bluuebunny/crossref_metadata_2025 huggingface dataset:
Further Evidence That Repeated Checking Leads to Reduced Memory Confidence, Vividness and Detail: New Evidence That Repeated Object Exposure Also Results in Memory Distrust
Authors: Medway Meredith , Jones Mairwen K.
Published: August 2013

Researchers have suggested that distrust in one's memory is both a cause and a consequence of repeated checking. We investigated whether reduced clarity and confidence occurs to an equal degree with repeated object use and repeated checking. In addition, whether decreased memory confidence persists after a delay in checking or use was examined. Participants (N = 113) either repeatedly checked or repeatedly used a virtual stove or a light bulb stimulus (the control stimulus). Significant declines in memory accuracy, confidence, vividness and detail were observed for the experimental compared to the control stimulus. No significant differences in these effects between the checking and exposure conditions were found. A significant increase in state anxiety across pre-, mid- and post-test was found for both conditions. These findings provide further support for the notion that repeated checking can be self-perpetuating due to its impact on memory processes. The findings also suggest that checking is not necessary for these effects to occur as repeated use without checking also results in significant declines in memory accuracy, confidence, vividness and detail. Theoretical and clinical implications are discussed.
Autobiographical Memory in Children and Adolescents With Acute Stress and Chronic Posttraumatic Stress Disorder
Authors: Nixon Reginald D.V. , Ball Shelly-Anne , Sterk Jisca , Best Talitha , Beatty Lisa
Published: August 2013

Children exposed to traumatic events either recently (Study 1) or in the past (Study 2) were administered the Autobiographical Memory Test (AMT). In Study 1 (N= 67), when asked to retrieve memories from the 24-hour period following their trauma, children with higher levels of acute stress disorder symptoms retrieved a greater number of specific memories on the AMT than either children with low acute stress levels or hospital control children; no difference between groups was observed when memories were retrieved from a period that predated their trauma. However, in Study 2 (N= 67) children with posttraumatic stress disorder retrieved fewer specific memories than non-PTSD controls. The two studies represent the first occasions that AMT performance has been examined in acutely traumatised children and in a sample of children stringently diagnosed with PTSD respectively. The findings underscore the need for further prospective research with clinical samples of children who have experienced trauma.
The Common Fears and Their Origins Among Turkish Children and Adolescents
Authors: Serim-Yıldız Begüm , Erdur-Baker Özgür , Bugay Aslı
Published: August 2013

The present study aimed to investigate the common fears and their origins among children and adolescents from different age, gender, and socioeconomic levels (SES). The sample was comprised of 642 females (48.8%) and 673 males (51.2%) with a total of 1,315 participants aged between 8 and 18 (M= 13.15;SD= 3.18). The Fear interview was utilised to examine the common fears and the role of conditioning, modelling and negative information in the development of children's fears. The result showed that the most common fear in Turkey was ‘God’, followed by ‘losing my friends’ and ‘going to Hell’. In addition, the findings revealed that Turkish students are more likely to learn fears by modelling rather than negative information transmission and conditioning. The results also indicated that negative information transmission had a more intensifying effect on the children and adolescents’ existing fear rather than modelling and conditioning. Furthermore, multinomial logistic regression was conducted to examine the effects of age, gender and SES on the origins of fear. Results showed that age and gender were significant predictors of origins of fear.
Transcultural perspectives of sensory phenomena in Arab Muslim patients suffering from obsessive–compulsive disorder
Authors: Abouhendy W. , Jawad S.
Published: August 2013

The manifestations of obsessive–compulsive disorder (OCD) may vary across cultures. This is article discusses six case presentations of Arabic Muslim people suffering from OCD and is closely associated with practising religious rituals which tend to dominate the clinical picture. This is particularly relevant to sensory phenomena, which are often perceived as abnormal perceptions or hallucinations. We conclude that these phenomena are not uncommon in OCD and have relevant cultural, diagnostic and therapeutic issues in some cases.
Processes of Ethnic Interaction and Integration in Ethiopian History: the Case of the Agaw
Authors: Tamrat Taddesse
Published: August 2013

The earliest documents available on the Ethiopian region, in the form of Greek and Ge'ez inscriptions, give a general picture of considerable ethnic and linguistic diversity in a relatively small area of northern Ethiopia. One of the ethnic groups referred to then and subsequently, with remarkable continuity from pre-Aksumite times until the present day, is the Agaw. Different sections of the Agaw seem to have constituted an important part of the population occupying the highland interior of northern Ethiopia from ancient times. In the early days of the gradual formation and consolidation of the Aksumite state, they seem at first to have been peripheral to the process, which was clearly dominated by the Semitic-speaking inhabitants of the area. Later, however, they assumed an increasing importance, so much so that they eventually took over political leadership, establishing the great Zagwe dynasty. The dynasty lasted for about two hundred years, and transmitted the institutions as well as the cultural and historical traditions of Aksum, almost intact, to later generations.

