose a photovoltaic solar cell design based on a 100 nm thick absorbing layer made of hydrogenated amorphous silicon and patterned as a two-dimensional planar photonic crystal (PPC). After scanning the parameters of the PPC within the patterned cell, optical simulations performed on the best configuration obtained reveal that a relative increase in the integrated absorption inside the active layer of 28% can be expected between 300 and 720 nm compared to an equivalent but nonpatterned cell under normal incidence. Besides, this integrated absorption is found to be robust toward the angle of incidence. Incident light is efficiently coupled to leaky mode resonances of the PPC provided an appropriated tuning of its parameters. The effects of the reflectance of the back contact coupled to a conductive optical spacer on the absorption are also discussed.
Electronic structure and the glass transition in pnictide and chalcogenide semiconductor alloys. II. The intrinsic electronic midgap states
Authors: Zhugayevych Andriy , Lubchenko Vassiliy
Published: December 2010

We propose a structural model that treats in a unified fashion both the atomic motions and electronic excitations in quenched melts of pnictide and chalcogenide semiconductors. In Part I [A. Zhugayevych and V. Lubchenko, J. Chem. Phys. 133, 234503 (2010)], we argued these quenched melts represent aperiodic ppσ-networks that are highly stable and, at the same time, structurally degenerate. These networks are characterized by a continuous range of coordination. Here we present a systematic way to classify these types of coordination in terms of discrete coordination defects in a parent structure defined on a simple cubic lattice. We identify the lowest energy coordination defects with the intrinsic midgap electronic states in semiconductor glasses, which were argued earlier to cause many of the unique optoelectronic anomalies in these materials. In addition, these coordination defects are mobile and correspond to the transition state configurations during the activated transport above the glass transition. The presence of the coordination defects may account for the puzzling discrepancy between the kinetic and thermodynamic fragility in chalcogenides. Finally, the proposed model recovers as limiting cases several popular types of bonding patterns proposed earlier including: valence-alternation pairs, hypervalent configurations, and homopolar bonds in heteropolar compounds.
Ferrule-top atomic force microscope
Authors: Chavan D. , Gruca G. , de Man S. , Slaman M. , Rector J. H. , Heeck K. , Iannuzzi D.
Published: December 2010

Ferrule-top cantilevers are a new generation of all-optical miniaturized devices for utilization in liquids, harsh environments, and small volumes [G. Gruca et al., Meas. Sci. Technol. 21, 094033 (2010)]. They are obtained by carving the end of a ferruled fiber in the form of a mechanical beam. Light coupled from the opposite side of the fiber allows detection of cantilever deflections. In this paper, we demonstrate that ferrule-top cantilevers can be used to develop ultra compact AFMs for contact mode imaging in air and in liquids with sensitivity comparable to that of commercial AFMs. The probes do not require any alignment procedure and are easy to handle, favoring applications also outside research laboratories.
Atomistic modeling of lattice frame effects on laser-induced dislocation behaviors in nanopore mending processes
Authors: Huang Pei-Hsing , Lai Hsin-Yi
Published: December 2010

In recent years, the femtosecond laser technique has emerged as an effective tool for defect mending, especially for fault repairs of the conducting wire in three-dimensional integrated circuits. However, the nanodefect mending mechanism subjected to photothermal and mechanical stress introduced by ultrafast laser dynamics is still not well understood so far. In this paper, the microscopic dislocation behaviors of the lattice mending of metallic nanopore defects induced by femtosecond laser is presented using a modified continuum-atomistic modeling approach and the quantitative dislocation-based analysis. Two different cases of lattice frame effects are elaborated to characterize the dislocation behaviors and the nanopore mending mechanisms. The lattice frame is found to possess a direct effect on controlling the mechanisms of nucleation and growth of dislocation during laser interaction with metallic microdefects. The nanopore defect with a symmetric lattice frame is observed to form a prismaticlike slip structure around the pore region, and the dislocation loop consequently expands along its glide-prism plane. The growth of the loops continues even after they are fully mended to form sessile junctions by creating a local anisotropic hardening structure. On the other hand, the nanopore defect of an asymmetric lattice frame induces drastically irregular lattice glides, forming a tight network of junction loops around the mended area. It was found that the fast shock wave enhanced by the stress concentration factor around the pore that enabled a cooperative movement of sheets of atoms around the pore. This particular mechanism causes a rapid mending of the hole with a metastable lattice structure. The heterogeneous reaction dynamics of dislocation nucleation on the pore defect surface is analyzed in detail in this study. The photomechanical and thermally-activated plastic flow of mending processes is also clearly elucidated. The results provide vital insights into better dynamic behavior characterization of how the ultrafast laser interacts with metallic microdefects.
Resistances for heat and mass transfer through a liquid–vapor interface in a binary mixture
Authors: Glavatskiy K. S. , Bedeaux D.
Published: December 2010

