bluuebunny/crossref_metadata_2025 huggingface dataset:
Can we build it: formal synthesis of control strategies for cooperative driver assistance systems
Authors: DAMM WERNER , PETER HANS-JÖRG , RAKOW JAN , WESTPHAL BERND
Published: July 2013

We propose a design and verification methodology supporting the early phases of system design for cooperative driver assistance systems, focusing on the realisability of new automotive functions. Specifically, we focus on applications where drivers are supported in complex driving tasks by safe strategies involving the coordinated movements of multiple vehicles to complete the driving task successfully. We propose a divide and conquer approach for formally verifying timed probabilistic requirements on successful completion of the driving task and collision freedom based on formal specifications of a set of given manoeuvring and communication capabilities of the car. In particular, this allows an assessment of whether they are sufficient to implement strategies for successful completion of the driving task.
A modular formal semantics for Ptolemy
Authors: TRIPAKIS STAVROS , STERGIOU CHRISTOS , SHAVER CHRIS , LEE EDWARD A.
Published: July 2013

Ptolemy‡is an open-source and extensible modelling and simulation framework. It offers heterogeneous modeling capabilities by allowing different models of computation, both untimed and timed, to be composed hierarchically in an arbitrary fashion. This paper proposes a formal semantics for Ptolemy that is modular in the sense that atomic actors and their compositions are treated in a unified way. In particular, all actors conform to an executable interface that contains four functions: fire (produce outputs given current state and inputs); postfire (update state instantaneously); deadline (how much time the actor is willing to let elapse); and time-update (update the state with the passage of time). Composite actors are obtained using composition operators that in Ptolemy are called directors. Different directors realise different models of computation. In this paper, we formally define the directors for the following models of computation: synchronous- reactive, discrete event, continuous time, process networks and modal models.
Cor triatriatum with a left upper anomalous pulmonary venous return to the innominate vein
Authors: Galoin-Bertail Claire , Gouton Marielle
Published: July 2013

Cor triatriatum sinister is an uncommon congenital cardiac anomaly accounting for 0.1% of all congenital cardiac malformations, with an anomalous venous return being a frequently associated condition. We present the case of a 14-year-old girl misdiagnosed as having an atrial septal defect with pulmonary hypertension who actually had a cor triatriatum with a left upper anomalous pulmonary venous return to the innominate vein.
STRUCTURAL EQUATIONS AND BEYOND
Authors: HUBER FRANZ
Published: July 2013

Recent accounts of actual causation are stated in terms of extended causal models. These extended causal models contain two elements representing two seemingly distinct modalities. The first element are structural equations which represent the “(causal) laws” or mechanisms of the model, just as ordinary causal models do. The second element are ranking functions which represent normality or typicality. The aim of this paper is to show that these two modalities can be unified. I do so by formulating two constraints under which extended causal models with their two modalities can be subsumed under so called “counterfactual models” which contain just one modality. These two constraints will be formally precise versions of Lewis’ (1979) familiar “system of weights or priorities” governing overall similarity between possible worlds.
The effects of low-moderate dose prenatal ethanol exposure on the fetal and postnatal rat lung
Authors: Probyn M. E. , Cuffe J. S. M. , Zanini S. , Moritz K. M.
Published: July 2013

Little is known about whether exposure of the fetus to alcohol alters pulmonary development or function. This study aimed to determine whether low-moderate ethanol (EtOH) exposure throughout gestation alters structural and non-respiratory functional aspects of the fetal and postnatal lung. Sprague–Dawley rats were fed an ad libitum liquid diet ±6% v/v EtOH daily throughout pregnancy, achieving a plasma ethanol (EtOH) concentration of 0.03%. Gene and protein expression was determined in pulmonary tissue collected from fetuses at embryonic day (E) 20 and adult offspring. The percentage of airspace and alveolar size was measured in pulmonary tissue collected at postnatal day (PN) 1. At E20, EtOH-exposed fetuses had decreased aquaporin 5 mRNA levels and a non-significant trend for decreased epithelial sodium channel type α; expression of other pulmonary fluid homeostatic and development genes and surfactant protein genes were not different between groups. At PN1, there was no difference between EtOH-exposed and control offspring in the distal airspace percentage or diameter. At 8 months, collagen type III α1 gene expression was upregulated in EtOH-exposed male offspring; this was associated with increased collagen deposition at 10 months. At 19 months, male EtOH-exposed offspring had a 25% reduction in the protein levels of surfactant protein B. The alterations observed in male EtOH-exposed offspring suggest chronic low-moderate prenatal EtOH-exposure during development may result in increased pulmonary fibrosis. Such an alteration would decrease the respiratory capacity of the lung.
A Personality Framework for the Unification of Psychology
Authors: Mayer John D. , Allen Jayne L.
Published: July 2013

