bluuebunny/crossref_metadata_2025 huggingface dataset:
Eye gaze and conscious processing in severely brain-injured patients
Authors: Chatelle Camille , Laureys Steven , Majerus Steve , Schnakers Caroline
Published: January 2011

Niedenthal et al. discuss the importance of eye gaze in embodied simulation and, more globally, in the processing of emotional visual stimulation (such as facial expression). In this commentary, we illustrate the relationship between oriented eye movements, consciousness, and emotion by using the case of severely brain-injured patients recovering from coma (i.e., vegetative and minimally conscious patients).
Embodied simulation and the meaning of facial expression in autism
Authors: Evers Kris , Noens Ilse , Steyaert Jean , Wagemans Johan
Published: January 2011

We outline three possible shortcomings of the SIMS model and specify these by applying the model to autism. First, the SIMS model assigns a causal role to brain processes, thereby excluding individual and situational factors. Second, there is no room for subjective and high-level conceptual processes in the model. Third, disentangling the different stages in the model is very difficult.
Grounding the meaning of non-prototypical smiles on motor behavior
Authors: Mann Timothy A. , Choe Yoonsuck
Published: January 2011

We address how the motor system can contribute to the “meaning” component of smile perception. A smile perceiver can ground the meaning of non-prototypical smiles by interacting with the presenter to maintain the presenter's type of smile. In this case, the meaning of that smile is congruent with the motor behavior that elicits that smile (such as a funny gesture).
What's embodied in a smile?
Authors: Sauter Disa A. , Levinson Stephen C.
Published: January 2011

Differentiation of the forms and functions of different smiles is needed, but they should be based on the empirical data on distinctions that senders and receivers make and on the physical cues that are employed. Such data would allow for a test of whether smiles can be differentiated using perceptual cues alone or whether mimicry or simulation are necessary.
Expressive smiles or leucosignals?
Authors: Bouissac Paul
Published: January 2011

The assumption that a complex and fuzzy notion like smile can be the basis of a scientific, rather than semantic, inquiry can only lead to confused and inconclusive results. It would be more productive to start with the well-defined and measurable patterns of the clearly visible contrasts that are produced on the human face by various muscular contractions around the white patches formed by the sclera and the teeth. These features are universal, whereas a common word, in whatever language, is necessarily ambiguous, culture-dependent, and historically rather than biologically determined.
Embodied and disembodied processing of emotional expressions: Insights from autism spectrum disorders
Authors: Winkielman Piotr
Published: January 2011

Processing of facial expressions goes beyond simple pattern recognition. To elucidate this problem, Niedenthal et al. offer a model that identifies multiple embodied and disembodied routes for expression processing, and spell out conditions triggering use of different routes. I elaborate on this model by discussing recent research on emotional recognition in individuals with autism, who can use multiple routes of emotion processing, and consequently can show atypical and typical patterns of embodied simulation and mimicry.
The flawed logic of a MAD man: Craig's contribution to Power Preponderance theory
Authors: GLENN JOHN
Published: January 2011

In a recent issue of this journal Campbell Craig put forward an amended version of Power Preponderance theory seeking to explain why US unipolar predominance has turned out to be not simply a ‘moment’ and as such represents ‘a serious anomaly for neorealist theory’.In using Waltz's own work on how nuclear weapons affect state behaviour, Craig appears to further bolster the case for Power Preponderance theory. Craig exploits what at first sight seems to be a contradiction in Waltz's work. However, Craig's error is that he treats securityquaterritorial security rather than considering a more encompassing view of state security. In the arena of ‘secondary’ security issues the usual logic of counter-balancing with conventional military forces still holds sway. This reply argues that a balance of power will return to the international system, it is just that at this moment no country or coalition of countries is quite up to the task.
Targum and Translation: A New Approach to a Classic Problem
Authors: Lasair Simon G. D. A.
Published: January 2011

The targums to the Pentateuch have often been called a kind of translation literature. In part, this is due to the lexicography of the termtargum, according to which this literature is known. Although this association between targumic literature and the termtranslationhas been long-standing, “translation,” as it has been used in the field of targum studies, is greatly undertheorized. Within recent years, scholars have used the wordtranslationto describe the interlinguistic rendering of specific Hebrew Bible words and phrases. Some discussion has been given to the complexities of this dynamic in the targums, but the meaning of the termtranslationhas yet to be addressed explicitly. In this article, I propose that to usetranslationas a meaningful descriptive category for targumic literature, it is necessary to unpack it and examine its ambiguities and problematic status even within the context of discussions about translation studies. By exploring the contours of this term, I hope to indicate how a more nuanced understanding of “translation” can help describe the targumic genre, as well as the targums' underlying hermeneutic orientation toward the Hebrew Bible.
What Is a Jewish Book?
Authors: Dweck Yaacob
Published: January 2011

Moritz Steinschneider opened the greatest monument in the study of Hebrew bibliography, hisCatalogus Librorum Hebraeorum in Bibliotheca Bodleiana, with the following statement:

Our catalog, which we have designated “The Catalog of Hebrew Books in the Bodleian Library” because it is best, contains a concise and detailed overview of the majority of Hebrew books, as well as some that pertain in a way to Jewish literature.
Effect of weather variability on the incidence of mumps in children: a time-series analysis
Authors: ONOZUKA D. , HASHIZUME M.
Published: January 2011