In this paper we calculate the interfacial resistances to heat and mass transfer through a liquid–vapor interface in a binary mixture. We use two methods, the direct calculation from the actual nonequilibrium solution and integral relations, derived earlier. We verify, that integral relations, being a relatively faster and cheaper method, indeed gives the same results as the direct processing of a nonequilibrium solution. Furthermore we compare the absolute values of the interfacial resistances with the ones obtained from kinetic theory. Matching the diagonal resistances for the binary mixture we find that kinetic theory underestimates the cross coefficients. The heat of transfer is, as a consequence, correspondingly larger.
Communication: Hybrid ensembles for improved force matching
Authors: Wang Lee-Ping , Van Voorhis Troy
Published: December 2010

Force matching is a method for parameterizing empirical potentials in which the empirical parameters are fitted to a reference potential energy surface (PES). Typically, training data are sampled from a canonical ensemble generated with either the empirical potential or the reference PES. In this Communication, we show that sampling from either ensemble risks excluding critical regions of configuration space, leading to fitted potentials that deviate significantly from the reference PES. We present a hybrid ensemble which combines the Boltzmann probabilities of both potential surfaces into the fitting procedure, and we demonstrate that this technique improves the quality and stability of empirical potentials.
Wave functions and energy spectra for the hydrogenic atom in $\mathbb {R}^3 \times \mathcal {M}$ R3×M
Authors: Van Gorder Robert A.
Published: December 2010

We consider the hydrogenic atom in a space of the form \documentclass[12pt]{minimal}\begin{document}$\mathbb {R}^3 \times \mathcal {M}$\end{document}R3×M, where \documentclass[12pt]{minimal}\begin{document}$\mathcal {M}$\end{document}M may be a generalized manifold obeying certain properties. We separate the solution to the governing time-independent Schrödinger equation into a component over \documentclass[12pt]{minimal}\begin{document}$\mathbb {R}^3$\end{document}R3 and a component over \documentclass[12pt]{minimal}\begin{document}$\mathcal {M}$\end{document}M. Upon obtaining a solution to the relevant eigenvalue problems, we recover both the wave functions and energy spectrum for the hydrogenic atom over \documentclass[12pt]{minimal}\begin{document}$\mathbb {R}^3 \times \mathcal {M}$\end{document}R3×M. We consider some specific examples of \documentclass[12pt]{minimal}\begin{document}$\mathcal {M}$\end{document}M, including the fairly simple D-dimensional torus \documentclass[12pt]{minimal}\begin{document}$T^D$\end{document}TD and the more complicated Kähler conifold \documentclass[12pt]{minimal}\begin{document}$\mathcal {K}$\end{document}K in order to illustrate the method. In the examples considered, we see that the corrections to the standard energy spectrum for the hydrogen atom due to the addition of higher dimensions scale as a constant times \documentclass[12pt]{minimal}\begin{document}$1/L^2$\end{document}1/L2, where L denotes the size of the additional dimensions. Thus, under the assumption of small compact extra dimensions, even the first energy corrections to the standard spectrum will be quite large.
Transmission and total reflection of subhertz electromagnetic waves at the earth-atmosphere interface
Authors: Shiozawa Toshiyuki
Published: December 2010

For the purpose of providing for a theoretical background for the study of electromagnetic fields generated by precursory effects of earthquakes, the problem of transmission and total reflection at the earth-atmosphere interface is investigated in detail for a subhertz plane electromagnetic wave incident from the earth’s crust. The term “subhertz” means “below 1 Hz.” First, for the special case of normal incidence, the overall power transmission coefficient at the earth–atmosphere interface is found to take a maximum value at a definite frequency f0 which is inversely proportional to the square of the depth of a virtual hypocenter. A typical value of f0 falls around 0.01 Hz. For oblique incidence as well, this feature of the overall power transmission coefficient is retained except in the vicinity of the critical angle of incidence for the H-wave. At the critical angle of incidence, the power flow carried by a surface wave along the interface becomes anomalously large for the H-wave. However, over a wide range of angles of incidence greater than the critical angle, the power flow carried by the E-wave exceeds that carried by the H-wave by orders of magnitude. Finally, the energy conservation relations for the incident, reflected, and transmitted waves at the earth-atmosphere interface are discussed. For an incident wave coming from the earth’s crust, the interactive power between the incident and reflected waves plays a crucial role for the conservation of energy at the interface.
High-level incorporation of antimony in germanium by laser annealing
Authors: Bruno E. , Scapellato G. G. , Bisognin G. , Carria E. , Romano L. , Carnera A. , Priolo F.
Published: December 2010