We describe the Personality Systems Framework for organizing the discipline of psychology ( J. D. Mayer, 2005 , A tale of two visions: Can a new view of personality help integrate psychology? American Psychologist, Vol. 60, 294–307). The framework consists of a broad outline of topics that psychologists already research, along with a map of psychology's location in relation to other systems of scientific study and a map of its inner psychological functions, such as “energy development” and “knowledge guidance,” which organize interrelated areas of research. The Systems Framework uncovers an organization that already is in partial use by psychologists, elucidates it, and uses an expanded version of the approach to better organize the field's major topics. Examples of how the Personality Systems Framework can be applied to education, research, and translational work are provided.
Comparative Psychology as Unified Psychology: The Case of Curiosity and Other Novelty-Related Behavior
Authors: Pisula Wojciech , Turlejski Krzysztof , Charles Eric P.
Published: July 2013

The comparative study of human and nonhuman animals covers the full range of psychological phenomenon, and so comparative psychology already exists as a form of general psychology. The potential of comparative psychology to bring together many aspects of the field of psychology is illustrated through a review of studies exploring curiosity in a variety of species. The issue of an organism's response to novelty was recognized as an important research subject in the era of Darwin. Since that time, considerable empirical and theoretical material on various aspects of behavior associated with new stimuli has been accumulated. This research additionally illustrates the utility of integrative levels theory, which enables a multilevel, comprehensive analysis of behavior. Comparative psychologists played important roles in the history of most of psychology's subdisciplines, and present-day comparative psychologists continue to contribute insights into a startlingly broad range of psychological phenomenon. Further, appreciation for the higher-level research program provided by comparative work provides a larger context that helps ground the study of human psychology.
A Natural Science of Behavior
Authors: Catania A. Charles
Published: July 2013

We are evolved organisms, and our selection in that evolution depended on what our ancestors were able to do. Behavior should not be viewed as a symptom of something else, such as mind or brain; it is worthy of study in its own right. Psychology these days is like a biology without natural selection. The argument here is that psychology as a science cannot survive other than as a science of behavior. The selection of behavior by its consequences is not universal but it is pervasive. This selection, one aspect of which is called reinforcement, is a central component of a science of behavior. Reinforcement is a phenomenon, not a theory. Yet even this most fundamental of behavioral processes is too often misconstrued, misrepresented and even disowned by some psychologists. Misuse of extinction and the myth of hidden costs of reward provide two examples. The selection of behavior by its consequences was as significant a development in the science of the 20th century as Darwin's account of evolution in terms of natural selection in the 19th. In addition to phylogenic and cultural selection, language necessarily involves a third variety, cultural selection. The selection of verbal behavior, as it is passed on among individuals, is an essential dimension of human behavior. Critiques of behavioral accounts of language have typically conflated questions about language structure with those about its functions. Treating language as verbal behavior brings it within the purview of a unified account of human action.
Structure, Caregiver–Child Interactions, and Children’s General Physical and Behavioral Development in Three Central American Institutions
Authors: Groark Christina J. , McCall Robert B. , McCarthy Stephanie K. , Eichner Joan C. , Gee Amy D.
Published: July 2013

This article describes structural characteristics and caregiver–child interactions ( N = 34) in three Central American institutions for infants and young children ( N = 79) and relates differences in these characteristics to differences in children’s physical, behavioral, and cognitive development. Generally, the institution with the smallest group size, fewest children per caregiver, and a few consistent caregivers had children with the best physical, behavioral, and cognitive development; this institution also had many temporary volunteers who played with the children. Differences in the quality of caregiver–child interactions were not directly related to children’s development, but the potential benefit of high-quality interactions may have been minimized by a high children:caregiver ratio in one institution, and the presence of volunteers to play with children may have compensated for and/or minimized the display of higher-quality interactions by staff caregivers in another institution.
Minimal 2-dominating sets in trees
Authors: Krzywkowski Marcin
Published: July 2013

We provide an algorithm for listing all minimal 2-dominating sets of a tree of ordernin time 𝒪(1.3248n). This implies that every tree has at most 1.3248nminimal 2-dominating sets. We also show that this bound is tight.
Operator product expansion algebra
Authors: Holland Jan , Hollands Stefan
Published: July 2013