The exact processes of this development cannot be reconstructed for those early days. Instead, this article is a preliminary attempt to understand the integration of the Agaw into the state and society of the Ethiopian empire over hundreds, even thousands of years, by considering a relatively recent period in the history of the Agaw in the northern and north-western parts of Gojjam. The considerable sense of history which the people of this area possess, going back to the time of its conquest and conversion in the seventeenth century, together with the existence of written materials for the period, provide an opportunity to study a particular example of the entry of the Agaw into the civilization of Christian Ethiopia which may throw light upon the more distant past of their ancestors.
A Commentary onLC v Peru: The CEDAW Committee's First Decision on Abortion
Authors: Ngwena Charles G
Published: August 2013

InLC v Peru, the Committee on the Elimination of Discrimination against Women held that Peru was in breach of its obligations under the Convention on the Elimination of All Forms of Discrimination against Women when it denied a 13 year old girl emergency surgery as well as an abortion. This commentary discusses the human rights significance ofLC v Peru, especially in relation to the advancement of abortion jurisprudence in the African region. It is submitted thatLC v Perumakes an important contribution towards the development of abortion laws that are transparent and accountable to women, as well as responsive to equal protection under the law. The duty of states to operationalizeLC v Peruin their domestic law is an innovative juridical resource for reforming abortion laws. This is particularly so in those regions, including the African region, where the continued criminalization of abortion serves as a significant incentive for unsafe, illegal abortion.
In the Beginning of Penderecki'sParadise Lost
Authors: MURPHY SCOTT
Published: August 2013

Instead of using Milton's famous opening lines, librettist Christopher Fry begins the text for Krzysztof Penderecki's operaParadise Lostwith the invocation that opens Book III, which alludes to acts of creation both biblical and literary. While the primordial effects of Penderecki's instrumental introduction to the opera parallel this allusion in easily discernible ways, his melodic lines used within this introduction also parallel this allusion in ways understood using recent theoretical perspectives on the composer's neo-Romantic style. These melodies exhibit a rare feature of paradoxicality, in that they are at once finite and infinite within stylistic constraints. This musical paradox corresponds to notions of paradox in accounts of cosmological creation, in a literary-operatic creation in which the author is character, and in the hypostatic union of the divine and human in Jesus Christ, a union foregrounded more in Fry's and Penderecki's opera than in Milton's original poem.
‘History As it Should Have Been’: Haunts of the Historical Sublime in John Corigliano's and William Hoffman'sThe Ghosts of Versailles
Authors: RENIHAN COLLEEN
Published: August 2013

In John Corigliano's and William Hoffman's operaThe Ghosts of Versailles(1991), generic, musical, and temporal boundaries are dissolved, and historical processes revealed, resulting in a work that performs an operatic rendering of what philosopher Frank Ankersmit has referred to as sublime historical experience. As Marie Antoinette's ghost resolves her trauma by narrativising it in performance, and as music extends and dramatises the experience of the sublime, the audience experiences profoundly the liminal realm that historically-based operas inhabit in their movement between past and present. Indeed, the temporal suspension that is so central to theories of the sublime finds parallels in opera's historical obsession with death, and in music's ability to momentarily blur the boundaries between life and death, and past and present.The Ghosts of Versaillesallows for the audience's relationship to history to be revisited, reconfigured, and in many cases, reconciled, through a haunting of the present in operatic performance.
Édouard Cornaz (1825 – 1911) and his importance as founder of synesthesia research
Authors: Jewanski Jörg , Simner Julia , Day Sean A. , Ward Jamie
Published: August 2013

From what is known today, Georg Sachs is the first documented synesthete in history ( Jewanski, Day, & Ward, 2009 ). His medical dissertation on albinism including a self-description of his own synesthesia was published in 1812. Yet, when did research on synesthesia start? Who was the first researcher? Why and how did he start? What questions did he consider relevant to ask? What answers could he give without established tests? What articles or books did he write? How influential was his work for the next generation of scientists? Which of his theories are still valid in 2012? Édouard Cornaz (1825 – 1911), the first researcher on synesthesia is almost totally forgotten today. This year, 200 years after Sachs, is the best date to remember and dignify the man who is the precursor of all researchers of this phenomenon.
Auswirkung einer Tanzintervention auf Körperkonzept und kognitive Fähigkeiten von regulär entwickelten Kindern
Authors: Studer-Lüthi Barbara , Züger Brigitte
Published: August 2013

Viel Forschung wird betrieben zu Förderungsmöglichkeiten kognitiver Entwicklung von Kindern und Jugendlichen. Wachsende Evidenz weist auf die Wichtigkeit von Bewegung, insbesondere von Tanz. Da tänzerische Aktivitäten zu Musik nicht nur die Motorik, sondern auch Emotionen und viele Aspekte der Persönlichkeit involvieren, wird die Bedeutung des Tanzes auf der individuellen, kognitiven, affektiven und sozialen Ebene gesehen. Die vorliegende Studie wollte die Wirkung einer zeitlich begrenzten, professionell angeleiteten Tanzintervention auf ausgewählte Fähigkeiten verschiedener Ebenen untersuchen. Einundfünfzig Schulkinder wurden rekrutiert und einer Interventions- oder Kontrollgruppe zugeteilt. Während die Kinder der Interventionsgruppe zweimal wöchentlich von einer erfahrenen Tanztherapeutin in theoriegeleiteten Tanzeinheiten angeleitet wurden, verfolgte die Kontrollgruppe den regulären Schulunterricht. Resultate zeigten signifikante Verbesserungen der Interventionsgruppe auf der individuellen Ebene einerseits und auf der kognitiven Ebene andererseits. Die Verbesserung des Körperkonzepts, speziell der Selbstakzeptanz, sowie des räumlichen Vorstellungsvermögens hoben sich bedeutsam von jener der Kontrollgruppe ab und können auf ressourcenfördernde Prozesse der Tanzintervention zurückgeführt werden. Der Artikel endet mit einer Diskussion des Potentials und Implementierungsmöglichkeiten von Tanzinterventionen neben andere kreativen Aktivitäten im Schulprogramm, welche das (körperliche) Selbstkonzept und die kognitive Entwicklung von Kindern fördern und unterstützen können.
Human Resource Managers’ Attitudes Toward Utility Analysis
Authors: König Cornelius J. , Bösch Flurin , Reshef Amir , Winkler Silvan
Published: August 2013