In this work we investigate pulse laser annealing as an alternative approach to reach high-level incorporation of Sb in substitutional location in crystalline germanium. Laser irradiation is demonstrated to recover also those structural defects, like honeycomb structures, that form during high-fluence heavy-ion implantations in Ge and that cannot be eliminated by conventional thermal treatments. Indeed, concentrations of substitutional Sb higher than 1×1021 at./cm3 have been obtained, well above the solid solubility of Sb in Ge. The strain induced on the Ge host lattice is also investigated, evidencing that the obtained Sb doped Ge layer is pseudomorphic to the Ge substrate while positively strained by the substitutional Sb atoms present within the Ge matrix. The kinetics of this Sb-rich Ge alloy phase is finally investigated, showing that most of Sb goes out of lattice with increasing the annealing temperature up to 488 °C, leading to a decrease in the related lattice deformation. These results are very relevant for the future high-mobility channel technology.
Communication: Direct observation of a hydrophobic bond in loop closure of a capped (–OCH $_2$2CH $_2$2–) $_n$n oligomer in water
Authors: Chaudhari Mangesh I. , Pratt Lawrence R. , Paulaitis Michael E.
Published: December 2010

The small r variation of the probability density P(r) for end-to-end separations of a –CH \documentclass[12pt]{minimal}\begin{document}$_2$\end{document}2CH \documentclass[12pt]{minimal}\begin{document}$_3$\end{document}3 capped (–OCH \documentclass[12pt]{minimal}\begin{document}$_2$\end{document}2CH \documentclass[12pt]{minimal}\begin{document}$_2$\end{document}2–) \documentclass[12pt]{minimal}\begin{document}$_n$\end{document}n oligomer in water is computed to be closely similar to the CH \documentclass[12pt]{minimal}\begin{document}$_4\cdots$\end{document}4⋯ CH \documentclass[12pt]{minimal}\begin{document}$_4$\end{document}4 potential of mean force under the same circumstances. Since the aqueous solution CH \documentclass[12pt]{minimal}\begin{document}$_4\cdots$\end{document}4⋯ CH \documentclass[12pt]{minimal}\begin{document}$_4$\end{document}4 potential of mean force is the natural physical definition of a primitive hydrophobic bond, the present result identifies an experimentally accessible circumstance for direct observation of a hydrophobic bond which has not been observed previously because of the low solubility of CH \documentclass[12pt]{minimal}\begin{document}$_4$\end{document}4 in water. The physical picture is that the soluble chain molecules carry the capping groups into aqueous solution, and permits them to find one another with reasonable frequency. Comparison with the corresponding results without the solvent shows that hydration of the solute oxygen atoms swells the chain molecule globule. This supports the view that the chain molecule globule might have a secondary effect on the hydrophobic interaction that is of first interest here. The volume of the chain molecule globule is important for comparing the probabilities with and without solvent because it characterizes the local concentration of capping groups. Study of other capping groups to enable x-ray and neutron diffraction measurements of P(r) is discussed.
Magnetoencephalography with a two-color pump-probe, fiber-coupled atomic magnetometer
Authors: Johnson Cort , Schwindt Peter D. D. , Weisend Michael
Published: December 2010

The authors have detected magnetic fields from the human brain with a compact, fiber-coupled rubidium spin-exchange-relaxation-free magnetometer. Optical pumping is performed on the D1 transition and Faraday rotation is measured on the D2 transition. The beams share an optical axis, with dichroic optics preparing beam polarizations appropriately. A sensitivity of <5 fT/Hz is achieved. Evoked responses resulting from median nerve and auditory stimulation were recorded with the atomic magnetometer. Recordings were validated by comparison with those taken by a commercial magnetoencephalography system. The design is amenable to arraying sensors around the head, providing a framework for noncryogenic, whole-head magnetoencephalography.
Wigner quantization of some one-dimensional Hamiltonians
Authors: Regniers G. , Van der Jeugt J.
Published: December 2010

