bluuebunny/crossref_metadata_2025 huggingface dataset:
Advancing the neuroscience of social emotions with social immersion
Authors: Krach Sören , Müller-Pinzler Laura , Westermann Stefan , Paulus Frieder M.
Published: July 2013

Second-person neuroscience offers a framework for the study of social emotions, such as embarrassment and pride. However, we propose that an enduring mental representation of oneself in relation to others without a continuous direct social interaction is possible. We call this state “social immersion” and will explain its impact on the neuroscience of social emotions.
Mirror neurons are central for a second-person neuroscience: Insights from developmental studies
Authors: Simpson Elizabeth Ann , Ferrari Pier Francesco
Published: July 2013

Based on mirror neurons' properties, viewers are emotionally engaged when observing others – even when not actively interacting; therefore, characterizing non-participatory action-viewing as isolated may be misleading. Instead, we propose a continuum of socio-emotional engagement. We also highlight recent developmental work that uses a second-person perspective, investigating behavioral, physiological, and neural activity during caregiver–infant interactions.
Modulating the sensitivity to syntactic factors in production: Evidence from syntactic priming in agrammatism
Authors: ROSSI ELEONORA
Published: July 2013

This study investigates the extent to which the production of complex morphosyntactic structures can be modulated in agrammatic speakers by utilizing a syntactic priming paradigm. Italian clitic pronouns (varying in morphosyntactic complexity) were chosen as the focal linguistic structure under investigation to test hypotheses based on alternative theories. Three experiments were performed. Experiment 1 analyzed clitic production in spontaneous speech. Experiments 2 and 3 used syntactic priming to prime the production of direct- and indirect-object clitics in finite and in restructuring sentences. These structures critically require different clitic positions (finite sentences: before the finite verb; restructuring sentences: before or after the verbal complex). The pattern of results shows that agrammatic speakers are impaired in clitic production. However, they show that the deficit is quantitative rather than qualitative, suggesting residual sensitivity despite the poor performance. The findings demonstrate that agrammatic (and control) speakers show a positive effect of syntactic priming across clitic types, suggesting that agrammatism can be characterized in terms of a linguistic processing deficit owing to increased processing demands for complex linguistic structures. Specifically, it is suggested that morphosyntactic complexity modulates both the level of impairment and the effect of priming for these grammatical structures.
Popular Science as CulturalDispositif: On the German Way of Science Communication in the Twentieth Century
Authors: Schirrmacher Arne
Published: July 2013

Argument

German twentieth-century history is characterized by stark changes in the political system and the momentous consequences of World Wars I and II. However, instead of uncovering specific kinds or periods of “Kaiserreich science,” “Weimar science,” or “Nazi science” together with their public manifestations and in such a way observing a narrow link between popular science and political orders, this paper tries to exhibit some remarkable stability and continuity in popular science on a longer scale. Thanks to the rich German history of scientific leadership in many fields, broad initiatives for science popularization, and a population and economy open to scientific progress, the media offered particularly rich popular science content, which was diversified for various audiences and interests. Closer consideration of the format, genre, quality, and quantity of popular science, and of the uses and value audiences attributed to it, along with their respective evolution, reveals infrastructures underpinning science communication. Rather than dealing with specific discourses, the conditions of science communication are at the center of this article. Therefore I focus on the institutions, rules, laws, and economies related to popular science, as well as on the philosophical, moral, and national propositions related to it, and also on the interactions among this ensemble of rather heterogeneous elements. This approach allows a machinery of popular scientific knowledge to be identified, in Foucauldian terms adispositif, one which is of a particularly cultural nature.
Cubulating one-relator groups with torsion
Authors: LAUER JOSEPH , WISE DANIEL T.
Published: July 2013

Let 〈a1, . . .,am∣wn〉 be a presentation of a groupG, wheren≥ 2. We define a system of codimension-1 subspaces in the universal cover, and invoke Sageev's construction to produce an action ofGon a CAT(0) cube complex. We show that the action is proper and cocompact whenn≥ 4. A fundamental tool is a geometric generalization of Pride'sC(2n) small-cancellation result. We prove similar results for staggered groups with torsion.
Ethylene in seed formation and germination
Authors: Matilla Angel J.
Published: July 2013

Abstract In seed formation the role of ethylene has received little attention. The data available on zygotic embryogenesis suggest an association of the ethylene biosynthetic pathway and seed maturation. Over the course of dicot embryogenesis, ACC-oxidase mRNA can be expressed in the cotyledons and embryonic axis. However, as maturation proceeds, cotyledonary ACC-oxidase expression disappears. In some seeds that develop primary dormancy, ethylene synthesis can be among the prerequisites for breaking dormancy. Moreover, the persistence of dormancy may be related to the difficulty of the embryonic axis to produce the necessary ethylene levels or to low tissue sensitivity. The use of inhibitors of ethylene biosynthesis or its action has provided data implicating an ethylene requirement for seed dormancy or germination in some species. However, the role of ethylene in germination remains controversial. Some authors hold that gas production is a consequence of the germination process, while others contend that ethylene production is a requirement for germination. Furthermore, among seeds that require ethylene, some are extremely sensitive to the gas, while others require relatively high levels to trigger germination. Recent studies withXanthium pennsylvanicumseeds suggest that β-cyanoalanine-synthase is involved in ethylene-dependent germination. In addition, regulation of the partitioning ofS-adenosyl-L-methionine (AdoMet) between the ethylene vs polyamine biosynthetic pathways may be a way of controlling germination in some seeds. Such regulation may also apply to the reversal of seed thermoinhibition, which can occur when polyamine synthesis is inhibited, thereby strongly channelling AdoMet towards ethylene. The biological models and approaches that may shed additional light on the role of ethylene during seed germination are presented.
HAS INFLATION TARGETING CHANGED THE CONDUCT OF MONETARY POLICY?
Authors: Creel Jérôme , Hubert Paul
Published: July 2013