The increasing international interest in the potential health effects of climate change has emphasized the importance of investigations into the relationship between weather variability and infectious diseases. However, few studies have examined the impact of weather variability on mumps in children, despite the fact that children are considered particularly vulnerable to climate change. We acquired data about cases of mumps in children aged <15 years and weather variability in Fukuoka, Japan from 2000 to 2008, and then used time-series analyses to assess how weather variability affected mumps cases, adjusting for seasonal variations, inter-annual variations, and temporal variations of two large epidemics in 2001 and 2004–2005. The weekly number of mumps cases increased by 7·5% (95% CI 4·0–11·1) for every 1°C increase in average temperature and by 1·4% (95% CI 0·5–2·4) for every 1% increase in relative humidity. The percentage increase was greatest in the 0–4 years age group and tended to decrease with increasing age. The number of mumps cases in children increased significantly with increased average temperature and relative humidity.
Serialism and locality in constraint-based metrical parsing
Authors: Pruitt Kathryn
Published: January 2011

This paper proposes a model of stress assignment in which metrical structure is built serially, one foot at a time, in a series of Optimality Theory (OT)-style evaluations. Iterative foot optimisation is made possible in the framework of Harmonic Serialism, which defines the path from an input to an output with a series of gradual changes in which each form improves harmony relative to a constraint ranking. Iterative foot optimisation makes the strong prediction that decisions about metrical structure are made locally, matching attested typology, while the standard theory of stress in parallel OT predicts in addition to local systems unattested stress systems with non-local interactions. The predictions of iterative foot optimisation and parallel OT are compared, focusing on the interactions of metrical parsing with syllable weight, vowel shortening and constraints on the edges of prosodic domains.
All's Well That Bends Well? The Constitutional Dimension to the Services Directive
Authors: van de Gronden Johan , de Waele Henri
Published: January 2011

Services Directive – Peculiar harmonisation technique – Unusual design – Key provisions giving rise to constitutional problems – Special derogation system – Freezing of the Rule of Reason – (In)compatibility with EU primary law – Appropriate legal basis? – Non–transposition by several member states – Arguments for a benign assessment of the Commission and the Court – Problematic enforcement in horizontal situations – Possible solutions and their shortcomings – Overall need for a flexible approach
The European Political Order and Internet Piracy: Accidental or Paradigmatic Constitution-Shaping?
Authors: Jančić Davor
Published: January 2011

Modern age technology spurs legal development – Temporal coincidence of conflicting national and Union legislative processes triggers interdependence between EU and member states – French Loi Hadopi cuts Internet without recourse to a court – Conseil constitutionnel enshrines Internet as fundamental freedom – EU telecoms reform incorporates several French fundamental rights safeguards
German Federal Constitutional Court: German Data Retention Provisions Unconstitutional in Their Present Form; Decision of 2 March 2010, NJW 2010, p. 833.
Authors: Kaiser Anna-Bettina
Published: January 2011

About one year after the European Court of Justice had handed down its notorious decision on the Data Retention Directive concerning telecommunications traffic data, it was for the German Federal Constitutional Court to take a final decision on the German implementation of the Directive. So far, the latter Court had only issued temporary injunctions restricting data retrieval by the public authorities. Now, the final ruling by the Court has been anxiously awaited since the complainants had not only challenged the German provisions implementing the Directive, but also the Directive itself. Thus, the question was raised whether the Court would finally, for the first time in its history, initiate a preliminary ruling procedure according to Article 267 of the Treaty on the Functioning of the European Union.
Sexual Politics and Ascriptive Autonomy
Authors: Ben-Ishai Elizabeth
Published: January 2011

I explore the notion of ascriptive autonomy as a conceptual and political tool that can be used to understand and enact potentially liberatory practices that enable marginalized people to have greater individual autonomy. “Ascriptive autonomy” refers to the sense in which autonomy is partly constituted by the conferral of the status of “autonomous individual.” Autonomy is both a capacity to determine one's own ends and a status conferred by virtue of being recognized by others. I focus on the link between these two facets of autonomy insofar as recognition may enable the development of capacity. In certain situations, autonomy may be ascribed even if one lacks some requirements associated with the capacity for autonomy because of either institutional or psychic constraints that follow from oppression. In such instances of “selective, purposeful misrecognition,” ascription may lead to the cultivatation of the capacity for autonomy while opening up a space for politics. To demonstrate this, I recast the feminist debate over sexuality using the terms of ascriptive autonomy. When viewed through the lens of misrecognition, we can better respond to critiques that charge proponents of the “pro-sex”position with focusing on sexual pleasure at the expense of sufficient attention paid to the constraints faced by women.
When No “Official Record” Exists?
Authors: Grey Sandra J.
Published: January 2011

Social movements seek social and political change in very specific political, economic, and cultural contexts. Their very imperative for structural change means that they are nonbureaucratic, noninstitutional, fluid collectives that have no single head office and few formal records of their existence. This poses a substantial problem for researchers—how do we locate, measure, and record the trajectories of these phenomena?
New extraction method of an equivalent circuit for an inductor in BiCMOS technology including lossy effects
Authors: Tran Linh Nguyen , Bourdel Emmanuelle , Quintanel Sebastien , Pasquet Daniel
Published: January 2011