Recently, several papers have been dedicated to the Wigner quantization of different Hamiltonians. In these examples, many interesting mathematical and physical properties have been shown. Among those we have the ubiquitous relation with Lie superalgebras and their representations. In this paper, we study two one-dimensional Hamiltonians for which the Wigner quantization is related with the orthosymplectic Lie superalgebra \documentclass[12pt]{minimal}\begin{document}$\mathfrak {osp}(1|2)$\end{document}osp(1|2). One of them, the Hamiltonian \documentclass[12pt]{minimal}\begin{document}$\hat{H} = \hat{x} \hat{p}$\end{document}Ĥ=x̂p̂, is popular due to its connection with the Riemann zeros, discovered by Berry and Keating on the one hand and Connes on the other. The Hamiltonian of the free particle, \documentclass[12pt]{minimal}\begin{document}$\hat{H}_f = \hat{p}^2/2$\end{document}Ĥf=p̂2/2, is the second Hamiltonian we will examine. Wigner quantization introduces an extra representation parameter for both of these Hamiltonians. Canonical quantization is recovered by restricting to a specific representation of the Lie superalgebra \documentclass[12pt]{minimal}\begin{document}$\mathfrak {osp}(1|2)$\end{document}osp(1|2).
Green function of the inhomogeneous Helmholtz equation with nonuniform refraction index, using quaternion analysis
Authors: Fathi S. M. Saberi
Published: December 2010

In this paper we first show in the framework of quaternion analysis how the fundamental solutions of the Dirac operators with vector potential can be obtained. Then, we use the obtained results to present a derivation of the exact analytic Green function for the Helmholtz equation, i.e., \documentclass[12pt]{minimal}\begin{document}$(\triangle +|\mathbf {a}(\mathbf {x})|^2) G_0(\mathbf {x})=\delta (\mathbf {x})$\end{document}(▵+|a(x)|2)G0(x)=δ(x), for the case \documentclass[12pt]{minimal}\begin{document}$\mathbf {a}(\mathbf {x})$\end{document}a(x) is a monogenic (analytic) vector potential.
Concentration dependence of magnetic moment in Ni50-xCoxMn50-yZy (Z=In,Sn) Heusler alloys
Authors: Ito W. , Xu X. , Umetsu R. Y. , Kanomata T. , Ishida K. , Kainuma R.
Published: December 2010

The concentration dependence of magnetic properties in the austenite phase of NiCoMnIn and NiCoMnSn Heusler alloys was systematically investigated by the magnetization measurements. The TC for Ni(50-x)CoxMn(50-y)Sny alloys linearly increases with increasing the Co content and fixed Sn content. Although showing a concave curve for Ni50Mn(50-y)Sny ternary alloys, the Sn content-dependence of magnetic moment per formula unit changes from the concave curve to a straight line when Co is substituted for Ni. On the other hand, the In content-dependence of the magnetic moment for Ni45Co5Mn(50-y)Iny alloys is perfectly linear as is that in the Ni50Mn(50-y)Iny ternary alloys.
Photon antibunching and magnetospectroscopy of a single fluorine donor in ZnSe
Authors: De Greve K. , Clark S. M. , Sleiter D. , Sanaka K. , Ladd T. D. , Panfilova M. , Pawlis A. , Lischka K. , Yamamoto Y.
Published: December 2010

We report on the optical investigation of single electron spins bound to fluorine donor impurities in ZnSe. Measurements of photon antibunching confirm the presence of single, isolated optical emitters, and magneto-optical studies are consistent with the presence of an exciton bound to the spin-impurity complex. The isolation of this single-donor-bound-exciton complex and its potential homogeneity offer promising prospects for a scalable semiconductor qubit with an optical interface.
Superlatticelike dielectric as a thermal insulator for phase-change random access memory
Authors: Loke Desmond , Shi Luping , Wang Weijie , Zhao Rong , Ng Lung-Tat , Lim Kian-Guan , Yang Hongxin , Chong Tow-Chong , Yeo Yee-Chia
Published: December 2010

Superlatticelike (SLL) dielectric comprising of Ge2Sb2Te5 and SiO2 was employed to reduce the power and increase the speed of phase-change random access memories (PCRAMs). In this study, we found that PCRAM cells with SLL dielectric require lower currents and shorter pulse-widths to switch compared to the cells with SiO2 dielectric. As the thickness of the SLL period reduces, the power and speed of the cells improved further due to the better thermal confinement of the SLL dielectric. Fast phase-change in 5 ns was observed in large cells of 1 μm, showing the effectiveness of SLL dielectric for advanced memory applications.
ZnO random laser diode arrays for stable single-mode operation at high power
Authors: Liang H. K. , Yu S. F. , Yang H. Y.
Published: December 2010