We establish conceptually important properties of the operator product expansion (OPE) in the context of perturbative, Euclidean φ4-quantum field theory. First, we demonstrate, generalizing earlier results and techniques of hep-th/1105.3375, that the 3-point OPE, \documentclass[12pt]{minimal}\begin{document}$\langle {\mathcal {O}}_{A_{1}}{\mathcal {O}}_{A_{2}}{\mathcal {O}}_{A_{3}} \rangle = \sum _{C}{\cal C}_{A_{1}A_{2}A_{3}}^{C}\langle {\mathcal {O}}_{C}\rangle$\end{document}⟨OA1OA2OA3⟩=∑CCA1A2A3C⟨OC⟩, usually interpreted only as an asymptotic short distance expansion, actually converges at finite, and even large, distances. We further show that the factorization identity \documentclass[12pt]{minimal}\begin{document}${\cal C}_{A_{1}A_{2}A_{3}}^{B}=\sum _{C}{\cal C}_{A_{1}A_{2}}^{C}{\cal C}_{CA_{3}}^{B}$\end{document}CA1A2A3B=∑CCA1A2CCCA3B is satisfied for suitable configurations of the spacetime arguments. Again, the infinite sum is shown to be convergent. Our proofs rely on explicit bounds on the remainders of these expansions, obtained using refined versions, mostly due to Kopper et al., of the renormalization group flow equation method. These bounds also establish that each OPE coefficient is a real analytic function in the spacetime arguments for non-coinciding points. Our results hold for arbitrary but finite loop orders. They lend support to proposals for a general axiomatic framework of quantum field theory, based on such “consistency conditions” and akin to vertex operator algebras, wherein the OPE is promoted to the defining structure of the theory.
Accurate basis set truncation for wavefunction embedding
Authors: Barnes Taylor A. , Goodpaster Jason D. , Manby Frederick R. , Miller Thomas F.
Published: July 2013

Density functional theory (DFT) provides a formally exact framework for performing embedded subsystem electronic structure calculations, including DFT-in-DFT and wavefunction theory-in-DFT descriptions. In the interest of efficiency, it is desirable to truncate the atomic orbital basis set in which the subsystem calculation is performed, thus avoiding high-order scaling with respect to the size of the MO virtual space. In this study, we extend a recently introduced projection-based embedding method [F. R. Manby, M. Stella, J. D. Goodpaster, and T. F. Miller III, J. Chem. Theory Comput. 8, 2564 (2012)]10.1021/ct300544e to allow for the systematic and accurate truncation of the embedded subsystem basis set. The approach is applied to both covalently and non-covalently bound test cases, including water clusters and polypeptide chains, and it is demonstrated that errors associated with basis set truncation are controllable to well within chemical accuracy. Furthermore, we show that this approach allows for switching between accurate projection-based embedding and DFT embedding with approximate kinetic energy (KE) functionals; in this sense, the approach provides a means of systematically improving upon the use of approximate KE functionals in DFT embedding.
Experimental investigation of the wall shear stress in a circular impinging jet
Authors: El Hassan M. , Assoum H. H. , Martinuzzi R. , Sobolik V. , Abed-Meraim K. , Sakout A.
Published: July 2013

The influence of the large-scale vortical structures on the wall shear stress in a circular impinging jet is investigated experimentally for a Reynolds number of 1260. Time-resolved particle image velocimetry and polarographic measurements are performed simultaneously. It is found that the instantaneous wall shear stress is strongly dependent on the vortex dynamics, particularly for different parts of the transverse vortex. The influence of the vortex ring, the secondary and tertiary vortices on the ejection/sweep process near the wall is the main mechanism involved in the wall shear stress variation. In the region of the boundary layer separation, the wall shear stress amplitude increases just upstream of the separation and dramatically decreases in the recirculation zone downstream from the separation. The interaction between primary and secondary structures and their pairing process with the tertiary structure affects the sweep/ejection process near the wall and subsequently the wall shear stress variation. A comparison between the Finite Time Lyapunov Exponent (FTLE) method and the phase average technique is performed. It is shown that both methods describe the flow dynamics in the impinging region of the vortex ring. However, the FTLE method is more suitable for describing the unsteady separation of the boundary layer.
Design and performance of tapered cubic anvil used for achieving higher pressure and larger sample cell
Authors: Han Qi-Gang , Yang Wen-Ke , Zhu Pin-Wen , Ban Qing-Chu , Yan Ni , Zhang Qiang
Published: July 2013