Although utility analysis (UA) could be an important tool to show the utility of human resource (HR) activities, little is known about its usage. Only Macan and Highhouse (1994) showed that it is used by nearly half of the surveyed US industrial/organizational psychologists and HR professionals. As an extended and refined update of this study, we surveyed Swiss HR managers about their UA usage. Furthermore, we tried to replicate the predictors of the attitude toward UA indicated by Macan and Highhouse’s exploratory results, and used previous theorizing to add predictors. The results revealed that only 8% HR managers used UA. The demand for utility information, the plausibility of UA, and the nonuse of other utility approaches were significant predictors.
Leader-Member Exchange and Innovative Behavior
Authors: Schermuly Carsten Christoph , Meyer Bertolt , Dämmer Lando
Published: August 2013

This study investigates the process underlying the relationship between leadership and employees’ innovative workplace behavior. By combining findings from leader-member exchange (LMX) theory and from research on psychological empowerment, we propose that empowerment mediates the effects of LMX on innovative behavior. We tested the proposed process model with a structural equation model based on a time-lagged questionnaire study with a sample of 225 employees. This design allowed us to investigate the proposed effects under control of the temporal stability of innovative behavior. In partial support of the hypotheses, the model revealed a full mediation of LMX on subsequent innovation behavior via psychological empowerment. The indirect effect was significant even when controlling for the stability of innovative behavior over time.
Advances in our understanding of the pathophysiology of Type 1 diabetes: lessons from the NOD mouse
Authors: Jayasimhan Abhirup , Mansour Kristy P. , Slattery Robyn M.
Published: August 2013

T1D (Type 1 diabetes) is an autoimmune disease caused by the immune-mediated destruction of pancreatic β-cells. Studies in T1D patients have been limited by the availability of pancreatic samples, a protracted pre-diabetic phase and limitations in markers that reflect β-cell mass and function. The NOD (non-obese diabetic) mouse is currently the best available animal model of T1D, since it develops disease spontaneously and shares many genetic and immunopathogenic features with human T1D. Consequently, the NOD mouse has been extensively studied and has made a tremendous contribution to our understanding of human T1D. The present review summarizes the key lessons from NOD mouse studies concerning the genetic susceptibility, aetiology and immunopathogenic mechanisms that contribute to autoimmune destruction of β-cells. Finally, we summarize the potential and limitations of immunotherapeutic strategies, successful in NOD mice, now being trialled in T1D patients and individuals at risk of developing T1D.
Consensus for second‐order agent dynamics with velocity estimators via pinning control
Authors: Hu Hong‐xiang , Yu Wenwu , Xuan Qi , Yu Li , Xie Guangming
Published: August 2013

A consensus problem is investigated for a group of second‐order agents with an active leader where the velocity of the leader cannot be measured, and the leader as well as all the agents is governed by the same non‐linear intrinsic dynamics. To achieve consensus in the sense of both position and velocity, a neighbour‐based estimator design approach and a pinning‐controlled algorithm are proposed for each autonomous agent. It is found that all the agents in the group can follow the leader, and the velocity tracking errors of estimators converge to zero asymptotically, without assuming that the interaction topology is strongly connected or contains a directed spanning tree. In terms of the switching topologies between the leader and the followers, similar results are obtained. Finally, these theoretical results are demonstrated by the numerical simulations.
Linear matrix inequality approach to local stability analysis of discrete‐time Takagi–Sugeno fuzzy systems
Authors: Lee Dong Hwan , Joo Young Hoon , Tak Myung Hwan
Published: August 2013

This study deals with the problem of local stability analysis and the computation of invariant subsets of the domain of attraction (DA) for discrete‐time Takagi–Sugeno fuzzy systems. Based on the fuzzy Lyapunov functions, new sufficient conditions and an iterative scheme are proposed in order to prove the local stability and to estimate the DA. The mean value theorem and polytopic type bounds on the gradient of the membership functions are used to consider the relation between the membership functions at samples k and k  + 1. Each step of the iterative procedure consists of linear matrix inequalities (LMIs) or single‐parameter minimisation problems subject to LMI constraints, which are solvable via convex optimisations. Finally, examples compare the proposed conditions with existing tests.
Experimental demonstration for the implant-free In0.53Ga0.47As quantum-well metal-insulator-semiconductor field-effect transistors with ultra-low source/drain resistance
Authors: Liao M.-H. , Chang L. C.
Published: August 2013