An array of highly disordered i-ZnO:Al(3%) random cavities, which have 1 μm width, 150 nm thickness, and 2 mm length, is sandwiched between n-ZnO:Al(5%) and p-GaN/sapphire substrate to form an array of heterojunctions. The random cavities, which are electrically isolated and optically coupled with the adjacent random cavities, are laterally separated by a 1 μm wide Al2O3 dielectric insulator. Stable single-mode operation is observed from the laser diode array under high electrical pumping (i.e., >6×threshold current) at room temperature.
Defects responsible for the Fermi level pinning in n+ poly-Si/HfO2 gate stacks
Authors: Ryu Byungki , Chang K. J.
Published: December 2010

Based on density functional calculations, we propose a defect model that can explain flat band voltage shifts, especially in n+ poly-Si/HfO2 gate stacks. For two interface structures, with Si electrodes on top of crystalline and amorphous HfO2, we find the formation of O-vacancies at the interface, which exhibit weak Si–Si dimer bonds and low formation energies, very different from those in the oxide. Due to weak dimer bonds, charge trap levels lie near the Si conduction band edge, leading to the Fermi level pinning and flat band voltage shifts in n+ poly-Si gate electrodes.
Molecular n-type doping for air-stable electron transport in vacuum-processed n-channel organic transistors
Authors: Oh Joon Hak , Wei Peng , Bao Zhenan
Published: December 2010

The effects of n-type doping on the air-stability of vacuum-processed n-channel organic transistors have been investigated using perylene diimides and pyronin B as the active layer and dopant, respectively. Systematic studies on the influence of doping location revealed the n-type doping of bulk active layer or channel region significantly improves air-stability by compensating for the trapped electrons with the donated mobile electrons. Although n-type doping at the electrode contact could readily turn on the devices, it could not confer air-stable electron transport. The described approach would open up opportunities to enable and improve the stability of n-channel organic transistors in air.
Pseudoelastic stacking fault and deformation twinning in nanocrystalline Ni
Authors: Li B. Q. , Sui M. L. , Mao S. X.
Published: December 2010

It is usually believed that the partial dislocation and deformation twin are the results of permanent plasticity in materials. Here, we present in situ atomic-scale observation of reversible stacking fault and deformation twin during loading and unloading in nanocrystalline Ni under high-resolution transmission electron microscopy. The high propensity for the reversibility of the stacking fault and deformation twin is due to the high stacking fault force and small grain size, and will provide an understanding at atomistic scale on the nature of the deformation in nanocrystalline materials.
Radio frequency electrical transduction of graphene mechanical resonators
Authors: Xu Yuehang , Chen Changyao , Deshpande Vikram V. , DiRenno Frank A. , Gondarenko Alexander , Heinz David B. , Liu Shuaimin , Kim Philip , Hone James
Published: December 2010

We report radio frequency (rf) electrical readout of graphene mechanical resonators. The mechanical motion is actuated and detected directly by using a vector network analyzer, employing a local gate to minimize parasitic capacitance. A resist-free doubly clamped sample with resonant frequency ∼34 MHz, quality factor ∼10 000 at 77 K, and signal-to-background ratio of over 20 dB is demonstrated. In addition to being over two orders of magnitude faster than the electrical rf mixing method, this technique paves the way for use of graphene in rf devices such as filters and oscillators.
Quantum pumping in graphene with a perpendicular magnetic field
Authors: Tiwari Rakesh P. , Blaauboer M.
Published: December 2010

We consider quantum pumping of Dirac fermions in a monolayer of graphene in the presence of a perpendicular magnetic field in the central pumping region. The two external pump parameters are electrical voltages applied to the graphene sheet on either side of the pumping region. We analyze this pump within scattering matrix formalism and calculate both pumped charge and spin currents. The predicted charge currents are of the order of 1000 nA, which is readily observable using current technology.
Natural 15N/14N isotope composition in C3 leaves: are enzymatic isotope effects informative for predicting the 15N-abundance in key metabolites?
Authors: Tcherkez Guillaume
Published: December 2010

Although nitrogen isotopes are viewed as important tools for understanding plant N acquisition and allocation, the current interpretation of natural 15N-abundances (δ15N values) is often impaired by substantial variability among individuals or between species. Such variability is likely to stem from the fact that 15N-abundance of assimilated N is not preserved during N metabolism and redistribution within the plant; that is, 14N/15N isotope effects associated with N metabolic reactions are certainly responsible for isotopic shifts between organic-N (amino acids) and absorbed inorganic N (nitrate). Therefore, to gain insights into the metabolic origin of 15N-abundance in plants, the present paper reviews enzymatic isotope effects and integrates them into a metabolic model at the leaf level. Using simple steady-state equations which satisfactorily predict the δ15N value of amino acids, it is shown that the sensitivity of δ15N values to both photorespiratory and N-input (reduction by nitrate reductase) rates is quite high. In other words, the variability in δ15N values observed in nature might originate from subtle changes in metabolic fluxes or environment-driven effects, such as stomatal closure that in turn changes v0, the Rubisco-catalysed oxygenation rate.
The hyp-1 gene is not a limiting factor for hypericin biosynthesis in the genus Hypericum
Authors: Košuth Ján , Smelcerovic Andrija , Borsch Thomas , Zuehlke Sebastian , Karppinen Katja , Spiteller Michael , Hohtola Anja , Čellárová Eva
Published: December 2010