In order to increase the maximum cell pressure of the cubic high pressure apparatus, we have developed a new structure of tungsten carbide cubic anvil (tapered cubic anvil), based on the principle of massive support and lateral support. Our results indicated that the tapered cubic anvil has some advantages. First, tapered cubic anvil can push the transfer rate of pressure well into the range above 36.37% compare to the conventional anvil. Second, the rate of failure crack decreases about 11.20% after the modification of the conventional anvil. Third, the limit of static high-pressure in the sample cell can be extended to 13 GPa, which can increase the maximum cell pressure about 73.3% than that of the conventional anvil. Fourth, the volume of sample cell compressed by tapered cubic anvils can be achieved to 14.13 mm3 (3 mm diameter × 2 mm long), which is three and six orders of magnitude larger than that of double-stage apparatus and diamond anvil cell, respectively. This work represents a relatively simple method for achieving higher pressures and larger sample cell.
Three dimensional flow structures in a moving droplet on substrate: A dissipative particle dynamics study
Authors: Li Zhen , Hu Guo-Hui , Wang Zhi-Liang , Ma Yan-Bao , Zhou Zhe-Wei
Published: July 2013

It is of both fundamental and practical interest to study the flow physics in the manipulation of droplets. In this paper, we investigate complex flow in liquid droplets actuated by a linear gradient of wettability using dissipative particle dynamics simulation. The wetting property of the substrate ranging from hydrophilic to hydrophobic is achieved by adjusting the conservative solid-liquid interactions which results in a variation of solid-liquid surface tension. The internal three-dimensional velocity field with transverse flow in droplet is revealed and analyzed in detail. When the substrate is hydrophobic, it is found that there is slight deformation but strong flow circulation inside the droplet, and the droplet rolling is the dominant mechanism for the movement. However, large deformation of the droplet is generated after the droplet reaches the hydrophilic surface, and a mechanism combining rolling and sliding dominates the transportation of the droplet. Another interesting finding is that the thermal fluctuation can accelerate the spontaneous motion of a liquid droplet under a wetting gradient. The effects of the steepness of wetting gradient and the size of droplet on the translation speed are studied as well.
The optical and electrical properties of silver nanowire mesh films
Authors: Khanarian G. , Joo J. , Liu X.-Q. , Eastman P. , Werner D. , O'Connell K. , Trefonas P.
Published: July 2013

We present experimental results for the transmission T, haze H, sheet resistance Rs, and its spatial fluctuations ΔRs for silver nanowire films. Mie light scattering theory of nanowires is developed to predict both T and H as a function of diameter D of wires and the surface fraction ϕs covered by the wires. Percolation theory is used to derive an equation for Rs in terms of D, the aspect ratio of wires D/L and ϕs. The critical exponent t for percolation of Rs is found to be 1.23 in close agreement with theoretical results for 2D random resistive networks (t = 1.3). These equations show the importance of both the distributions of diameter ⟨D⟩ and aspect ratio of wires ⟨D⟩⟨L⟩/⟨L2⟩ to predict the optical and electrical properties. Spatial fluctuations ΔRs/Rs can also be significant in these films and be greater than 10% as ϕs approaches the critical percolation concentration ϕc. We show that the calculated T versus Rs and H versus Rs curves are in good agreement with the experimental data. We propose figures of merit for percolating nanowire films in terms of high T, low H, and low Rs to order the quality of films for touch screen applications. The results show that D < 50 nm and L > 5 μm are needed to achieve low haze H < 1%, high transmission T > 90%, together with low Rs ∼ 100 Ω/sq for touch screen applications. Finally, we present experimental and theoretical results of the real and imaginary refractive indices of AgNW/polymer nanocomposites, and find that the Van De Hulst model is more accurate than the Maxwell Garnett models.
Validation of the trapped charge model of electrowetting contact angle saturation on lipid bilayers
Authors: Kedzierski Jakub T. , Batra Richa , Berry Shaun , Guha Ingrid , Abedian Behrouz
Published: July 2013