In this work, we demonstrate the ultra-low contact resistivity of 6.7 × 10−9 Ω/cm2 by inserting 0.6 nm ZnO between Al and indium gallium arsenide (Si: 1.5 × 1019 cm−3). The metal-insulator-semiconductor tunneling diode with 0.6 nm ZnO exhibits nearly zero (0.03 eV) barrier height. We apply this contact structure on the source/drain of implant-free In0.53Ga0.47As quantum-well metal-oxide-semiconductor field-effect transistors. The excellent on-state performance such as saturation drain current of 3 × 10−4 A/μm and peak transconductance of 1250 μS/μm is obtained which is attributed to the ultra-low source/drain resistance of 190 Ω μm.
BaY2F8 doped with Er3+: An upconverter material for photovoltaic application
Authors: Boccolini A. , Faoro R. , Favilla E. , Veronesi S. , Tonelli M.
Published: August 2013

Fluoride crystals (BaY2F8) doped with Er3+ ions with different doping level have been grown with a home-made Czochralski furnace. A spectroscopic characterization consisting in both absorption and fluorescence measurements were performed in order to investigate the upconversion mechanism occurring when the material is excited with a radiation at 1557 nm. The measured emission spectrum shows a photoluminescence mainly distributed in the Near Infrared (NIR) region at ≃1 μm. The spectral conversion due to the upconversion makes this material suitable for photovoltaic applications, especially if we combine it with a crystalline silicon solar cell. A device made of single face solar cell+upconverter material (PV-UC) was designed and his external quantum efficiency (EQE) at 1557 nm was measured. EQE values of 6.5% and 4.1% were reached under 8.5 W cm–2 power density illumination for the 30%Er3+ and 20%Er3+ samples, respectively.
Density and anomalous thermal expansion of deeply cooled water confined in mesoporous silica investigated by synchrotron X-ray diffraction
Authors: Liu Kao-Hsiang , Zhang Yang , Lee Jey-Jau , Chen Chia-Cheng , Yeh Yi-Qi , Chen Sow-Hsin , Mou Chung-Yuan
Published: August 2013

A synchrotron X-ray diffraction method was used to measure the average density of water (H2O) confined in mesoporous silica materials MCM-41-S-15 and MCM-41-S-24. The average density versus temperature at atmospheric pressure of deeply cooled water is obtained by monitoring the intensity change of the MCM-41-S Bragg peaks, which is directly related to the scattering length density contrast between the silica matrix and the confined water. Within MCM-41-S-15, the pore size is small enough to prevent the crystallization at least down to 130 K. Besides the well-known density maximum at 277 K, a density minimum is observed at 200 K for the confined water, below which a regular thermal expansion behavior is restored. Within MCM-41-S-24 of larger pore size, water freezes at 220.5 K. The average water/ice density measurement in MCM-41-S-24 validated the diffraction method. The anomalous thermal expansion coefficient (αp) is calculated. The temperature at which the αp reaches maximum is found to be pore size independent, but the peak height of the αp maximum is linearly dependent on the pore size. The obtained data are critical to verify available theoretical and computational models of water.
Compressive force generation by a bundle of living biofilaments
Authors: Ramachandran Sanoop , Ryckaert Jean-Paul
Published: August 2013

To study the compressional forces exerted by a bundle of living stiff filaments pressing on a surface, akin to the case of an actin bundle in filopodia structures, we have performed particulate molecular dynamics simulations of a grafted bundle of parallel living (self-assembling) filaments, in chemical equilibrium with a solution of their constitutive monomers. Equilibrium is established as these filaments, grafted at one end to a wall of the simulation box, grow at their chemically active free end, and encounter the opposite confining wall of the simulation box. Further growth of filaments requires bending and thus energy, which automatically limit the populations of longer filaments. The resulting filament sizes distribution and the force exerted by the bundle on the obstacle are analyzed for different grafting densities and different sub- or supercritical conditions, these properties being compared with the predictions of the corresponding ideal confined bundle model. In this analysis, non-ideal effects due to interactions between filaments and confinement effects are singled out. For all state points considered at the same temperature and at the same gap width between the two surfaces, the force per filament exerted on the opposite wall appears to be a function of a rescaled free monomer density \documentclass[12pt]{minimal}\begin{document}$\hat{\rho }_1^{\rm eff}$\end{document}ρ̂1 eff . This quantity can be estimated directly from the characteristic length of the exponential filament size distribution P observed in the size domain where these grafted filaments are not in direct contact with the wall. We also analyze the dynamics of the filament contour length fluctuations in terms of effective polymerization (U) and depolymerization (W) rates, where again it is possible to disentangle non-ideal and confinement effects.
Decomposition-order effects of time integrator on ensemble averages for the Nosé-Hoover thermostat
Authors: Itoh Satoru G. , Morishita Tetsuya , Okumura Hisashi
Published: August 2013