Biosynthesis of the hypericins that accumulate in the dark glands of some members of the genus Hypericum is poorly understood. The gene named hyp-1, isolated from Hypericum perforatum L. has been proposed as playing an important role in the final steps of hypericin biosynthesis. To study the role of this candidate gene in relation to the production of hypericins, the expression of this gene was studied in 15 Hypericum species with varying ability to synthesise hypericin. While the accumulation of hypericins and emodin, an intermediate in the respective pathway, was associated with the dark glands in the hypericin-producing species, the hyp-1 gene was expressed in all studied species regardless of whether hypericins and emodin were detected in the plants. The coding sequences of hyp-1 cDNA were isolated from all species and showed more than 86% similarity to each other. Although, in general, an increased level of the hyp-1 gene transcript was detected in hypericin-producing species, several of the hypericin-lacking species expressed comparable levels as well. Our results question the role of the hyp-1 gene product as a key enzyme responsible for biosynthesis of hypericins in the genus Hypericum. The function of the hyp-1 gene may not be restricted to hypericin biosynthesis only, or some additional factors are necessary for completion of hypericin biosynthesis.
Promiscuous mating in feral pigs (Sus scrofa) from Texas, USA
Authors: Delgado-Acevedo Johanna , Zamorano Angeline , DeYoung Randy W. , Campbell Tyler A. , Hewitt David G. , Long David B.
Published: December 2010

Context Feral pigs represent a significant threat to agriculture and ecosystems and are disease reservoirs for pathogens affecting humans, livestock and other wildlife. Information on the behavioural ecology of feral pigs might increase the efficiency and effectiveness of management strategies. Aims We assessed the frequency of promiscuous mating in relation to oestrous synchrony in feral pigs from southern Texas, USA, an agroecosystem with a widespread and well established population of feral pigs. An association between multiple paternity of single litters and synchrony of oestrous may indicate alternative mating strategies, such as mate-guarding. Methods We collected gravid sows at nine sites in southern Texas during 2005–07. We used a panel of DNA microsatellite markers to estimate frequency of multiple paternity and the distribution of male mating among litters of feral pigs. Conception dates were determined by fitting average fetal crown–rump measurements within litters to expected fetal development relative to gestation time. Key results We found evidence of multiple paternity in 21 of 64 litters (33%) from seven of nine sites sampled. Synchrony of oestrous did not influence promiscuous mating, as we found multiple paternity at sites with synchronous and asynchronous oestrous. Males sired from 8 to 11 offspring at three sites where >10 litters were sampled. Mean litter size (5.4) was less than the best-fit value for the number of offspring, indicating that some males sired offspring with ≥ 2 females. Key conclusions Feral pigs in Texas appear to be promiscuous under a range of demographic conditions, unlike wild boar and feral pigs in other regions. The ecological and behavioural factors affecting multiple paternity are not clear, but may include male–male competition, harassment avoidance, genetic benefits for offspring, response to macro-habitat conditions, or selection. Implications A high incidence of sexual contact among individuals may increase the opportunity for diseases transmitted by oral or venereal routes, such as swine brucellosis and pseudorabies. In addition, fertility-control methods targeting males only are likely to be inefficient if female promiscuity is high; methods targeting females or both sexes jointly may be more effective.
The use of scats as social signals in a solitary, endangered scincid lizard, Tiliqua adelaidensis
Authors: Fenner Aaron L. , Bull C. Michael
Published: December 2010