In order to perform an accurate design, in particular in non-linear circuit, the equivalent circuit of inductors must be precisely described in a wide frequency band. Many models have been proposed to describe the behavior of inductors on lossy substrate. They consist of a great number of elements, often suggested by physical phenomena. Most of them cannot be extracted from measurements. In this paper, we propose a model composed only of elements that can be analytically extracted from measurement results.
Cenozoic deformation of Iberia: A model for intraplate mountain building and basin development based on analogue modeling
Authors: Fernández‐Lozano J. , Sokoutis D. , Willingshofer E. , Cloetingh S. , De Vicente G.
Published: January 2011

Inferences from analogue models support lithospheric folding as the primary response to large‐scale shortening manifested in the present day topography of Iberia. This process was active from the late Oligocene‐early Miocene during the Alpine orogeny and was probably enhanced by reactivation of inherited Variscan faults. The modeling results confirm the dependence of fold wavelength on convergence rate and hence the strength of the layers of the lithosphere such that fold wavelength is longest for fast convergence rates favoring whole lithosphere folding. Folding is associated with the formation of dominantly pop‐up type mountain ranges in the brittle crust and thickening of the ductile layers in the synforms of the buckle folds by flow. The mountain ranges are represented by upper crustal pop‐ups forming the main topographic relief. The wavelengths of the topographic uplifts, both, in model and nature suggest mechanical decoupling between crust and mantle. Moreover, our modeling results suggest that buckling in Iberia took place under rheological conditions where the lithospheric mantle is stronger than the lower crust. The presence of an indenter, inducing oblique shortening in response to the opening of the King's Trough in the north western corner of the Atlantic Iberian margin controls the spacing and obliquity of structures. This leads to the transfer of the deformation from the moving walls towards the inner part of the model, creating oblique structures in both brittle and ductile layers. The effect of the indenter, together with an increase on the convergence rate produced more complex brittle structures. These results show close similarities to observations on the general shape and distribution of mountain ranges and basins in Iberia, including the Spanish Central System and Toledo Mountains.
miR‐31 modulates dystrophin expression: new implications for Duchenne muscular dystrophy therapy
Authors: Cacchiarelli Davide , Incitti Tania , Martone Julie , Cesana Marcella , Cazzella Valentina , Santini Tiziana , Sthandier Olga , Bozzoni Irene
Published: January 2011

Duchenne muscular dystrophy (DMD)—which is caused by mutations in the dystrophin gene—is one of the most severe myopathies. Among therapeutic strategies, exon skipping allows the rescue of dystrophin synthesis through the production of a shorter but functional messenger RNA. Here, we report the identification of a microRNA—miR‐31—that represses dystrophin expression by targeting its 3′ untranslated region. In human DMD myoblasts treated with exon skipping, we demonstrate that miR‐31 inhibition increases dystrophin rescue. These results indicate that interfering with miR‐31 activity can provide an ameliorating strategy for those DMD therapies that are aimed at efficiently recovering dystrophin synthesis.
Proteome‐wide identification of mycobacterial pupylation targets
Authors: Poulsen Christian , Akhter Yusuf , Jeon Amy Hye‐Won , Schmitt‐Ulms Gerold , Meyer Helmut E , Stefanski Anja , Stühler Kai , Wilmanns Matthias , Song Young‐Hwa
Published: January 2011

Mycobacteria use a unique system for covalently modifying proteins based on the conjugation of a small protein, referred to as prokaryotic ubiquitin‐like protein (PUP). In this study, we report a proteome‐wide analysis of endogenous pupylation targets in the model organism Mycobacterium smegmatis. On affinity capture, a total of 243 candidate pupylation targets were identified by two complementary proteomics approaches. For 41 of these protein targets, direct evidence for a total of 48 lysine‐mediated pupylation acceptor sites was obtained by collision‐induced dissociation spectra. For the majority of these pupylation targets (38 of 41), orthologous genes are found in the M. tuberculosis genome. Interestingly, approximately half of these proteins are involved in intermediary metabolism and respiration pathways. A considerable fraction of the remaining targets are involved in lipid metabolism, information pathways, and virulence, detoxification and adaptation. Approximately one‐third of the genes encoding these targets are located in seven gene clusters, indicating functional linkages of mycobacterial pupylation targets. A comparison of the pupylome under different cell culture conditions indicates that substrate targeting for pupylation is rather dynamic.
High-Throughput Transcriptome Profiling Of Human Mesenchymal Stem Cells Reveals A Role For Wnt/GSK-3 Signaling In Their Hypoimmunomodulation
Authors: Gangenahalli Gurudutta , Satija Neeraj , Afrin Farhat , Tripathi Rajender Prasad
Published: January 2011

Mesenchymal stem cells (MSCs) are gaining importance among clinicians following recent demonstration of safe allogeneic transplantation due to their ability to modulate the immune response. However,the molecular machinery regulating the expression of immunomodulatory factors in MSCs is unknown. We, therefore, inhibited glycogen synthase kinase-3 (GSK-3),a Wnt signaling inhibitor, to elucidate the role of Wnt signaling in mediating immunoregulatory effects of human MSCs using gene expression profiling. Our results highlight enhanced ability of GSK-3 inhibitor (lithium) treated MSCs to evade immune response as a result of decreased expression of immune stimulatory cytokines and chemokines.
Why are coarse-grained force fields too fast? A look at dynamics of four coarse-grained polymers
Authors: Depa Praveen , Chen Chunxia , Maranas Janna K.
Published: January 2011