The problem of modeling contact angle saturation in electrowetting has resisted a number of concentrated efforts by leading researchers. Several models have been proposed, from charge trapping, to droplet ejection, to thermodynamic instability, but no consensus has been reached as to which model better describes the effect. In this paper, we validate the charge trapping based model of contact angle saturation in electrowetting on lipid bilayers, through careful analysis of charge movement between the liquid charge states and trapped charge states at the solid dielectric interface. We also describe a powerful new methodology for studying electrowetting systems by modeling them with an equivalent circuit and simulating the circuit using the SPICE circuit simulator.
The role of mass removal mechanisms in the onset of ns-laser induced plasma formation
Authors: Autrique D. , Clair G. , L'Hermite D. , Alexiades V. , Bogaerts A. , Rethfeld B.
Published: July 2013

The present study focuses on the role of mass removal mechanisms in ns-laser ablation. A copper sample is placed in argon, initially set at standard pressure and temperature. Calculations are performed for a 6 ns laser pulse with a wavelength of 532 nm and laser fluences up to 10 J/cm2. The transient behavior in and above the copper target is described by a hydrodynamic model. Transmission profiles and ablation depths are compared with experimental results and similar trends are found. Our calculations reveal an interesting self-inhibiting mechanism: volumetric mass removal in the supercritical region triggers plasma shielding and therefore stops proceeding. This self-limiting process indicates that volumetric mass removal does not necessarily result in large ablation depths.
Modeling mechanophore activation within a crosslinked glassy matrix
Authors: Silberstein Meredith N. , Min Kyoungmin , Cremar Lee D. , Degen Cassandra M. , Martinez Todd J. , Aluru Narayana R. , White Scott R. , Sottos Nancy R.
Published: July 2013

Mechanically induced reactivity is a promising means for designing self-reporting materials. Mechanically sensitive chemical groups called mechanophores are covalently linked into polymers in order to trigger specific chemical reactions upon mechanical loading. These mechanophores can be linked either within the backbone or as crosslinks between backbone segments. Mechanophore response is sensitive to both the matrix properties and placement within the matrix, providing two avenues for material design. A model framework is developed to describe reactivity of mechanophores located as crosslinks in a glassy polymer matrix. Simulations are conducted at the molecular and macromolecular scales in order to develop macroscale constitutive relations. The model is developed specifically for the case of spiropyran (SP) in lightly crosslinked polymethylmethacrylate (PMMA). This optically trackable mechanophore (fluorescent when activated) allows the model to be assessed in terms of observed experimental behavior. The force modified potential energy surface (FMPES) framework is used in conjunction with ab initio steered molecular dynamics (MD) simulations of SP to determine the mechanophore kinetics. MD simulations of the crosslinked PMMA structure under shear deformation are used to determine the relationship between macroscale stress and local force on the crosslinks. A continuum model implemented in a finite element framework synthesizes these mechanochemical relations with the mechanical behavior. The continuum model with parameters taken directly from the FMPES and MD analyses under predicts stress-driven activation relative to experimental data. The continuum model, with the physically motivated modification of force fluctuations, provides an accurate prediction for monotonic loading across three decades of strain rate and creep loading, suggesting that the fundamental physics are captured.
Two cases of reciprocal relations for electric and hydrodynamic currents: A rigid polymer in a nano-channel and a polyelectrolyte gel
Authors: Rowghanian Payam , Grosberg Alexander Y.
Published: July 2013

We illustrate an Onsager-type linear response theory of electrohydrodynamic coupling for two examples, namely, a long nano-channel blocked partially by a rigid polymer and a gel of semi-flexible polyelectrolyte chains. We calculate the hydrodynamic and electric currents driven by an external voltage and pressure and the corresponding Onsager coefficients for these systems. Our consideration clarifies the effect of the electro-osmotic flow on the effective charge of the polymer inside the channel. It also makes it possible to explore the dependence of the currents through the gel on the electric screening radius and salt concentration.
A model of a Serbian energy efficient house for decentralized electricity production
Authors: Jovanovic Goran , Zivkovic Dragoljub , Mancic Marko , Stankovic Vladana , Stankovic Danica , Stefanović Velimir , Mitkovic Petar
Published: July 2013

This paper presents architectural project and simulation of energy consumption and production of a model of Energy Efficient House for Decentralized Energy (DE). The house model is designed for the area of Serbia, based on the needs of an average Serbian family. The model is designed to investigate opportunities for DE of typical house geometry with advantages of passive solar architecture combined with active solar systems and heat pump. Simulation of the model was performed for the climate conditions for the city of Nis. Thermal load for designed net-zero energy efficient home for a period of one year was simulated by means of trnsys software. With respect to renewable energy sources in Serbia, production of electrical, heating, and cooling energy by solar photovoltaic/thermal collectors, heat pump, and heat storage is considered. The balance of simulated annual electricity production and consumption show that the house model can produce 51% of its energy demands. Simulation results are used to determine pathways for model modification towards more effective solar harvesting for electricity production.
Trion formation and recombination dynamics in hole-doped single-walled carbon nanotubes
Authors: Nishihara Taishi , Yamada Yasuhiro , Okano Makoto , Kanemitsu Yoshihiko
Published: July 2013