We aim at establishing whether the institutional adoption of inflation targeting has changed the conduct of monetary policy. To do so, we test the hypothesis of inflation targeting translating into a stronger response to inflation in a Taylor rule with three alternative econometric models: a structural break model, a time-varying parameter model with stochastic volatility, and a Markov-switching VAR model. We conclude that inflation targeting has not led to a stronger response to inflation in the reaction function of the monetary authority. This result suggests that inflation targeting being meant to anchor inflation expectations through enhanced credibility and accountability, it may enable a central bank to stabilize inflation without pursuing aggressive action toward inflation variations.
Programmed cell death in the marine cyanobacterium Trichodesmium mediates carbon and nitrogen export
Authors: Bar-Zeev Edo , Avishay Itamar , Bidle Kay D , Berman-Frank Ilana
Published: July 2013

The extent of carbon (C) and nitrogen (N) export to the deep ocean depends upon the efficacy of the biological pump that transports primary production to depth, thereby preventing its recycling in the upper photic zone. The dinitrogen-fixing (diazotrophic) Trichodesmium spp. contributes significantly to oceanic C and N cycling by forming extensive blooms in nutrient-poor tropical and subtropical regions. These massive blooms generally collapse several days after forming, but the cellular mechanism responsible, along with the magnitude of associated C and N export processes, are as yet unknown. Here, we used a custom-made, 2-m high water column to simulate a natural bloom and to specifically test and quantify whether the programmed cell death (PCD) of Trichodesmium mechanistically regulates increased vertical flux of C and N. Our findings demonstrate that extremely rapid development and abrupt, PCD-induced demise (within 2–3 days) of Trichodesmium blooms lead to greatly elevated excretions of transparent exopolymers and a massive downward pulse of particulate organic matter. Our results mechanistically link autocatalytic PCD and bloom collapse to quantitative C and N export fluxes, suggesting that PCD may have an impact on the biological pump efficiency in the oceans.
Predator-induced changes in the growth of eyes and false eyespots
Authors: Lönnstedt Oona M. , McCormick Mark I. , Chivers Douglas P.
Published: July 2013

The animal world is full of brilliant colours and striking patterns that serve to hide individuals or attract the attention of others. False eyespots are pervasive across a variety of animal taxa and are among nature's most conspicuous markings. Understanding the adaptive significance of eyespots has long fascinated evolutionary ecologists. Here we show for the first time that the size of eyespots is plastic and increases upon exposure to predators. Associated with the growth of eyespots there is a corresponding reduction in growth of eyes in juvenile Ambon damselfish, Pomacentrus amboinensis. These morphological changes likely direct attacks away from the head region. Exposure to predators also induced changes in prey behaviour and morphology. Such changes could prevent or deter attacks and increase burst speed, aiding in escape. Damselfish exposed to predators had drastically higher survival suffering only 10% mortality while controls suffered 60% mortality 72 h after release.
Airway hyper-responsiveness in lipopolysaccharide-challenged common marmosets (Callithrix jacchus)
Authors: Curths Christoph , Wichmann Judy , Dunker Sarah , Windt Horst , Hoymann Heinz-Gerd , Lauenstein Hans D. , Hohlfeld Jens , Becker Tamara , Kaup Franz-Josef , Braun Armin , Knauf Sascha
Published: July 2013

Animal models with a high predictive value for human trials are needed to develop novel human-specific therapeutics for respiratory diseases. The aim of the present study was to examine lung-function parameters in marmoset monkeys (Callithrix jacchus) that can be used to detect pharmacologically or provocation-induced AHR (airway hyper-responsiveness). Therefore a custom-made lung-function device that allows application of defined aerosol doses during measurement was developed. It was hypothesized that LPS (lipopolysaccharide)-challenged marmosets show AHR compared with non-challenged healthy subjects. Invasive plethysmography was performed in 12 anaesthetized orotracheally intubated and spontaneously breathing marmosets. Pulmonary data of RL (lung resistance), Cdyn (dynamic compliance), EF50 (mid-expiratory flow), Poes (oesophageal pressure), MV (minute volume), respiratory frequency (f) and VT (tidal volume) were collected. Measurements were conducted under baseline conditions and under MCh (methacholine)-induced bronchoconstriction. The measurement was repeated with the same group of animals after induction of an acute lung inflammation by intratracheal application of LPS. PDs (provocative doses) of MCh to achieve a certain increase in RL were significantly lower after LPS administration. AHR was demonstrated in the LPS treated compared with the naïve animals. The recorded lung-function data provide ground for pre-clinical efficacy and safety testing of anti-inflammatory substances in the common marmoset, a new translational NHP (non-human primate) model for LPS-induced lung inflammation.
Molecular dynamics study of the pressure-dependent terahertz infrared absorption spectrum of α- and γ-RDX
Authors: Pereverzev Andrey , Sewell Thomas D. , Thompson Donald L.
Published: July 2013