Coarse-grained models decrease the number of force sites and thus reduce computational requirements for molecular simulation. While these models are successful in describing structural properties, dynamic evolution is faster than the corresponding atomistic simulations or experiments. We consider coarse-grained models for four polymers and one polymer mixture, where accurate dynamics are obtained by scaling to match the mean-squared displacements of the corresponding atomistic descriptions. We show that the required scaling is dictated by local friction and that this scaling is only valid after the onset of continuous motion.
Experimental and theoretical study of two-photon absorption in nitrofuran derivatives: Promising compounds for photochemotherapy
Authors: De Boni L. , Correa D. S. , Silva D. L. , Gonçalves P. J. , Zilio S. C. , Parra G. G. , Borissevitch I. E. , Canuto S. , Mendonca C. R.
Published: January 2011

We report experimental and theoretical studies of the two-photon absorption spectrum of two nitrofuran derivatives: nitrofurantoine, (1-(5-nitro-2-furfurilideneamine)-hidantoine) and quinifuryl, 2-(5′-nitro-2′-furanyl)ethenyl-4-{N-[4′-(N,N-diethylamino)-1′-methylbutyl]carbamoyl} quinoline. Both molecules are representative of a family of 5-nitrofuran-ethenyl-quinoline drugs that have been demonstrated to display high toxicity to various species of transformed cells in the dark. We determine the two-photon absorption cross-section for both compounds, from 560 to 880 nm, which present peak values of 64 GM for quinifuryl and 20 GM for nitrofurantoine (1 GM = 1×10−50cm4.s.photon−1). Besides, theoretical calculations employing the linear and quadratic response functions were carried out at the density functional theory level to aid the interpretations of the experimental results. The theoretical results yielded oscillator strengths, two-photon transition probabilities, and transition energies, which are in good agreement with the experimental data. A higher number of allowed electronic transitions was identified for quinifuryl in comparison to nitrofurantoine by the theoretical calculations. Due to the planar structure of both compounds, the differences in the two-photon absorption cross-section values are a consequence of their distinct conjugation lengths.
Optical Stark spectroscopy of the $\tilde B{}^1A^{\prime \prime} $B̃1A′′(000)←$\tilde X{}^1A^\prime $X̃1A′(000) system of copper hydroxide
Authors: Wang Fang , Steimle Timothy C.
Published: January 2011

The $\tilde B{}^1A^{\prime \prime} $B̃1A′′(000)←$\tilde X{}^1A^\prime $X̃1A′(000) band system of a cold beam of CuOH has been studied field-free and in the presence of a static electric field. The Stark tuning of the low-J levels of the $\tilde X{}^1A^\prime $X̃1A′(000) state were analyzed to give a value of 3.968(32) D for the a-component of the permanent electric dipole moment, μa. An upper limit of 0.3 D for μa($\tilde B{}^1A^{\prime \prime} $B̃1A′′) is established from the lack of observable Stark tuning for the low-J levels of the $\tilde B{}^1A^{\prime \prime} $B̃1A′′(000) state. The experimental value for μa($\tilde X{}^1A^\prime $X̃1A′) is compared to theoretical predictions and other Cu-containing molecules. A molecular orbital correlation diagram is used to rationalize the large change in μa upon excitation. The electronegativity of OH was determined to be 2.81 from a comparison of the determined μa with the experimental μ values for CuF, CuO, and CuS.
Crystal growth investigations of ice/water interfaces from molecular dynamics simulations: Profile functions and average properties
Authors: Razul M. S. Gulam , Kusalik P. G.
Published: January 2011

Attempts to simulate crystal growth of ice from liquid water and to provide a consistent microscopic description of this process have been challenging tasks. In this paper we have adapted our previously developed molecular dynamics simulation methodology to enable the investigation of steady-state directional crystal growth/melting of ice. Specifically, we examine ice/water systems of the (001), (110), and (111) faces of ice Ic and the (0001), $(10\bar 10)$(101¯0), and $(11\bar 20)$(112¯0) faces of ice Ih, where the TIP4P, TIP4P-Ew, and SPC/E water models have been utilized. The influence of different growth/melting conditions (temperature gradients and growth velocities) is investigated. Profile functions of properties of interest across the interface are obtained from nonequilibrium steady-state simulations and provide consistent descriptions of ice/water interfaces. The widths of the various crystallographic faces are found to increase in the apparent order Ic111, Ih0001 < ${\rm Ih}10\bar 10$ Ih 101¯0 < ${\rm Ih}11\bar 20$ Ih 112¯0 < Ic001 < Ic110. The observed growth rates were in agreement with experimental values and the possible dependence on the various faces is explored. The melting temperatures obtained with the present methodology for the different models are in good agreement with estimates from other work.
A partial-propensity formulation of the stochastic simulation algorithm for chemical reaction networks with delays
Authors: Ramaswamy Rajesh , Sbalzarini Ivo F.
Published: January 2011

Several real-world systems, such as gene expression networks in biological cells, contain coupled chemical reactions with a time delay between reaction initiation and completion. The non-Markovian kinetics of such reaction networks can be exactly simulated using the delay stochastic simulation algorithm (dSSA). The computational cost of dSSA scales with the total number of reactions in the network. We reduce this cost to scale at most with the smaller number of species by using the concept of partial reaction propensities. The resulting delay partial-propensity direct method (dPDM) is an exact dSSA formulation for well-stirred systems of coupled chemical reactions with delays. We detail dPDM and present a theoretical analysis of its computational cost. Furthermore, we demonstrate the implications of the theoretical cost analysis in two prototypical benchmark applications. The dPDM formulation is shown to be particularly efficient for strongly coupled reaction networks, where the number of reactions is much larger than the number of species.
The decay mechanism of photoexcited guanine − A nonadiabatic dynamics study
Authors: Barbatti Mario , Szymczak Jaroslaw J. , Aquino Adélia J. A. , Nachtigallová Dana , Lischka Hans
Published: January 2011