We studied the trion (charged exciton) formation and recombination dynamics in hole-doped (7,5) single-walled carbon nanotubes (SWCNTs) by performing femtosecond transient absorption spectroscopy. The doping of SWCNTs with holes leads to a fast decay component from an exciton to a trion, and the trion decays with a lifetime of a few picoseconds. The experimental results can be explained by a quantized model accounting for the dark exciton and trion states and the hole number distribution in a SWCNT. Our findings show that the optical responses of SWCNTs can be manipulated by doping of SWCNTs with a small number of holes.
Solar ray transfer inside sea-shell stationary trough solar concentrator
Authors: Marjanović V. , Bojić M. , Marjanović N. , Skerlić J.
Published: July 2013

A sea-shell stationary trough solar concentrator for heat production consists of a parabolic, cylindrical trough reflector, a flat double-sided absorber, and a flat aperture. By ray tracing with the software catia, the optical efficiency (the efficiency of solar ray transfer inside the concentrator) is investigated for different solar ray altitudes at the concentrator aperture and different kinds of reflector shells. For the concentrator installed in Kragujevac, Serbia, the highest optical efficiency is obtained for the solar ray altitudes between 45° and 69.75°.
Energy landscape in frustrated systems: Cation hopping in pyrochlores
Authors: Brooks Hinojosa Beverly , Asthagiri Aravind , Nino Juan C.
Published: July 2013

We investigate the dynamics of the local environment and electronic structure in inherently dipolar frustrated pyrochlore compounds to help identify the fundamental nature of dipolar disorder in pyrochlore systems and determine the necessary and sufficient conditions for dielectric relaxation. We map out the energy landscape associated with cation hopping events in three compounds and correlate the hopping pathway with experimental dielectric response. Comprehensive analysis of the calculations allows us to postulate rules to predict the occurrence of relaxation and cation hopping pathways.
Conductivity study on GeS2-Ga2S3-AgI-Ag chalcohalide glasses
Authors: Ren Jing , Yan Qiqi , Wagner Tomas , Zima Vitezslav , Frumar Miloslav , Frumarova Bozena , Chen Guorong
Published: July 2013

A new kind of ion-conducting glasses based on GeS2-Ga2S3-AgI system is prepared. A relatively large amount of silver can be dissolved into this kind of glass system, and the obtained glasses are still transparent in the red part of the visible spectrum. Only a three times increase in the silver concentration can lead to approximately two hundred times increase in the ionic conductivity. The structural contributions to the ionic conductivity of the glasses are discussed. The present glasses show potential to be used as solid state electrolyte.
Visualization of three dimensional domain structures in ferroelectric PbTiO3 nanotubes
Authors: Yoo Hyunjun , Bae Changdeuck , Kim Myungjun , Hong Seungbum , No Kwangsoo , Kim Yunseok , Shin Hyunjung
Published: July 2013

We report visualization of three-dimensional domain structures in ferroelectric PbTiO3 (PTO) nanotubes (NTs) using piezoresponse force microscopy (PFM). The domain distributions of the x, y, and z-axes in PTO NTs were separately measured out-of and in-planes at angles of 0° and 90° by vertical and lateral PFM. The separately obtained PFM images were combined to reconstruct the complex domain structures based on some basic assumptions and finite element modeling. The cross-sectional domain configurations of the PTO NTs were visualized by the proposed approach. The results can provide insight into complex domain configurations of ferroelectric nanostructures.
Influence of quantum and thermal noise on spin-torque-driven magnetization switching
Authors: Wang Yong , Zhou Yan , Zhang Fu-Chun
Published: July 2013

We apply a recently developed quantum theory of spin torque to study the effect of the quantum noise on the magnetization switching. The quantum noise induces considerable fluctuation of the switching time at zero temperature. By including the thermal noise, the temperature dependence of the expectation value and standard deviation of the switching time are obtained, and the results are fitted to an effective first passage model. Our theoretical predictions can be examined in single-shot experiments of spin-torque-driven switching.
Observation of spin-glass behavior in antiperovskite compound Mn3Cu0.7Ga0.3N
Authors: Zhang X. H. , Yuan Q. , Han J. C. , Zhao J. G. , Jian J. K. , Zhang Z. H. , Song B.
Published: July 2013