Terahertz infrared absorption spectra of the α and γ polymorphs of 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) were predicted using two different theoretical approaches based on molecular dynamics simulations. The thermodynamic conditions studied were T = 298 K and hydrostatic pressures P = 0.0, 1.0, and 2.0 GPa for α-RDX and P = 3.0, 5.2, and 7.0 GPa for γ-RDX. The spectra obtained using the two methods are similar but not identical. In the case of α-RDX for pressure P = 0.0 GPa both spectra agree reasonably well with experimental data. The predicted spectra for α-RDX exhibit red-shifting (mode softening) of the main absorption peak with increasing pressure while for γ-RDX the spectra exhibit overall blue-shifting with increasing pressure.
Diffusion, adsorption, and desorption of molecular hydrogen on graphene and in graphite
Authors: Petucci Justin , LeBlond Carl , Karimi Majid , Vidali Gianfranco
Published: July 2013

The diffusion of molecular hydrogen (H2) on a layer of graphene and in the interlayer space between the layers of graphite is studied using molecular dynamics computer simulations. The interatomic interactions were modeled by an Adaptive Intermolecular Reactive Empirical Bond Order (AIREBO) potential. Molecular statics calculations of H2 on graphene indicate binding energies ranging from 41 meV to 54 meV and migration barriers ranging from 3 meV to 12 meV. The potential energy surface of an H2 molecule on graphene, with the full relaxations of molecular hydrogen and carbon atoms is calculated. Barriers for the formation of H2 through the Langmuir-Hinshelwood mechanism are calculated. Molecular dynamics calculations of mean square displacements and average surface lifetimes of H2 on graphene at various temperatures indicate a diffusion barrier of 9.8 meV and a desorption barrier of 28.7 meV. Similar calculations for the diffusion of H2 in the interlayer space between the graphite sheets indicate high and low temperature regimes for the diffusion with barriers of 51.2 meV and 11.5 meV. Our results are compared with those of first principles.
Effect of quantum tunneling on single strand breaks in a modeled gas phase cytidine nucleotide induced by low energy electron: A theoretical approach
Authors: Bhaskaran Renjith , Sarma Manabendra
Published: July 2013

Effect of quantum mechanical tunneling on single strand breaks induced by low energy electron (LEE) has been investigated in a modeled gas phase system, 2′-deoxycytidine-3′-monophosphate (3′-dCMPH). The potential energy curves for the sugar-phosphate C–O (3′ C–O) bond cleavage have been generated using second order Møller–Plesset perturbation theory at the 6-31+G(d) accuracy level. Results from the electronic structure theory calculations in conjunction with our time dependent calculations for the 3′ C–O bond rupture in 3′-dCMPH using local complex potential based time dependent wave packet approach show significant quantum tunneling of the 3′ C–O bond from the bound vibrational states above 1 eV of the anionic potential energy curve. A comparison of the fragmentation profile with that of our earlier gas phase investigations based on Hartree–Fock and density functional theory – Becke, 3-parameter, Lee-Yang-Parr methods with 6-31+G(d) basis set is also provided. Further, inspection of the singly occupied molecular orbitals generated at different 3′ C–O bond lengths clearly indicates the electron transfer from the low lying base–π* shape resonance state to the phosphate P = O π* orbital of the DNA backbone during the strand breaks. The decisive step during LEE induced strand breaks follows via “charge induced dissociation” (CID) for the metastable anion formed below 1 eV, whereas quantum mechanical tunnel-ing is out-weighted the CID mechanism for the LEE above 1 eV.
Disconjugacy, regularity of multi-indexed rationally extended potentials, and Laguerre exceptional polynomials
Authors: Grandati Y. , Quesne C.
Published: July 2013

The power of the disconjugacy properties of second-order differential equations of Schrödinger type to check the regularity of rationally extended quantum potentials connected with exceptional orthogonal polynomials is illustrated by re-examining the extensions of the isotonic oscillator (or radial oscillator) potential derived in kth-order supersymmetric quantum mechanics or multistep Darboux-Bäcklund transformation method. The function arising in the potential denominator is proved to be a polynomial with a nonvanishing constant term, whose value is calculated by induction over k. The sign of this term being the same as that of the already known highest degree term, the potential denominator has the same sign at both extremities of the definition interval, a property that is shared by the seed eigenfunction used in the potential construction. By virtue of disconjugacy, such a property implies the nodeless character of both the eigenfunction and the resulting potential.
Photoelectron spectroscopy of boron-gold alloy clusters and boron boronyl clusters: B3Aun− and B3(BO)n− (n = 1, 2)
Authors: Chen Qiang , Bai Hui , Zhai Hua-Jin , Li Si-Dian , Wang Lai-Sheng
Published: July 2013