Decomposition-order dependence of time development integrator on ensemble averages for the Nosé-Hoover dynamics is discussed. Six integrators were employed for comparison, which were extensions of the velocity-Verlet or position-Verlet algorithm. Molecular dynamics simulations by these integrators were performed for liquid-argon systems with several different time steps and system sizes. The obtained ensemble averages of temperature and potential energy were shifted from correct values depending on the integrators. These shifts increased in proportion to the square of the time step. Furthermore, the shifts could not be removed by increasing the number of argon atoms. We show the origin of these ensemble-average shifts analytically. Our discussion can be applied not only to the liquid-argon system but also to all MD simulations with the Nosé-Hoover thermostat. Our recommended integrators among the six integrators are presented to obtain correct ensemble averages.
Standoff explosives trace detection and imaging by selective stimulated Raman scattering
Authors: Bremer Marshall T. , Dantus Marcos
Published: August 2013

We introduce a sensitive method for laser based standoff detection of chemicals based on stimulated Raman scattering. Selective excitation of a particular Raman transition is detected by measuring the diffusely reflected laser light from a distant surface. The method simultaneously measures stimulated Raman loss and gain within a single laser shot and is insensitive to the optical properties (reflectivity/absorptivity) of the substrate. We demonstrate the specificity and sensitivity by detecting and imaging nanogram analyte micro-crystals on paper, fabric, and plastic substrates at 1 to 10 m standoff distance using only 10 mW of laser power from a single femtosecond laser.
Anomalous diffusion of water molecules in hydrated lipid bilayers
Authors: Das Jhuma , Flenner Elijah , Kosztin Ioan
Published: August 2013

We present a molecular dynamics (MD) study of the water molecules in a hydrated lipid bilayer. Due to the interactions at the surface of a solvated lipid membrane, the dynamics of the water and lipid molecules are to some degree correlated. In spite of previous efforts reported in the literature, little is known about the time and length scales of these correlations. Here, by employing a 0.1 μs long equilibrium MD simulation of a dimyristoylphosphatidylcholine (DMPC) lipid bilayer, we show that the waters in a hydrated lipid bilayer can be classified into four dynamically connected water layers, and provide a detailed analysis of the water dynamics within these four regions. We also show that there exists a cooperative molecular motion between the hydration waters and the DMPC lipid molecules, and determine the corresponding characteristic time and length scales.
A theoretical study of hydrated molecular clusters of amines and dicarboxylic acids
Authors: Xu Wen , Zhang Renyi
Published: August 2013

Amines and carboxylic acids have been recognized as important precursor species in atmospheric new particle formation. In this study, the interaction between dimethylamine and succinic acid is investigated using Basin Paving Monte Carlo (BPMC) sampling with the classical force field to obtain low energy conformers of dimethylamine and succinic acid hydrated molecular clusters. Geometry optimization and frequency calculations are further performed on the basis of the BPMC results using density functional theory. At standard temperature and pressure, dimethylamine binds to succinic acid with a bonding energy of 14.2 kcal mol−1, smaller than that of dimethylamine with sulfuric acid (21.1 kcal mol−1). Hydration promotes proton transfer from succinic acid to dimethylamine and consequently increases the interaction strength, while proton transfer from sulfuric acid to dimethylamine occurs without hydration. On the other hand, the reactivity of sulfuric acid with dimethylamine decreases with the degree of hydration of sulfuric acid. The free energies of formation for hydrated clusters consisting of dimethylamine and succinic acid reveal that the interaction between amines and dicarboxylic acids likely exerts a synergetic effect on atmospheric aerosol nucleation by formation of aminium carboxylate ion pairs.
Conductance of ferro- and antiferro-magnetic single-atom contacts: A first-principles study
Authors: Tan Zhi-Yun , Zheng Xiao-long , Ye Xiang , Xie Yi-qun , Ke San-Huang
Published: August 2013

We present a first-principles study on the spin dependent conductance of five single-atom magnetic junctions consisting of a magnetic tip and an adatom adsorbed on a magnetic surface, i.e., the Co-Co/Co(001) and Ni-X/Ni(001) (X = Fe, Co, Ni, Cu) junctions. When their spin configuration changes from ferromagnetism to anti-ferromagnetism, the spin-up conductance increases while the spin-down one decreases. For the junctions with a magnetic adatom, there is nearly no spin valve effect as the decreased spin-down conductance counteracts the increased spin-up one. For the junction with a nonmagnetic adatom (Ni-Cu/Ni(001)), a spin valve effect is obtained with a variation of 22% in the total conductance. In addition, the change in spin configuration enhances the spin filter effect for the Ni-Fe/Ni(001) junction but suppresses it for the other junctions.
Ab initio study on the size effect of symmetric and asymmetric ferroelectric tunnel junctions: A comprehensive picture with regard to the details of electrode/ferroelectric interfaces
Authors: Chen W. J. , Zheng Yue , Luo X. , Wang B. , Woo C. H.
Published: August 2013