Ab initio surface hopping dynamics calculations were performed for the biologically relevant tautomer of guanine in gas phase excited into the first ππ* state. The results show that the complete population of UV-excited molecules returns to the ground state following an exponential decay within ∼220 fs. This value is in good agreement with the experimentally obtained decay times of 148 and 360 fs. No fraction of the population remains trapped in the excited states. The internal conversion occurs in the ππ* state at two related types of conical intersections strongly puckered at the C2 atom. Only a small population of about 5% following an alternative pathway via a nπ* state was found in the dynamics.
Boundary layer charge dynamics in ionic liquid-ionic polymer transducers
Authors: Davidson Jacob D. , Goulbourne N. C.
Published: January 2011

Ionic polymer transducers (IPTs), also known as ionic polymer-metal composites, are soft sensors and actuators which operate through a coupling of microscale chemical, electrical, and mechanical interactions. The use of an ionic liquid as solvent for an IPT has been shown to dramatically increase transducer lifetime in free-air use, while also allowing for higher applied voltages without electrolysis. In this work, we apply Nernst-Planck/Poisson theory to model charge transport in an ionic liquid IPT by considering a certain fraction of the ionic liquid ions as mobile charge carriers, a phenomenon which is unique to ionic liquid IPTs compared to their water-based counterparts. Numerical simulations are performed using the finite element method to examine how the introduction of another pair of mobile ions affects boundary layer charge dynamics, concentration, and charge density distributions in the electric double layer, and the overall charge transferred and current response of the IPT. Due to interactions with the Nafion ionomer, not all of the ionic liquid ions will function as mobile charge carriers; only a certain fraction will exist as “free” ions. The presence of mobile ionic liquid ions in the transducer will increase the overall charge transferred when a voltage is applied, and cause the current in the transducer to decay more slowly. The additional mobile ions also cause the ionic concentration profiles to exhibit a nonlinear dynamic response, characterized by nonmonotonic ionic concentration profiles in space and time. Although the presence of mobile ionic liquid ions increases the overall amount of charge transferred, this additional charge transfer occurs in a somewhat symmetric manner. Therefore, the additional charge transferred due to the ionic liquid ions does not greatly increase the net bending moment of the transducer; in fact, it is possible that ionic liquid ion movement actually decreases the observed bending response. This suggests that an optimal electromechanical conversion efficiency for bending actuation is achieved by using an ionic liquid where only a relatively small fraction of the ionic liquid ions exist as free ions. Conversely, if it is desired to increase the overall amount of charge transferred, an ionic liquid with a large fraction of free ions should be used. These theoretical considerations are found to be in good qualitative agreement with recent experimental results.
A simple methodology for analyzing association effects on response functions via Monte Carlo simulations
Authors: Gómez-Álvarez P. , Dopazo-Paz A. , Romaní L. , González-Salgado D.
Published: January 2011

A simple methodology was developed to analyze association effects on the thermodynamic response functions for a pure self-associated fluid via Monte Carlo simulations. The procedure essentially involves expressing the residual energy and volume of the fluid in terms of these properties for two hypothetical fluids consisting of monomers and associated molecules, respectively. This allows the thermodynamic response functions to be expressed in a perturbative form as a combination of the values for the property in the monomeric fluid and the contribution of association (the perturbative term). The proposed methodology was used to determine both contributions to the isobaric heat capacity and to the temperature and pressure derivatives of the volume for OPLS methanol along the 50 MPa isobar from 220 to 1500 K. Based on the results, both terms exert a substantial influence on the isobaric heat capacity; by contrast, the association term for the volumetric properties is negligible. These results are consistent with those of a previous work involving simulations with the same model under identical thermodynamic conditions but a different approach. They are also compared with others previously reported in context. Moreover, a comprehensive study of the different types of clusters present in the fluid was performed and the results were related to thermodynamic properties. A strong correlation between the heat capacity of the monomeric fluid and this structural analysis was found.
Effects of electrostatic force on piezoelectric materials under high electric field: Impact on GaN-based nanoscale structures
Authors: Rivera Carlos
Published: January 2011

The determination of the electromechanical properties of materials for a parallel-plate capacitor structure is affected by the electrostatic force between their electrodes. The corrections resulting from this electric-field-induced stress are usually assumed to be linked to the quadratic dependence of the strain on the electric field (electrostriction). Here we show by calculations based on thermodynamic grounds for this simple structure that the effect of the electrostatic force on piezoelectric materials can lead to both quadratic and linear corrections through the combination of the piezoelectric coupling and spontaneous polarization. The case of GaN-based capacitor nanoscale structures is presented taking into account the boundary conditions imposed as well as the effect of geometry. The results in this example point to corrections in the piezoelectric and electrostrictive coefficients higher than 0.3 pm V−1 and 2.6×10−22 m2 V−2, respectively.
Crystallographic, magnetic, and electronic structures of ferromagnetic shape memory alloys Ni2XGa (X=Mn,Fe,Co) from first-principles calculations
Authors: Bai J. , Raulot J. M. , Zhang Y. D. , Esling C. , Zhao X. , Zuo L.
Published: January 2011