Photoelectron spectroscopy and density-functional theory are combined to study the structures and chemical bonding in boron-gold alloy clusters and boron boronyl clusters: B3Aun− and B3(BO)n− (n = 1, 2). Vibrationally resolved photoelectron spectra are obtained for all four species and the B−Au and B−BO clusters exhibit similar spectral patterns, with the latter species having higher electron binding energies. The electron affinities of B3Au, B3Au2, B3(BO), and B3(BO)2 are determined to be 2.29 ± 0.02, 3.17 ± 0.03, 2.71 ± 0.02, and 4.44 ± 0.02 eV, respectively. The anion and neutral clusters turn out to be isostructural and isovalent to the B3Hn−/B3Hn (n = 1, 2) species, which are similar in bonding owing to the fact that Au, BO, and H are monovalent σ ligands. All B3Aun− and B3(BO)n− (n = 1, 2) clusters are aromatic with 2π electrons. The current results provide new examples for the Au/H and BO/H isolobal analogy and enrich the chemistry of boronyl and gold.
Hematin crystallization from aqueous and organic solvents
Authors: Ketchum Megan A. , Olafson Katy N. , Petrova Elena V. , Rimer Jeffrey D. , Vekilov Peter G.
Published: July 2013

Hematin crystallization is the main mechanism of detoxification of heme that is released in malaria-infected erythrocytes as a byproduct of the hemoglobin catabolism by the parasite. A controversy exists over whether hematin crystals grow from the aqueous medium of the parasite's digestive vacuole or in the lipid bodies present in the vacuole. To this end, we compare the basic thermodynamic and structural features of hematin crystallization in an aqueous buffer at pH 4.8, as in the digestive vacuole, and in water-saturated octanol that mimics the environment of the lipid nanospheres. We show that in aqueous solutions, hematin aggregation into mesoscopic disordered clusters is insignificant. We determine the solubility of the β-hematin crystals in the pH range 4.8–7.6. We image by atomic force microscopy crystals grown at pH 4.8 and show that their macroscopic and mesoscopic morphology features are incompatible with those reported for biological hemozoin. In contrast, crystals grown in the presence of octanol are very similar to those extracted from parasites. We determine the hematin solubility in water-saturated octanol at three temperatures. These solubilities are four orders of magnitude higher than that at pH 4.8, providing for faster crystallization from organic than from aqueous solvents. These observations further suggest that the lipid bodies play a role in mediating biological hemozoin crystal growth to ensure faster heme detoxification.
Modeling the collective relaxation time of glass-forming polymers at intermediate length scales: Application to polyisobutylene
Authors: Colmenero Juan , Alvarez Fernando , Khairy Yasmin , Arbe Arantxa
Published: July 2013

In a recent paper [V. N. Novikov, K. S. Schweizer, and A. P. Sokolov, J. Chem. Phys. 138, 164508 (2013)]10.1063/1.4802771 a simple analytical ansatz has been proposed to describe the momentum transfer (Q) dependence of the collective relaxation time of glass-forming systems in a wide Q-range covering the region of the first maximum of the static structure factor S(Q) and the so-called intermediate length scale regime. In this work we have generalized this model in order to deal with glass-forming systems where the atomic diffusive processes are sub-linear in nature. This is for instance the case of glass-forming polymers. The generalized expression considers a sub-linear jump-diffusion model and reduces to the expression previously proposed for normal diffusion. The generalized ansatz has been applied to the experimental results of the Q- and temperature-dependence of polyisobutylene (PIB), which were previously published. To reduce the number of free parameters of the model to only one, we have taken advantage of atomistic molecular dynamics simulations of PIB properly validated by neutron scattering results. The model perfectly describes the experimental results capturing both, Q- and temperature-dependences. Moreover, the model also reproduces the experimental Q-dependence of the effective activation energy of the collective relaxation time in the temperature range of observation. This non-trivial result gives additional support to the way the crossover between two different relaxation mechanisms of density fluctuations is formulated in the model.
Statistics of one-dimensional compressible turbulence with random large-scale force
Authors: Ni Qionglin , Shi Yipeng , Chen Shiyi
Published: July 2013

A numerical study was performed to explore the difference between the one-dimensional compressible hydrodynamic turbulence and Burgers turbulence. The compressible flows were simulated at three different turbulent Mach numbers (Mt): 0.1, 1.0, and 3.2, using a randomly large-scale forcing scheme. We observed that the isentropic condition was approximately valid in the Mt = 1.0 case, and its statistical scalings were close to that in the Burgers turbulence. We then used the subensemble method to decompose the velocity field of the Mt = 1.0 flow into two subensembles, according to the local energy fluxes in the positive and negative directions, respectively, and found that the subensemble probabilities were scale invariant in the inertial range. Further investigation on the interconversion between the two subensembles revealed that the transition in the compressible turbulence, unlike its Markovian counterpart in the Burgers turbulence, was not in accordance with a Markov process, and a mechanism for explaining this finding was then proposed.
Real-time X-ray scattering studies on temperature dependence of perfluoropentacene thin film growth
Authors: Frank C. , Novák J. , Gerlach A. , Ligorio G. , Broch K. , Hinderhofer A. , Aufderheide A. , Banerjee R. , Nervo R. , Schreiber F.
Published: July 2013