Ferroelectric size effect of BaTiO3 (BTO) tunnel junctions with metal Pt and/or oxide SrRuO3 (SRO) electrodes has been comprehensively investigated by the first-principle calculations. A vacuum layer is included in the supercell calculations, so that full-relaxation is achieved without artificial constraint on the supercell strains. We have constructed all of ten possible types of tunnel junctions with either symmetric or asymmetric geometries to systematically explore the influence of electrode/ferroelectric interfaces. The characteristics of atomic structure, polarization, charge density, and electrostatic potential for different geometries and sizes are revealed. It is found that the ferroelectric stability of a tunnel junction depends significantly on the details of the two electrode/ferroelectric interfaces, which present specific short- and long-range properties, e.g., local bonding environment, electronic screening, built-in field, etc. Result shows that Pt/BTO interfaces have strong coupling with ferroelectric distortion and thus play more dominant roles than the SRO/BTO interfaces in affecting the ferroelectric stability of the tunnel junctions. Particularly, it is found that Pt2/TiO2 interface can induce collective ferroelectric distortion in the initially non-distorted barrier. With a full-relaxation of the strains, an abnormal enhancement of ferroelectricity by Pt2/BaO interface due to Pt-O bonding effect is demonstrated, where a strong interfacial-bonding-related polarizing field is verified. Also importantly, polarization stability of asymmetric tunnel junctions is found dependent on direction, manifested with the appearing of a new critical thickness, below which the tunnel junction loses polarization bistability. Furthermore, it shows that the local features of a specific electrode/ferroelectric interface (e.g., the interfacial atomic structure, local polarization, charge transfer, and potential step) are well kept in different types of tunnel junctions. By analyzing and summarizing the results, our results suggest that traditional phenomenological models need several modifications in order to quantitatively reproduce the size effect of ferroelectric tunnel junctions. Our study provides a comprehensive picture of the ferroelectric size effect in BTO tunnel junctions as a function of electrode/ferroelectric interfaces and should have valuable implications for future studies and applications.
Fine-tuning of magnetic and microfluidic viscous forces for specific magnetic bead-based immunocomplex formation
Authors: Cornaglia M. , Tekin H. C. , Lehnert T. , Gijs M. A. M.
Published: August 2013

We investigate the working principle of a novel type of microfluidic sandwich immunoassay, as used for the detection of biomarkers. The heterogeneous assay is based on the specific interactions between an array of functionalized superparamagnetic beads and a flow of secondary superparamagnetic beads that carry the antigens and are simultaneously used as detection labels. We identify the main forces governing the immunoassay performance and develop a combined finite element method/analytical model to predict and control these forces. The clue for the improved assay specificity is in the fine-tuning of inter-bead magnetic dipolar and microfluidic viscous forces, which allows strongly reducing non-specific interactions, while enhancing the specific formation of immunocomplexes. We exploit our theoretical model to explain the enhanced sensitivity of magnetic bead-based immunoassay experiments performed in microfluidic chips.
The nature of free O-H stretching in water adsorbed on carbon nanosystems
Authors: Politano Antonio , Chiarello Gennaro
Published: August 2013

Motivated by the existence of several recent works claiming for unusual hydrogen bonds in water adsorbed or confined in carbon nanostructures, we have analyzed the nature of a sharp O-H stretching at 3700 cm−1 in H2O/graphene recorded in vibrational measurements. The interpretation of such mode is rather controversial. On the basis of a careful inspection of our spectroscopic data and of literature, we suggest that the interpretation of this feature as a fingerprint of surface hydrophobicity, electronic effects or disorder is astray. Instead, it merely arises from interface effects.
On the nonlocal properties of relativistic ponderomotive force
Authors: Iwata Natsumi , Kishimoto Yasuaki
Published: August 2013

A theory of relativistic ponderomotive force of transversely localized laser fields is presented by taking into account the nonlocal effects that correspond to higher order terms of the expansion parameter ϵ≡l/L, i.e., the ratio between particle excursion length and scale length of the field amplitude gradient, while the existing local theory is the first order of ϵ. As a method for preserving the Hamiltonian structure up to higher orders, we employ the variational principle in noncanonical phase space coordinates incorporated with the Lie transformation. By finding noncanonical coordinates and gauges, we obtain a new formula for the ponderomotive force that involves new terms in the third order represented by the second and third spatial derivatives. The force then depends not only on the local field gradient but also on the curvature and its variation which represent the effects of higher-order nonlocal particle motion. The higher-order terms are found to be subject to the symmetry of the field structure. The obtained formula is accessible to the regime in which the higher derivatives of the field amplitude regulate the interaction. We have applied the formula to laser fields exhibiting flat-top super Gaussian and concave hollow transverse structures which are effective in maintaining the long time scale interaction. The associated nonlocal effects are found to play a key role in determining the interactions. Comparison with the direct integration of the particle orbit demonstrates the validity of the derived formula.
Morphological stability of Cu-Nb nanocomposites under high-energy collision cascades
Authors: Zhang Liang , Demkowicz Michael J.
Published: August 2013

We use molecular dynamics and phase field simulations to demonstrate that Cu-Nb multilayered nanocomposites with individual layer thicknesses above 2–4 nm remain morphologically stable when subjected to 100 keV collision cascades, characteristic of neutron or heavy ion irradiation. The probability of morphological instability rapidly increases as the layer thickness decreases to 1 nm, which we attribute to overlap of zones of liquid-like interdiffusion inside radiation-induced thermal spikes at neighboring interfaces in the multilayer.
Arbitrary amplitude solitary and shock waves in an unmagnetized quantum dusty electron-positron-ion plasma
Authors: Rouhani M. R. , Akbarian A. , Mohammadi Z.
Published: August 2013