Context The deliberate accumulation of faeces or scats in one location is a common behaviour used for social signalling. The endangered pygmy bluetongue lizard, Tiliqua adelaidensis, is a solitary-living species that appears to use scats as social signals. Previous studies have found that these lizards approach burrows more cautiously if there is a conspecific scat present and behave differently to scats from male and female conspecifics, indicating that these lizards can recognise scat-based conspecific cues. For endangered species, understanding how an animal uses and responds to chemical cues has the potential to become a powerful tool in conservation management. Aims To investigate whether these solitary lizards might be using scats as social signals by testing whether scats were being deposited in a non-random pattern designed to maximise their exposure to the nearest neighbour conspecifics. Method In the present study, we investigated the spatial pattern of scatting behaviour by pygmy bluetongue lizards in the field. Results Scats were consistently deposited in one direction that was significantly aligned with the nearest occupied burrow of a neighbouring lizard. The same deposition sites were used when previous scats were either destroyed by rain, or experimentally moved to a different location. Male lizards deposited scats significantly closer to their own burrows when neighbours were closer. Key conclusions The results were consistent with the lizards using scats to advertise their presence and status. The scat-deposition patterns observed in the present study suggest that scats are used as an olfactory signal associated with social organisation of pygmy bluetongue lizards. Implications Current plans for the conservation management of this endangered species include translocations. By understanding how these lizards respond to, and use chemical cues, we may be able to use this knowledge to aid in translocation programs, e.g. by pre-establishing territories for individuals before they are introduced into the population.
Adopting and consuming innovations
Authors: Ozaki Ritsuko , Dodgson Mark
Published: December 2010

This paper aims to improve understanding of how innovations are diffused through combining perspectives on the adoption and consumption of innovation. The literature on the adoption of innovation mainly examines issues such as technical functionalities, utility and personality factors. In contrast, research on the consumption of innovation is concerned with the context and meaning of consumer decisions and the values that underlie them. The paper is conceptual and uses Weber’s categories of meaning in action to argue the value of combining the primarily ‘rational’ innovation adoption literature with the more ‘emotive’ consumption literature. By reference to the consumption of hybrid cars, we show how the innovation adoption literature can be valuably supplemented by an understanding of what consumers of innovation do, why they do it and what doing it means to them. We argue that this combination provides a more holistic understanding of how innovations diffuse and has implications for those delivering, using and researching innovation.
Unconventional competition – drawing lessons from the military
Authors: Ojiako Udechukwu , Johnson Johnnie , Chipulu Maxwell , Marshall Alasdair
Published: December 2010

We explore aspects of unconventional competition between firms. In particular, we address two critical questions. The first is: what happens when firms decide to compete outside the rules and frameworks of conventional competition? In other words, how should firms react to competitors who employ unconventional means of competition that differ from recognised Western ethical and legal norms? Secondly, we examine whether current warfare models provide guidance to firms facing such unconventional competition. To address these two questions, we seek to draw lessons from decision‐making approaches adopted by the military. We come to the conclusion that businesses can learn a great deal from how the military deals with unconventional competition.
Real and Imagined Body Movement Primes Metaphor Comprehension
Authors: Wilson Nicole L. , Gibbs Raymond W.
Published: December 2010

We demonstrate in two experiments that real and imagined body movements appropriate to metaphorical phrases facilitate people's immediate comprehension of these phrases. Participants first learned to make different body movements given specific cues. In two reading time studies, people were faster to understand a metaphorical phrase, such as push the argument, when they had previously just made an appropriate body action (e.g., a push movement) (Experiment 1), or imagined making a specific body movement (Experiment 2), than when they first made a mismatching body action (e.g., a chewing movement) or no movement. These findings support the idea that appropriate body action, or even imagined action, enhances people's embodied, metaphorical construal of abstract concepts that are referred to in metaphorical phrases.
Extreme enhancement of blocking temperature by strong magnetic dipoles interaction of α-Fe nanoparticle-based high-density agglomerate
Authors: Kura H , Takahashi M , Ogawa T
Published: December 2010

High-volume fraction α-Fe nanoparticle (NP) agglomerates were prepared using chemically synthesized NPs. In the agglomerate, NPs are separated by surfactant and NP superlattice with a hexagonal close-packed structure is locally realized. Volume fractions of NPs at 20% and 42% were obtained in agglomerates consisting of 2.9 nm and 8.2 nm diameter NPs, respectively. The high saturation magnetization of α-Fe NPs and high volume fraction of NPs in the agglomerate provide strong magnetic dipole–dipole interaction. The interaction energy of the agglomerate became much larger than the anisotropic energy of individual NPs. As a result, the blocking temperature of the 8.2 nm NP agglomerate was significantly enhanced from 52.2 K to around 500 K.
Large low-field magnetoresistance in Fe3O4/molecule nanoparticles at room temperature
Authors: Yue F J , Wang S , Lin L , Zhang F M , Li C H , Zuo J L , Du Y W , Wu D
Published: December 2010