The crystallographic, magnetic and electronic structures of the ferromagnetic shape memory alloys Ni2XGa (X=Mn, Fe, and Co), are systematically investigated by means of the first–principles calculations within the framework of density functional theory using the VIENNA AB INITIO SOFTWARE PACKAGE. The lattice parameters of both austenitic and martensitic phases in Ni2MnGa have been calculated. The formation energies of the cubic phase of Ni2XGa are estimated, and show a destabilization tendency if Mn atom is substituted by Fe or Co. From Ni2MnGa to Ni2CoGa, the down spin total density of states (DOS) at Fermi level is gradually increasing, whereas that of the up spin part remains almost unchanged. This is the main origin of the difference of the magnetic moment in these alloys. The partial DOS is dominated by the Ni and Mn 3d states in the bonding region below EF. There are two bond types existing in Ni2XGa: one is between neighboring Ni atoms in Ni2MnGa; the other is between Ni and X atoms in Ni2FeGa and Ni2CoGa alloys.
Electronic structure and transport properties of early transition metal tripledeckers
Authors: Das Bidisa , De Raychaudhury Molly
Published: January 2011

The electronic structure and transport properties of the Cp\documentclass[12pt]{minimal}\begin{document}${_2}$\end{document}2BzM\documentclass[12pt]{minimal}\begin{document}${_2}$\end{document}2 (M = Sc, Ti, and V) tripledeckers are studied by spin polarized density functional theory and nonequilibrium Green's function method considering high-spin and low-spin states. Total energy calculations show that the sandwich structured Cp\documentclass[12pt]{minimal}\begin{document}${_2}$\end{document}2BzSc\documentclass[12pt]{minimal}\begin{document}${_2}$\end{document}2 exists in a singlet state with no local magnetic moment on the Sc atoms. Cp\documentclass[12pt]{minimal}\begin{document}${_2}$\end{document}2BzTi\documentclass[12pt]{minimal}\begin{document}${_2}$\end{document}2 in triplet state exists as a distorted tripledecker and is more stable than singlet and quintet states. Cp\documentclass[12pt]{minimal}\begin{document}${_2}$\end{document}2BzV\documentclass[12pt]{minimal}\begin{document}${_2}$\end{document}2 stabilizes in the quintet state with a spin density of 2.4 on each vanadium atom. Hund's coupling plays a vital role in stabilizing the higher multiplets in case of titanium and vanadium clusters. In bigger clusters like Cp\documentclass[12pt]{minimal}\begin{document}${_3}$\end{document}3Bz\documentclass[12pt]{minimal}\begin{document}$_2$\end{document}2M\documentclass[12pt]{minimal}\begin{document}${_4}$\end{document}4, Sc multidecker has one unpaired spin, Ti multidecker has five unpaired spins, and V multidecker has seven unpaired spins in total. Spin polarized electronic transport is found for all states of vanadium tripledecker and one state of the titanium tripledecker when connected to a gold two probe junction. Moderate to high-spin filter efficiencies are calculated for these states. Cp\documentclass[12pt]{minimal}\begin{document}${_2}$\end{document}2BzSc\documentclass[12pt]{minimal}\begin{document}${_2}$\end{document}2 shows spin-independent electronic transport for all electronic states when introduced in the gold two probe junction. Current versus voltage curves are reported for selected clusters in the two probe setup.
On the polarity of GaN micro- and nanowires epitaxially grown on sapphire (0001) and Si(111) substrates by metal organic vapor phase epitaxy and ammonia-molecular beam epitaxy
Authors: Alloing B. , Vézian S. , Tottereau O. , Vennéguès P. , Beraudo E. , Zuniga-Pérez J.
Published: January 2011

The polarity of GaN micro- and nanowires grown epitaxially by metal organic vapor phase epitaxy on sapphire substrates and by molecular-beam epitaxy, using ammonia as a nitrogen source, on sapphire and silicon substrates has been investigated. On Al2O3(0001), whatever the growth technique employed, the GaN wires show a mixture of Ga and N polarities. On Si(111), the wires grown by ammonia-molecular beam epitaxy are almost entirely Ga-polar (around 90%) and do not show inversion domains. These results can be understood in terms of the growth conditions employed during the nucleation stage.
Integer charge transfer states in organic light-emitting diodes: Optical detection of hole carriers at the anode∣organic interface
Authors: Marchetti A. P. , Sassin K. E. , Young R. H. , Rothberg L. J. , Kondakov D. Y.
Published: January 2011

Hole carriers that reside at the anode∣hole-transport-layer (HTL) interface, creating a dipole layer, have been observed in organic light-emitting diode (OLED) and model devices using charge modulation spectroscopic techniques. These interfacial carriers have been observed with various HTL materials and several anode compositions at voltages such that the HTL is reverse-biased. The cation density at an ITO∣CFx∣NPB interface is estimated to be approximately 1×1013/cm2, or approximately 10% of a molecular layer. [NPB is 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl. CFx is a fluorocarbon polymer.] The cations represent the integer charge-transfer states whose presence has been inferred from ultraviolet photoelectron spectroscopy studies of various conductor∣organic interfaces. Anions of an organic hole-injecting material, 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN) were also observed. Conditions near the injecting contacts often determine the electric field profile and drive voltage of an OLED. Elucidation of these conditions is important to a complete understanding and detailed modeling of OLED operation.
Simple unified proofs of four duality theorems
Authors: Rowe D. J. , Repka J. , Carvalho M. J.
Published: January 2011