The behavior of quantum dust ion acoustic soliton and shocks in a plasma including inertialess quantum electrons and positrons, classical cold ions, and stationary negative dust grains are studied, using arbitrary amplitude approach. The effect of dissipation due to viscosity of ions is taken into account. The numerical analysis of Sagdeev potential for small value of quantum diffraction parameter (H) shows that for chosen plasma, only compressive solitons can exist and the existence domain of this type of solitons is decreased by increasing dust density (d). Additionally, the possibility of propagation of both subsonic and supersonic compressive solitons is investigated. It is shown that there is a critical dust density above which only supersonic solitons are observed. Moreover, increasing d leads to a reduction in the existence domain of compressive solitons and the possibility of propagation of rarefactive soliton is provided. So, rarefactive solitons are observed only due to the presence of dust particles in this model quantum plasma. Furthermore, numerical solution of governed equations for arbitrary amplitude shock waves has been investigated. It is shown that only compressive large amplitude shocks can propagate. Finally, the effects of plasma parameters on these structures are investigated. This research will be helpful in understanding the properties of dense astrophysical (i.e., white dwarfs and neutron stars) and laboratory dusty plasmas.
Instabilities in a simplified Fermi-like model with Krook-type collisions, intrinsic damping, and a source
Authors: Zaleśny J.
Published: August 2013

Plasma micro-instabilities have been investigated numerically using a simplified Fermi-like model extended to include also a Krook-type collision operator containing a source plus collisions and a phenomenologically introduced intrinsic damping. In this simplified Fermi-like model, the wave is modeled as a single potential well. The resonant wave-particle interaction occurs due to bounces of the particles trapped between the well barriers, the height of which depends on the energy exchange between the particles and the wave. A fast numerical algorithm is used for solving the simplified Fermi-like model with the source and the relaxation processes and is briefly described and the obtained numerical results are presented and discussed. The main observation is that the presence of the source and the Krook-type collisions tends to suppress the process of filamentation in phase space and to restore the initial distribution function with free energy. In the Fermi like model including source and collisions, the steady state of the wave amplitude is achieved only due to the presence of the damping in the system. This is different from the collisionless case, when the steady state is achieved due to phase mixing. Some remarks in the end of the paper compare the results of the Fermi-like model with those of the analytical Berk-Breizman model, which inspired the extension of the Fermi-like model to include a source, collisions, and damping.
On the gravitational potential of modified Newtonian dynamics
Authors: Núñez Manuel
Published: August 2013

The mathematical structure of the Poisson equation of Modified Newtonian Dynamics (MOND) is studied. The appropriate setting turns out to be an Orlicz-Sobolev space whose Orlicz function is related to Milgrom's μ-function, where there exists existence and uniqueness of weak solutions. Since these do not have in principle much regularity, a further study is performed where the gravitational field is not too large, where MOND is most relevant. In that case the field turns out to be Hölder continuous. Quasilinear MOND is also analyzed.
Direct ion flux measurements at high-pressure-depletion conditions for microcrystalline silicon deposition
Authors: Bronneberg A. C. , Kang X. , Palmans J. , Janssen P. H. J. , Lorne T. , Creatore M. , van de Sanden M. C. M.
Published: August 2013

The contribution of ions to the growth of microcrystalline silicon thin films has been investigated in the well-known high-pressure-depletion (HPD) regime by coupling thin-film analysis with plasma studies. The ion flux, measured by means of a capacitive probe, has been studied in two regimes, i.e., the amorphous-to-microcrystalline transition regime and a low-to-high power regime; the latter regime had been investigated to evaluate the impact of the plasma power on the ion flux in collisional plasmas. The ion flux was found not to change considerably under the conditions where the deposited material undergoes a transition from the amorphous to the microcrystalline silicon phase; for solar-grade material, an ion-to-Si deposition flux of ∼0.30 has been determined. As an upper-estimation of the ion energy, a mean ion energy of ∼19 eV has been measured under low-pressure conditions (<1 mbar) by means of a retarding field energy analyzer. Combining this upper-estimate with an ion per deposited Si atom ratio of ∼0.30, it is concluded that less than 6 eV is available per deposited Si atom. The addition of a small amount of SiH4 to an H2 plasma resulted in an increase of the ion flux by about 30% for higher power values, whereas the electron density, deduced from optical emission spectroscopy analysis, decreased. The electron temperature, also deduced from optical emission spectroscopy analysis, reveals a slight decrease with power. Although the dominant ion in the HPD regime is SiH3+, i.e., a change from H3+ in pure hydrogen HPD conditions, the measured larger ion loss can be explained by assuming steeper electron density profiles. These results, therefore, confirm the results reported so far: the ion-to-Si deposition flux is relatively large but has neither influence on the microcrystalline silicon film properties nor on the phase transition. Possible explanations are the reported high atomic hydrogen to deposition flux ratio, mitigating the detrimental effects of an excessive ion flux.
Electronic states in hybrid boron nitride and graphene structures
Authors: Zhao M. , Huang Y. H. , Ma F. , Hu T. W. , Xu K. W. , Chu Paul K.
Published: August 2013