We report on real-time scattering investigations of growth of thin films of Perfluoropentacene (PFP) and its dependence on the substrate temperature, ranging between −120°C and 60°C. All films were grown up to 50 nm on silicon oxide. We find that along with the known thin-film phase, there is also a coexisting molecular arrangement with a unit cell twice the size with respect to the long axis. Furthermore, we observe that even at temperatures as low as −20°C PFP shows a high degree of crystallinity in the out-of-plane direction. The growth of PFP is characterized by a two-stage process, where the molecular lattice experiences a much stronger in-plane relaxation in the thickness regime 0–19 nm compared to the thickness regime 19–50 nm, which can be probed only by in situ real-time scattering measurements.
The effect of thermal treatment induced inter-diffusion at the interfaces on the charge trapping performance of HfO2/Al2O3 nanolaminate-based memory devices
Authors: Lan Xuexin , Ou Xin , Cao Yanqiang , Tang Shiyu , Gong Changjie , Xu Bo , Xia Yidong , Yin Jiang , Li Aidong , Yan Feng , Liu Zhiguo
Published: July 2013

The charge trapping memory devices based on different HfO2/Al2O3 nanolaminated charge trapping layers were prepared and investigated. The memory device with 6 interfaces HfO2/Al2O3 shows a memory window of 4.7 V in its capacitance-voltage curve and a better retention property. It was suggested that the thermal treatment would reduce the defects inside the bulk HfO2, but cause an inter-diffusion at the interface HfO2/Al2O3, which could create additional defects at HfO2/Al2O3 interface. Increasing the number of the interfaces could enhance the charge trapping capability of the devices. The band alignments were established to explain the variation trend of the memory window and the retention characteristics of the memory devices with different laminated structures.
Selective laser melting of La(Fe,Co,Si)13 geometries for magnetic refrigeration
Authors: Moore J. D. , Klemm D. , Lindackers D. , Grasemann S. , Träger R. , Eckert J. , Löber L. , Scudino S. , Katter M. , Barcza A. , Skokov K. P. , Gutfleisch O.
Published: July 2013

Magnetic cooling prototypes based on the magnetocaloric effect require the magnetic refrigerant to be shaped into geometries that enable quick and efficient heat-transfer to the transfer fluid. Simple solutions include a stack of parallel-plates or a bed of packed-spheres. Here, we demonstrate how more sophisticated geometries can be made by using selective laser melting, a rapid prototyping technique to form three-dimensional shapes. Using excellent magnetocaloric La(Fe,Co,Si)13 as starting-powder we made two geometries: a wavy-channel block with a high surface-to-volume ratio and an array of fin-shaped rods which eliminate unwanted heat conduction along the magnetic part. After annealing treatment, the geometries are intact and can survive more than 106 cycles of applying a magnetic field while still maintaining good magnetocaloric properties. This fabrication approach shows promise for making near-net shaped magnetic refrigerants with superior heat transfer properties and performance.
The effect of electron induced hydrogenation of graphene on its electrical transport properties
Authors: Woo Sung Oh , Teizer Winfried
Published: July 2013

We report a deterioration of the electrical transport properties of a graphene field effect transistor due to energetic electron irradiation on a stack of Poly Methyl Methacrylate (PMMA) on graphene (PMMA/graphene bilayer). Prior to electron irradiation, we observed that the PMMA layer on graphene does not deteriorate the carrier transport of graphene but improves its electrical properties instead. As a result of the electron irradiation on the PMMA/graphene bilayer, the Raman “D” band appears after removal of PMMA. We argue that the degradation of the transport behavior originates from the binding of hydrogen generated during the PMMA backbone secession process.
Manifestations in the magnetization of the hcp-Co nanowires due to interdependence of aspect ratio and c-axis orientation
Authors: Kaur Daljit , Chaudhary Sujeet , Pandya D. K.
Published: July 2013

Effect of interdependence of aspect ratio (AR) and c-axis orientation of the hcp-cobalt nanowires (NWs) on their magnetization behavior is reported in 40 and 100 nm diameter NWs. Experimental evidence of periodically modulated magnetic state viz. large transverse-susceptibility arising due to orientation of c-axis normal to NW-axis in 40 nm NWs and magnetic domain imaging is demonstrated, which disappears at low AR owing to randomly oriented c-axes. The 100 nm NWs exhibit a crossover in the easy-axis direction from longitudinal at high AR to transverse at low AR and are explained on the basis of competition between different anisotropic contributions.
Identification of geometrically necessary dislocations in solid phase crystallized poly-Si
Authors: Law Felix , Yi Yang , Hidayat  , Widenborg Per I. , Luther Joachim , Hoex Bram
Published: July 2013

In this work, the presence of geometrically necessary dislocations (GNDs) in polycrystalline silicon (poly-Si) thin films was detected, suggesting that plastic deformation occurs during the solid phase crystallization (SPC) process of amorphous silicon (a-Si:H). Electron backscatter diffraction was used to characterize dislocations in SPC poly-Si thin films. The elevated temperatures during SPC allow the GNDs to rearrange into arrays, forming low angle grain boundaries. We found that GNDs start forming in poly-Si grains with sizes >∼3 μm, suggesting that larger grains are more defective. GNDs are extra defects in addition to the existing statistically stored dislocations that form during grain growth and hence more care needs to be taken to minimize the formation of GNDs.
Ferritin protein encapsulated photoluminescent rare earth nanoparticle
Authors: Harada T. , Yoshimura H.
Published: July 2013