Duality relationships between the irreps (irreducible representations) of pairs of distinct commuting groups, \documentclass[12pt]{minimal}\begin{document}$G_1$\end{document}G1 and \documentclass[12pt]{minimal}\begin{document}$G_2$\end{document}G2, on Hilbert spaces of interest have long played important roles in the atomic and nuclear shell models. In addition to the well-known Schur–Weyl duality, the most widely used duality relationships are the so-called: unitary–unitary, orthogonal–symplectic (i.e., noncompact symplectic), symplectic–symplectic (compact symplectics), and orthogonal–orthogonal dualities. Proofs of these dualities exist in the literature. But most of them are not readily accessible to physicists or give little insight into how they might be used in practice. This paper presents unified proofs of the above-mentioned dualities based on the explicit construction of states which are simultaneously of extreme weight for the actions of both \documentclass[12pt]{minimal}\begin{document}$G_1$\end{document}G1 and \documentclass[12pt]{minimal}\begin{document}$G_2$\end{document}G2. The proofs expressed in language familiar to physicists are simple, systematic, and provide useful insights.
Phase transition in BaTiO3 nanotube arrays
Authors: Yang Yang , Wang Xiaohui , Sun Changku , Li Longtu
Published: January 2011

Temperature dependence of phase composition and phase transition in the BaTiO3 nanotube arrays were examined by x-ray diffraction and Raman analyses. The BaTiO3 nanotube arrays exhibited a distinct phase transition behavior from −190 to 300 °C. Tetragonal phase was found to coexist with cubic phase in the BaTiO3 nanotube arrays above Curie temperature. The inner stress as well as size effect in the BaTiO3 nanotube arrays is responsible for the diffuse ferroelectric phase transition and the formation of multiphases coexistence at high temperature.
Electromechanical properties of Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 single crystals
Authors: Li Fei , Zhang Shujun , Lin Dabin , Luo Jun , Xu Zhuo , Wei Xiaoyong , Shrout Thomas R.
Published: January 2011

The Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 (PIN-PMN-PT) crystals were studied as function of phase and orientation. The properties, including the Curie temperature TC, ferroelectric-ferroelectric phase transition temperature TR/O-T, coercive field, and piezoelectric/dielectric responses, were systematically investigated with respect to the composition of PIN-PMN-PT crystals. The Curie temperature TC was found to increase from 160 to 220 °C with ferroelectric-ferroelectric phase transition temperature TR-T and TO-T being in the range of 120–105 °C and 105–50 °C, respectively. The piezoelectric activity of PIN-PMN-PT crystals was analyzed by Rayleigh approach. The ultrahigh piezoelectric response for domain engineered [001] (1600–2200 pC/N) and [011] (830–1550 pC/N) crystals was believed to be mainly from the intrinsic contribution, whereas the enhanced level of piezoelectric and dielectric losses at the compositions around morphotropic phase boundaries (MPBs) was attributed to the phase boundaries motion.
Photoluminescence and Raman Scattering in Ag-doped ZnO Nanoparticles
Authors: Zeferino R. Sánchez , Flores M. Barboza , Pal U.
Published: January 2011

Effects of Ag doping on the crystallinity and optical properties of zinc oxide (ZnO) nanoparticles have been studied by x-ray diffraction, diffuse reflectance spectroscopy, micro-Raman, and photoluminescence spectroscopy. It has been observed that while Ag-doping at low concentration improves the optoelectronic properties of ZnO nanostructures, Ag-doping at high concentrations drastically modify the emission behavior and lattice vibrational characteristics of the nanostructures. High Ag content in ZnO nanostructures causes lattice deformation, induces silent vibrational modes in Raman spectra, and reduces excitonic UV emission due to concentration quenching.
Structural and optical properties of InGaN–GaN nanowire heterostructures grown by molecular beam epitaxy
Authors: Limbach F. , Gotschke T. , Stoica T. , Calarco R. , Sutter E. , Ciston J. , Cusco R. , Artus L. , Kremling S. , Höfling S. , Worschech L. , Grützmacher D.
Published: January 2011

InGaN/GaN nanowire (NW) heterostructures grown by plasma assisted molecular beam epitaxy were studied in comparison to their GaN and InGaN counterparts. The InGaN/GaN heterostructure NWs are composed of a GaN NW, a thin InGaN shell, and a multifaceted InGaN cap wrapping the top part of the GaN NW. High-resolution transmission electron microscopy (HRTEM) images taken from different parts of a InGaN/GaN NW show a wurtzite structure of the GaN core and the epitaxial InGaN shell around it, while additional crystallographic domains are observed whithin the InGaN cap region. Large changes in the lattice parameter along the wire, from pure GaN to higher In concentration demonstrate the successful growth of a complex InGaN/GaN NW heterostructure. Photoluminescence (PL) spectra of these heterostructure NW ensembles show rather broad and intense emission peak at 2.1 eV. However, μ-PL spectra measured on single NWs reveal a reduced broadening of the visible luminescence. The analysis of the longitudinal optical phonon Raman peak position and its shape reveal a variation in the In content between 20% and 30%, in agreement with the values estimated by PL and HRTEM investigations. The reported studies are important for understanding of the growth and properties of NW heterostructures suitable for applications in optoelectronics and photovoltaics.
Copper detection utilizing dendrimer and gold nanowire-induced surface plasmon resonance
Authors: Bhattacharya Priyanka , Chen Pengyu , Spano Meredith Newby , Zhu Lin , Ke Pu Chun
Published: January 2011