The energy bands and electronic states of hybrid boron nitride (BN) and graphene structures are studied by first principle calculations. The electronic states change from semi-metallic to insulating depending on the number of B and N atoms as well as domain symmetry. When there are unequal numbers of B and N atoms, mid-gap states usually appear around the Fermi level and the corresponding hybrid structure possesses magnetic and semi-metallic properties. However, when the numbers of B and N atoms are equal, a band gap exists indicative of a semiconducting or insulating nature which depends on the structural symmetry.
Optimization of the detection coil of high-Tc superconducting quantum interference device-based nuclear magnetic resonance for discriminating a minimum amount of liver tumor of rats in microtesla fields
Authors: Chen Hsin-Hsien , Huang Kai-Wen , Yang Hong-Chang , Horng Herng-Er , Liao Shu-Hsien
Published: August 2013

This study presents an optimization of the detection coil of high-Tc superconducting quantum interference device (SQUID)-based nuclear magnetic resonance (NMR) in microtesla fields for discriminating a minimum amount of liver tumor in rats by characterizing the longitudinal relaxation rate, T1−1, of tested samples. The detection coil, which was coupled to the SQUID through a flux transformer, was optimized by varying the copper wires’ winding turns and diameters. When comparing the measured NMR signals, we found that the simulated NMR signal agrees with simulated signals. When discriminating liver tumors in rats, the averaged longitudinal relaxation rate was observed to be T1−1 = 3.3 s−1 for cancerous liver tissue and T1−1 = 6.6 s−1 for normal liver tissue. The results suggest that it can be used to successfully discriminate cancerous liver tissue from normal liver tissues in rats. The minimum amount of samples that can be detected is 0.2 g for liver tumor and 0.4 g for normal liver tissue in 100 μT fields. The specimen was not damaged; it can be used for other pathological analyses. The proposed method provides more possibilities for examining undersized specimens.
Effect of etching with cysteamine assisted phosphoric acid on gallium nitride surface oxide formation
Authors: Wilkins S. J. , Paskova T. , Ivanisevic A.
Published: August 2013

In-situ functionalization of polar GaN was performed by adding cysteamine to a phosphoric acid etchant in order to study its effect on photoluminescence and oxide formation on the surfaces. The functionalization was characterized by atomic force microscopy, x-ray photoelectron spectroscopy, photoluminescence (PL), and water contact angle measurements. Two sets of polar GaN samples with different dislocation densities were evaluated, thin GaN layers residing on sapphire and thick free-standing GaN separated from sapphire substrate aiming to reveal the effect of material quality on in-situ functionalization. The addition of cysteamine to the phosphoric acid solution was found to result in: (i) decreased surface roughness, (ii) no change to hydrophobicity, (iii) decreased oxygen content especially at high-temperature treatments. The effect of the in-situ functionalization on the PL efficiency was more pronounced in the free-standing sample than in the film residing on the sapphire, which was attributed to a higher crystal quality free from strain.
Fermi level influence on the adsorption at semiconductor surfaces—ab initio simulations
Authors: Krukowski Stanisław , Kempisty Paweł , Strąk Paweł
Published: August 2013

Chemical adsorption of the species at semiconductor surfaces is analyzed showing the existence of the two contributions to adsorption energy: bond creation and charge transfer. It is shown that the energy of quantum surface states is affected by the electric field at the surface, nevertheless, the potential contribution of electron and nuclei cancels out. The charge transfer contribution is Fermi level independent for pinned surfaces. Thus for Fermi level pinned at the surface, the adsorption energy is independent on the Fermi energy, i.e., the doping in the bulk. The DFT simulations of adsorption of hydrogen at clean GaN(0001) and silicon at SiC(0001) surfaces confirmed independence of adsorption energy on the doping in the bulk. For the Fermi level nonpinned surfaces, the charge contribution depends on the position of Fermi level in the bulk. Thus adsorption energy is sensitive to change of the Fermi energy in the bulk, i.e., the doping. The DFT simulations of adsorption of atomic hydrogen at 0.75 ML hydrogen covered GaN(0001) surface confirmed that the adsorption energy may be changed by about 2 eV by the doping change from n- to p-type.
A multi-scale modeling of junctionless field-effect transistors
Authors: Yam ChiYung , Peng Jie , Chen Quan , Markov Stanislav , Huang Jun Z. , Wong Ngai , Cho Chew Weng , Chen GuanHua
Published: August 2013

In this work, we simulate a realistic junctionless (JL) field-effect transistor using a multi-scale approach. Our approach features a combination of the first-principles atomistic calculation, semi-classical semiconductor device simulation, compact model generation, and circuit simulation. The transfer characteristics of JL transistors are simulated by a recently developed quantum mechanical/electromagnetics method, and good agreement is obtained compared to experiment. A compact model for JL transistors is then generated for subsequent circuit simulation. We demonstrate a multi-scale modeling framework for quantum mechanical effects in nano-scale devices for next generation electronic design automation.
Measurements of the eigenfunction of reversed shear Alfvén eigenmodes that sweep downward in frequency
Authors: Heidbrink W. W. , Austin M. E. , Spong D. A. , Tobias B. J. , Van Zeeland M. A.
Published: August 2013

Reversed shear Alfvén eigenmodes (RSAEs) usually sweep upward in frequency when the minimum value of the safety factor qmin decreases in time. On rare occasions, RSAEs sweep downward prior to the upward sweep. Electron cyclotron emission measurements show that the radial eigenfunction during the downsweeping phase is similar to the eigenfunction of normal, upsweeping RSAEs.