Rare earth (yttrium (Y), europium (Eu), and terbium (Tb)) nanoparticles and Eu and Tb doped Y nanoparticles are synthesized in an apoferritin cavity. They exhibit a narrow size distribution and a high stability in an aqueous solution at pH 8.5. Eu and Eu doped Y (Y:Eu) nanoparticles exhibit red photoluminescence (emission peaks: 590 and 614 nm), while Tb and Tb doped Y (Y:Tb) nanoparticles exhibit green photoluminescence (emission peaks: 488, 544, 582, and 618 nm). High-resolution electron microscopy observations reveal that about 5% of the nanoparticles have a lattice structure, while the remaining nanoparticles are amorphous. Electron diffraction of the Y nanoparticles gives lattice spacings corresponding to the cubic structure of yttrium oxide (Y2O3). The most optimal dopant content for luminescence of Y:Eu and Y:Tb nanoparticles in apoferritin cavity are about 60% and 40%, respectively.
Distributed feedback quantum cascade laser with optically tunable emission frequency
Authors: Suchalkin S. , Belenky G. , Hosoda T. , Jung S. , Belkin M. A.
Published: July 2013

Continuous tuning of a room-temperature-operated distributed feedback quantum cascade laser in the range of 0.6 cm−1 (20 GHz) was achieved using 1.3 μm telecom diode laser as a pumping source. We demonstrate wavelength modulation of the quantum cascade laser at frequencies up to 300 MHz.
Zero-field cooled exchange bias in hexagonal YMnO3 nanoparticles
Authors: Chauhan Samta , Kumar Srivastava Saurabh , Chandra Ramesh
Published: July 2013

Effect of varying particle size and maximum applied field during initial magnetization (HM) on zero-field cooled (ZFC) exchange bias (EB) in hexagonal YMnO3 nanoparticles prepared by conventional solid state method has been studied. EB phenomenon is observed after ZFC from an unmagnetized state without any remanent magnetization. EB field (Heb) and Vertical shift (ME) were found to vary nonmonotonically with both particle size and HM. Large Heb of 1024 Oe is obtained for the particle size of 55 nm. These features are attributed to the exchange interaction between the compensated antiferromagnetic spins and uncompensated surface spins of the nanoparticles.
Conductance quantization in oxygen-anion-migration-based resistive switching memory devices
Authors: Chen C. , Gao S. , Zeng F. , Wang G. Y. , Li S. Z. , Song C. , Pan F.
Published: July 2013

Quantized conductance was observed in an anion-migration-based resistive switching memory cell with the structure of (Ti, Ta, W)/Ta2O5/Pt. The conductance of the cell varies stepwise in units of single atomic conductance (77.5 μS), which is responsible for the formation and annihilation of atomic scale filament built from oxygen vacancies in Ta2O5 film. The quantized conductance behavior can be modulated by voltage pulses as fast as 100 ns. The demonstration of conductance quantization in Ta2O5 based memory device would open the door for quantized multi-bit data storage of anion-migration-based resistive switching nonvolatile memories.
Non-destructive and rapid evaluation of chemical vapor deposition graphene by dark field optical microscopy
Authors: Kong X. H. , Ji H. X. , Piner R. D. , Li H. F. , Magnuson C. W. , Tan C. , Ismach A. , Chou H. , Ruoff R. S.
Published: July 2013

Non-destructive and rapid evaluation of graphene directly on the growth substrate (Cu foils) by dark field (DF) optical microscopy is demonstrated. Without any additional treatment, graphene on Cu foils with various coverages can be quickly identified by DF imaging immediately after chemical vapor deposition growth with contrast comparable to scanning electron microscopy. The improved contrast of DF imaging compared to bright field optical imaging was found to be due to Rayleigh scattering of light by the copper steps beneath graphene. Indeed, graphene adlayers are readily distinguished, due to the different height of copper steps beneath graphene regions of different thickness.
How to detect a genuine quantum pump effect in graphene?
Authors: Benjamin Colin
Published: July 2013

Quantum pumping in graphene has been predicted in recent years. Till date there have been no experiments indicating a graphene based quantum pump. This is not uncommon as in the case of other non-Dirac behavior showing materials it has not yet been unambiguously experimentally detected. The reason is that in experiments with such materials the rectification effect overshadows the pumped current. In this work we answer the question posed in the title by taking recourse to “strain.” We show that the symmetries of the rectified and pumped currents towards strain reversal can effectively distinguish between the two.
Mid-infrared optical near-field switching in heterogeneous graphene ribbon pairs
Authors: Wang Lei , Cai Wei , Zhang Xinzheng , Liu Penghong , Xiang Yinxiao , Xu Jingjun
Published: July 2013

The spatial switching of mid-infrared light near-fields is proposed in coupled graphene heterogeneous ribbon pairs. By using the coupled plasmon modes in graphene ribbon pairs, the electric near-field enhancement can be spatially controlled in graphene ribbons as the tuning of the external bias voltage difference. More specifically, due to symmetry breaking, the anti-symmetrically coupled dipolar plasmons exist except for the symmetrically coupled modes in homogeneous graphene pairs. Moreover, the gap distance is one of the key parameters for switching of electric near-fields, strong coupling means the efficient control of near-fields.
Single-crystalline CuO nanowire growth and its electrode-dependent resistive switching characteristics
Authors: Kim Deok-kee , Ho Shin Jeong , Sun Shin Ho , Yong Song Jae
Published: July 2013