We present a detailed study of magnetic properties of antiperovsite compound Mn3Cu0.7Ga0.3N. Ac susceptibility measurements show a peak around “freezing temperature” (Tf), with the peak position shifting as a function of the driving frequency f and magnetic field H. Magnetic relaxation measurements show a slow decay of the remanent magnetization with time below Tf. These findings consistently demonstrate the existence of spin-glass states in Mn3Cu0.7Ga0.3N. The behavior may be attributed to either a small amount of disorder, arising from the random occupation of 1a sites in the space group Pm-3m by mixed Cu/Ga atoms, or the common frustration, or both.
Polariton lasing of quasi-whispering gallery modes in a ZnO microwire
Authors: Duan Qingqing , Xu Dan , Liu Wenhui , Lu Jian , Zhang Long , Wang Jian , Wang Yinglei , Gu Jie , Hu Tao , Xie Wei , Shen Xuechu , Chen Zhanghai
Published: July 2013

We report the experimental observation of the quasi-whispering-gallery mode (quasi-WGM) polariton lasing in a one dimensional ZnO microrod cavity at room temperature. Under nonresonant optical pulsed excitation, we measure the pumping power dependence of the emission intensity and the blueshift of the polariton modes, and a fairly low lasing threshold for the quasi-WG mode is determined. We also measure the lasing threshold versus the photon-exciton detuning by dispersion simulations. These experiment results show that both of the WGMs with higher Q factors and the quasi-WGMs with lower Q factors can lase when the detuning between the optical modes and the exciton energies is optimum.
The Effect of Different Feeding Protocols on Compensatory Growth of Black Sea Trout Salmo trutta labrax
Authors: Kocabaş Mehmet , Başçınar Nadir , Kayım Murathan , Er Halil , Şahin Halit
Published: July 2013

The objective of this study was to determine the effects of different feeding protocols on compensatory growth, feeding rate, and feed conversion efficiency of Black Sea Trout Salmo trutta labrax. To our knowledge, no previous feeding experiments with Black Sea Trout have incorporated a fasting period to simulate the handling and acclimation conditions experienced by farmed fish. Fifteen fish per tank (10.69 ± 0.06 cm and 13.22 ± 0.14 g, mean ± SE) were stocked into 40-L fiberglass tanks. Fish were fed with different fasting–feeding regimes for 95 d and were equally allotted to four treatments (Tcont: control; T5–10: 5 d fasting, 10 days feeding; T10–10: 10 d fasting, 10 d feeding; and T15–10: 15 d fasting, 10 d feeding) with three replicates per treatment. The results indicated that length (P = 0.0005), weight (P = 0.000), condition factor (P = 0.013), and specific growth rate (P = 0.014) were significantly affected by the interaction between feeding and time. All fasting treatments showed partial compensation during refeeding. There was an increase in daily feeding rate and feed conversion efficiency in fasting treatments compared with the control treatment. In contrast, at the end of the experiment specific growth rate, condition factor, and body weight in fasting treatments were significantly lower compared with the control treatment. We concluded that there was partial compensation of growth with regular refeeding after periods of feed deprivation (e.g., 5, 10, or 15 d) over a long term and a shorter fasting period may be preferred in order to achieve compensatory growth.
Agreeing to Disagree: Deaf and Hearing Children's Awareness of Subject–Verb Number Agreement
Authors: Breadmore Helen L. , Krott Andrea , Olson Andrew C.
Published: July 2013

This study investigated deaf adolescents' implicit and explicit awareness of subject–verb number agreement. In Experiment 1, a self-paced reading task, the reading times of deaf and hearing children (matched for reading and chronological age, mean = 8;3 and 13;10 years) increased when sentences contained disagreeing subject–verb number markers. However, deaf adolescents' slowing occurred later in the sentence than it did in both groups of hearing children. The same deaf adolescents were unable to detect and correct subject–verb agreement errors in Experiment 2, whereas both groups of hearing children performed well on this task. Thus, deaf adolescents demonstrated implicit awareness of agreement in the absence of explicit knowledge. Moreover, this nascent awareness was below that expected on the basis of their (substantially delayed) reading ability. Therefore, grammatical difficulties could be a significant impediment to deaf children's literacy. Future research should examine whether this is a result of late or incomplete learning of English, bilingualism, or another factor.
Mitotic phosphorylation of Exo84 disrupts exocyst assembly and arrests cell growth
Authors: Luo Guangzuo , Zhang Jian , Luca Francis C. , Guo Wei
Published: July 2013