Acetic acid molecule-coated Fe3O4 nanoparticles, 450–650 nm in size, have been synthesized using a chemical solvothermal reduction method. Fourier transform infrared spectroscopy measurements confirm one monolayer acetic acid molecules chemically bond to the Fe3O4 nanoparticles. The low-field magnetoresistance (LFMR) of more than −10% at room temperature and −23% at 140 K is achieved with saturation field of less than 2 kOe. In comparison, the resistivity of cold-pressed bare Fe3O4 nanoparticles is six orders of magnitudes smaller than that of Fe3O4/molecule nanoparticles, and the LFMR ratio is one order of magnitude smaller. Our results indicate that the large LFMR in Fe3O4/molecule nanoparticles is associated with spin-polarized electrons tunnelling through molecules instead of direct nanoparticle contacts. These results suggest that magnetic oxide-molecule hybrid materials are an alternative type of materials to develop spin-based devices by a simple low-cost approach.
Physical properties of Cu/La0.67Ba0.33MnO3/SrTiO3 : Nb junctions with ultrathin manganite layers
Authors: Gao Weiwei , Sun Xuan , Shen Baogen , Sun Jirong
Published: December 2010

We performed a systematic study on a Cu/La0.67Ba0.33MnO3/SrTiO3 : Nb (Cu/LBMO/STON) junction with a manganite layer, a few unit cells in width, focusing on the evolution of Cu–STON coupling as the film thickness of LBMO grew. The physical properties of the junction are found to be jointly determined by the electrode, the film and the substrate when the film thickness of LBMO is below ∼1 nm, with a carrier tunnelling process and a weakly rectifying feature. A LBMO film above ∼1 nm completely screens the electrode–substrate interaction, enhancing the rectifying character of the junctions significantly. A further increase in film thickness leads only to a minor modification of the junctions.
Ion collision cross sections with transport and reaction coefficients in Ar, Cl2 and N2 and their mixtures for photonic crystal applications
Authors: Hennad A , Yousfi M
Published: December 2010

The ion swarm transport coefficients such as reduced mobility, diffusion coefficients and reaction rates of the following systems Ar+/Cl2, Ar+/N2,
and
have been determined from a Monte Carlo simulation using calculated elastic and experimentally estimated inelastic collision cross sections. The elastic momentum transfer cross sections have been determined from a semi-classical JWKB approximation based on a rigid core interaction potential model. The inelastic cross sections have been fitted using the measured reaction coefficients as for instance ion conversion reaction coefficients. Then, the cross section sets are fitted using either the measured reduced mobility when available in the literature or the zero-field mobility calculated from Satoh's relation. From the sets of elastic and inelastic collision cross sections thus obtained in Ar+/Cl2, Ar+/N2,
and
systems, the ion transport and reaction coefficients are then calculated in pure gases and also in binary and ternary mixtures involving Cl2, Ar and N2 over a wide range of reduced electric field. These ion data are very useful for modelling and simulation of non-equilibrium low pressure electrical discharges used more particularly for etching of the III–V compounds in the case of crystal photonic applications.
Electroluminescence of dislocation-rich Si layers grown using oxidized Si surfaces
Authors: Shklyaev A A , Dultsev F N , Mogilnikov K P , Latyshev A V , Ichikawa M
Published: December 2010

Dislocation-rich Si layers are grown on a nanostructured surface composed of dense arrays of Ge islands that are formed on oxidized Si substrates. The p–i–n+ diodes fabricated on the basis of the grown layers exhibit electroluminescence (EL) in the 1.4–1.6 µm wavelength region. The current dependence of EL intensity appears to be different for the band-to-band transitions in the crystalline Si substrate and for the radiative transitions via dislocation-related deep states in the grown Si layers. The dependences are considered using a scheme of the electronic structure of the dislocated silicon and the Shockley–Read–Hall statistics of recombination processes. Deviations of the experimental dependences from the prediction of the statistics are attributed to the temperature and current variations of the injection coefficient.
Multiphoton absorption-induced optical whispering-gallery modes in ZnO microcavities at room temperature
Authors: Dai J , Xu C X , Sun L X , Chen Z H , Guo J Y , Li Z H
Published: December 2010

Ultralong ZnO microrods with a perfect hexagonal cross section were synthesized on a large scale by the vapour phase transport method and were employed as a whispering-gallery mode (WGM) cavity to realize optical resonance and lasing. An individual ZnO microrod was selected to investigate the multiphoton absorption-induced optical behaviours based on the enhancement of the nonlinear optical interaction in the WGM cavity. Three-photon absorption-induced UV lasing, second-harmonic generation and defect-related visible emission simultaneously present distinct WGMs under the excitation of femtosecond laser pulses at 1200 nm. When the pump laser was changed to 1240 nm, four-photon absorption-induced WGM lasing was observed. The characteristics and generation process of the above resonant signals were investigated in detail.