Resistive switching characteristics of single-crystalline CuO nanowires grown by thermal oxidation was investigated. The compressive stress developed in Cu2O layer prevented further oxidation of Cu and caused CuO nanowire growth, which was driven by the total Gibbs free energy minimization. CuO nanowire with Pt electrode showed Ohmic below 1.1 V and space charge limited current above 1.1 V, while that with Cu electrode showed resistive switching characteristics with sufficient Cu ions to form the metallic filaments from the electrodes.
Effect of thermal annealing on Boron diffusion, micro-structural, electrical and magnetic properties of laser ablated CoFeB thin films
Authors: Swamy G. Venkat , Pandey Himanshu , Srivastava A. K. , Dalai M. K. , Maurya K. K. , Rashmi  , Rakshit R. K.
Published: July 2013

We report on Boron diffusion and subsequent crystallization of Co40Fe40B20 (CoFeB) thin films on SiO2/Si(001) substrate using pulsed laser deposition. Secondary ion mass spectroscopy reveals Boron diffusion at the interface in both amorphous and crystalline phase of CoFeB. High-resolution transmission electron microscopy reveals a small fraction of nano-crystallites embedded in the amorphous matrix of CoFeB. However, annealing at 400°C results in crystallization of CoFe with bcc structure along (110) orientation. As-deposited films are non-metallic in nature with the coercivity (Hc) of 5Oe while the films annealed at 400°C are metallic with a Hc of 135Oe.
Transport properties of ZnTe:N thin films
Authors: Chi Hang , Chen Chihyu , Phillips Jamie D. , Uher Ctirad
Published: July 2013

Highly mismatched alloys have been predicted to exhibit enhanced thermoelectric properties. Here we report on transport properties of one such system, nitrogen-doped ZnTe epitaxial layers on GaAs (100). Hall effect, electrical resistivity, and Seebeck coefficient measurements were performed between 5 K and 300 K for samples with a room temperature hole concentration of 0.34–2.16 × 1019 cm−3. Significant phonon-drag thermopower reaching 1.5–2.5 mV K−1 was observed. Fermi-Dirac statistics was used to analyze the transport parameters of ZnTe:N films assuming a single parabolic band. The power factor demonstrates a measurable improvement with increasing nitrogen concentration.
Note: Amplification characteristics of all-normal-dispersion mode-locked Yb-doped fiber laser: Influence of input pulse shape
Authors: Mukhopadhyay Pranab K. , Gupta Pradeep K. , Bindra Kushvinder S. , Oak Shrikant M.
Published: July 2013

The amplification properties of the pulses at and after the nonlinear polarization rejection (NPR) port of an all-normal-dispersion Yb-doped mode-locked fiber laser are studied. The experimental results show that the spectra of the output pulses after the NPR port are considerably resistant to distortions on amplification and can be compressed in the femtosecond regime without any significant side-lobes and hence can serve as an excellent seed source for further power amplification. The experimental results are substantiated by numerical analysis of the amplifier setup.
Oligothiophene-based monolayer field-effect transistors prepared by Langmuir-Blodgett technique
Authors: Sizov Alexey S. , Agina Elena V. , Gholamrezaie Fatemeh , Bruevich Vladimir V. , Borshchev Oleg V. , Paraschuk Dmitry Yu. , de Leeuw Dago M. , Ponomarenko Sergey A.
Published: July 2013

Quinquethiophene-based monolayer organic field-effect transistors (OFETs) prepared by Langmuir-Blodgett (LB) technique show hole mobilities up to 10−2 cm2/Vs and On/Off ratios up to 106. Functional logic LB monolayer devices operating in air have been demonstrated. The performance of LB OFETs is comparable to self-assembled monolayer field-effect transistors (SAMFETs) devices prepared by self-assembly from solution using the same organosilicon oligothiophene despite the LB OFET monolayer is weakly bounded to the dielectric surface. Taking into account that the LB technique is a fast and rather easy process, these findings highlight a high potential of LB technique for ultrathin organic electronics.
Anisotropy of radiation emitted from planar wire arrays
Authors: Kantsyrev V. L. , Chuvatin A. S. , Esaulov A. A. , Safronova A. S. , Rudakov L. I. , Velikovich A. , Williamson K. M. , Osborne G. C. , Shrestha I. K. , Weller M. E. , Shlyaptseva V. V.
Published: July 2013

The planar wire array (PWA) is a promising load for new multi-source inertial confinement fusion (ICF) hohlraums [B. Jones et al., Phys. Rev. Lett. 104, 125001 (2010)]. The hohlraum radiation symmetry is an important issue for ICF. It was found that extreme ultraviolet and sub-keV photon emission from PWAs may have considerable anisotropy in the load azimuthal plane. This experimental result is obtained on the UNR 1–1.7 MA Zebra generator. The time-dependent anisotropy effect is detected. This feature is studied in 2D numerical simulations and can be explained by initial anisotropy of implosion of those non-cylindrical loads radiating essentially as surface sources in sub-keV quanta and also by radiation absorption in cold magnetized plasma tails forming in the direction of magnetic compression.
Reliability and validity of the International Physical Activity Questionnaire–Short Form for older adults in Vietnam
Authors: Tran Dinh V. , Lee Andy H. , Au Thuy B. , Nguyen Chung T. , Hoang Dong V.
Published: July 2013

Issues addressed

The International Physical Activity Questionnaire (IPAQ) was developed as a global standard questionnaire to monitor physical activity across diverse populations. In Vietnam, the IPAQ‐Short Form (SF) has only been tested for reliability and validity among adolescents. The present study determined test‐retest reliability and criterion validity of the IPAQ‐SF for older Vietnamese adults aged 60–75 years.