A new physical scheme is presented for the detection of copper, based on the use of a fluorescently labeled dendrimer anchored on a gold nanowire. Upon light illumination surface plasmon resonance was generated from the gold nanowire, which promoted quenching of the dendrimer fluorescence as a result of the energy transfer between the dendrimer and the copper ions. The monotonic dependence of the fluorescence quenching on copper concentration was exploited to reach a copper detection sensitivity of 2 nM. In addition, the fluorescence of the labeled dendrimers was quenched specifically by copper in a matrix of common metal ions. Using simulations we calculated the enhanced optical near field for a dendrimer-coated gold nanowire illuminated by a TM-polarized plane wave, which provided a physical basis for the sensitive copper detection using the current experimental scheme.
Ultraviolet-laser atom-probe tomographic three-dimensional atom-by-atom mapping of isotopically modulated Si nanoscopic layers
Authors: Moutanabbir Oussama , Isheim Dieter , Seidman David N. , Kawamura Yoko , Itoh Kohei M.
Published: January 2011

Using ultraviolet-laser assisted local-electrode atom-probe (UV-LEAP) tomography, we obtain three-dimensional (3D) atom-by-atom images of isotopically modulated S28i and S30i ultrathin layers having thicknesses in the range of 5–30 nm. The 3D images display interfaces between the different monoisotopic layers with an interfacial width of ∼1.7 nm, thus demonstrating a significant improvement over isotope mapping achievable using secondary-ion mass-spectrometry or even visible laser-assisted atom-probe tomography. This sharpness is attributed to reduced thermal effects resulting from using a highly focused UV laser beam. Our findings demonstrate that UV-LEAP tomography provides the high accuracy needed to characterize, at the subnanometer scale, the emerging isotopically programmed nanomaterials.
Enhanced critical temperature in epitaxial ferroelectric Pb(Zr0.2Ti0.8)O3 thin films on silicon
Authors: Sambri A. , Gariglio S. , Torres Pardo A. , Triscone J.-M. , Stéphan O. , Reiner J. W. , Ahn C. H.
Published: January 2011

The structural and electrical properties of epitaxial Pb(Zr0.2Ti0.8)O3 thin films grown on 2 in. (001) silicon wafers were investigated. Using x-ray diffraction, the lattice behavior of the heterostructure has been studied as a function of temperature, suggesting a 250 °C increase of the Pb(Zr0.2Ti0.8)O3 ferroelectric-paraelectric transition temperature with respect to the bulk value. This significant enhancement of the critical temperature is understood in terms of a two-dimensional clamping effect.
Solution of Dirac equation with spin and pseudospin symmetry for an anharmonic oscillator
Authors: Goudarzi H. , Sohbati M. , Zarrin S.
Published: January 2011

We present the exact solutions of Dirac equation with anharmonic oscillator potential using the Nikiforov–Uvarov method. Taking into account potentials of vector field V(r) and scalar field S(r) in Dirac Hamiltonian, the bound state energy eigenvalues and the corresponding upper and lower two-component spinors of fermion are obtained. These solutions are considered in the framework of the spin and pseudospin symmetry concept.
Photovoltaic characteristics of p-β-FeSi2(Al)/n-Si(100) heterojunction solar cells and the effects of interfacial engineering
Authors: Dalapati G. K. , Liew S. L. , Wong A. S. W. , Chai Y. , Chiam S. Y. , Chi D. Z.
Published: January 2011

Heterojunction solar cells with Al-alloyed polycrystalline p-type β-phase iron disilicide [p-β-FeSi2(Al)] on n-Si(100) were investigated. The p-β-FeSi2(Al) was grown by sputter deposition and rapid-thermal annealing. Photocurrent of ∼1.8 mA/cm2 and open-circuit voltage of ∼63 mV were obtained for p-β-FeSi2(Al)/n-Si(100)/Ti/Al control cells with indium-tin-oxide (ITO) top electrode. Open-circuit voltage increased considerably once thin Al layer was deposited before amorphous-FeSi2(Al) deposition. Furthermore, device performances were found to improve significantly (∼5.3 mA/cm2 and ∼450 mV) by introducing germanium-nitride electron-blocking layer between ITO and p-β-FeSi2(Al). The improvement is attributed to the formation of epitaxial Al-containing p+-Si at p-β-FeSi2(Al)/n-Si(100) interface and suppressed back-diffusion of photogenerated electrons into ITO.
Fe
3
O
4
/
ZnO
: A high-quality magnetic oxide-semiconductor heterostructure by reactive deposition
Authors: Paul M. , Kufer D. , Müller A. , Brück S. , Goering E. , Kamp M. , Verbeeck J. , Tian H. , Van Tendeloo G. , Ingle N. J. C. , Sing M. , Claessen R.
Published: January 2011

We demonstrate the epitaxial growth of Fe3O4 films on ZnO by a simple reactive deposition procedure using molecular oxygen as an oxidizing agent. X-ray photoelectron spectroscopy results evidence that the iron-oxide surface is nearly stoichiometric magnetite. X-ray diffraction results indicate monocrystalline epitaxy and almost complete structural relaxation. Scanning transmission electron micrographs reveal that the microstructure consists of domains which are separated by antiphase boundaries or twin boundaries. The magnetite films show rather slow magnetization behavior in comparison with bulk crystals probably due to reduced magnetization at antiphase boundaries in small applied fields.