Methods

In all, 197 participants were recruited from the community. Subjects were requested to wear a pedometer, record daily steps and list all physical activities in a log‐book for 7 consecutive days. Those who completed the requirements were interviewed using the IPAQ‐SF (IPAQ1). A repeated interview was arranged 3 days later (IPAQ2).

Results

The final sample consisted of 150 participants (75 men, 75 women) with mean (± s.d.) age of 66.8 ± 5.1 years. The intraclass correlation coefficients between IPAQ1 and IPAQ2 exceeded 0.80 for all physical activity domains and sitting, indicating good reliability. However, fair to weak validity was evident between IPAQ1 measures and activity log and pedometer readings, with Spearman correlations of 0.46 and 0.20, respectively.

Conclusions

The Vietnamese translated version of IPAQ‐SF appears to be a reliable and reasonably valid instrument to assess and monitor habitual physical activity for older adults in Vietnam.

So what?

The IPAQ‐SF could provide useful physical activity data to evaluate the effectiveness of health promotion intervention programs and for international comparison purposes.
Word learning is mediated by the left arcuate fasciculus
Authors: López-Barroso Diana , Catani Marco , Ripollés Pablo , Dell'Acqua Flavio , Rodríguez-Fornells Antoni , de Diego-Balaguer Ruth
Published: July 2013

Human language requires constant learning of new words, leading to the acquisition of an average vocabulary of more than 30,000 words in adult life. The ability to learn new words is highly variable and may rely on the integration between auditory and motor information. Here, we combined diffusion imaging tractography and functional MRI to study whether the strength of anatomical and functional connectivity between auditory and motor language networks is associated with word learning ability. Our results showed that performance in word learning correlates with microstructural properties and strength of functional connectivity of the direct connections between Broca’s and Wernicke’s territories in the left hemisphere. This study suggests that our ability to learn new words relies on an efficient and fast communication between temporal and frontal areas. The absence of these connections in other animals may explain the unique ability of learning words in humans.
Clades reach highest morphological disparity early in their evolution
Authors: Hughes Martin , Gerber Sylvain , Wills Matthew Albion
Published: July 2013

There are few putative macroevolutionary trends or rules that withstand scrutiny. Here, we test and verify the purported tendency for animal clades to reach their maximum morphological variety relatively early in their evolutionary histories (early high disparity). We present a meta-analysis of 98 metazoan clades radiating throughout the Phanerozoic. The disparity profiles of groups through time are summarized in terms of their center of gravity (CG), with values above and below 0.50 indicating top- and bottom-heaviness, respectively. Clades that terminate at one of the “big five” mass extinction events tend to have truncated trajectories, with a significantly top-heavy CG distribution overall. The remaining 63 clades show the opposite tendency, with a significantly bottom-heavy mean CG (relatively early high disparity). Resampling tests are used to identify groups with a CG significantly above or below 0.50; clades not terminating at a mass extinction are three times more likely to be significantly bottom-heavy than top-heavy. Overall, there is no clear temporal trend in disparity profile shapes from the Cambrian to the Recent, and early high disparity is the predominant pattern throughout the Phanerozoic. Our results do not allow us to distinguish between ecological and developmental explanations for this phenomenon. To the extent that ecology has a role, however, the paucity of bottom-heavy clades radiating in the immediate wake of mass extinctions suggests that early high disparity more probably results from the evolution of key apomorphies at the base of clades rather than from physical drivers or catastrophic ecospace clearing.
Consequences of Incidental Otter Trawl Capture on Survival and Physiological Condition of Threatened Atlantic Sturgeon
Authors: Beardsall Jeffrey W. , McLean Montana F. , Cooke Steven J. , Wilson Brian C. , Dadswell Michael J. , Redden Anna M. , Stokesbury Michael J. W.
Published: July 2013

Atlantic Sturgeon Acipenser oxyrinchus aggregate in Minas Basin in the inner Bay of Fundy, Nova Scotia, during summer, presumably to feed on abundant intertidal invertebrates. The Atlantic Sturgeon aggregation is composed of multiple stocks from Canada and the USA. Government agencies from both nations have recently recognized Atlantic Sturgeon as threatened or endangered due to overfishing and habitat degradation. Little is known about the fate of Atlantic Sturgeon that are captured as bycatch in fisheries targeting other species, making it difficult to determine the extent to which bycatch is contributing to the Atlantic Sturgeon population's decline. To characterize the effects of otter trawl capture and release on Atlantic Sturgeon, we calculated a minimum survival rate for fish after catch and release by using acoustic telemetry, and we examined physiological indicators of stress. The minimum postrelease survival rate from otter trawl capture events was high (94% survival). Results also demonstrated that the magnitude of blood lactate in trawl‐captured fish relative to experimental control fish increased with longer handling times. Trawl capture and handling did not cause significantly elevated levels of blood glucose or cortisol relative to those of controls. Minimization of handling time (i.e., time on deck) should be a priority in trawl fisheries that capture Atlantic Sturgeon as bycatch. Future studies should attempt to quantify the postcapture behavior of these fish to better understand whole‐organism condition after fisheries encounters.