The rate of eukaryotic cell growth is tightly controlled for proper progression through each cell cycle stage and is important for cell size homeostasis. It was previously shown that cell growth is inhibited during mitosis when cells are preparing for division. However, the mechanism for growth arrest at this stage is unknown. Here we demonstrate that exocytosis of a select group of cargoes was inhibited before the metaphase–anaphase transition in the budding yeast Saccharomyces cerevisiae. The cyclin-dependent kinase, Cdk1, when bound to the mitotic cyclin Clb2, directly phosphorylated Exo84, a component of the exocyst complex essential for exocytosis. Mitotic phosphorylation of Exo84 disrupted the assembly of the exocyst complex, thereby affecting exocytosis and cell surface expansion. Our study demonstrates the coordination between membrane trafficking and cell cycle progression and provides a molecular mechanism by which cell growth is controlled during the cell division cycle.
Direct imaging reveals stable, micrometer-scale lipid domains that segregate proteins in live cells
Authors: Toulmay Alexandre , Prinz William A.
Published: July 2013

It has been proposed that membrane rafts, which are sterol- and sphingolipid-enriched liquid-ordered (Lo) domains, segregate proteins in membranes and play critical roles in numerous processes in cells. However, rafts remain controversial because they are difficult to observe in cells without invasive methods and seem to be very small (nanoscale) and short lived, leading many to question whether they exist or are physiologically relevant. In this paper, we show that micrometer-scale, stable lipid domains formed in the yeast vacuole membrane in response to nutrient deprivation, changes in the pH of the growth medium, and other stresses. All vacuolar membrane proteins tested segregated to one of two domains. These domains formed quasi-symmetrical patterns strikingly similar to those found in liposomes containing coexisting Lo and liquid-disordered regions. Indeed, we found that one of these domains is probably sterol enriched and Lo. Domain formation was shown to be regulated by the pH-responsive Rim101 signaling pathway and may also require vesicular trafficking to vacuoles.
Local palmitoylation cycles define activity-regulated postsynaptic subdomains
Authors: Fukata Yuko , Dimitrov Ariane , Boncompain Gaelle , Vielemeyer Ole , Perez Franck , Fukata Masaki
Published: July 2013

Distinct PSD-95 clusters are primary landmarks of postsynaptic densities (PSDs), which are specialized membrane regions for synapses. However, the mechanism that defines the locations of PSD-95 clusters and whether or how they are reorganized inside individual dendritic spines remains controversial. Because palmitoylation regulates PSD-95 membrane targeting, we combined a conformation-specific recombinant antibody against palmitoylated PSD-95 with live-cell super-resolution imaging and discovered subsynaptic nanodomains composed of palmitoylated PSD-95 that serve as elementary units of the PSD. PSD-95 in nanodomains underwent continuous de/repalmitoylation cycles driven by local palmitoylating activity, ensuring the maintenance of compartmentalized PSD-95 clusters within individual spines. Plasma membrane targeting of DHHC2 palmitoyltransferase rapidly recruited PSD-95 to the plasma membrane and proved essential for postsynaptic nanodomain formation. Furthermore, changes in synaptic activity rapidly reorganized PSD-95 nano-architecture through plasma membrane–inserted DHHC2. Thus, the first genetically encoded antibody sensitive to palmitoylation reveals an instructive role of local palmitoylation machinery in creating activity-responsive PSD-95 nanodomains, contributing to the PSD (re)organization.
Big steps toward understanding dynein
Authors: Kikkawa Masahide
Published: July 2013

Dynein is a microtubule-based molecular motor that is involved in various biological functions, such as axonal transport, mitosis, and cilia/flagella movement. Although dynein was discovered 50 years ago, the progress of dynein research has been slow due to its large size and flexible structure. Recent progress in understanding the force-generating mechanism of dynein using x-ray crystallography, cryo-electron microscopy, and single molecule studies has provided key insight into the structure and mechanism of action of this complex motor protein.
A lifeline for lipid rafts?
Authors: Leslie Mitch
Published: July 2013

Study finds raft-like domains in yeast vacuole membrane.
Didier Stainier: How function follows form
Authors: Sedwick Caitlin
Published: July 2013

Stainier uses zebrafish as a model to study the cellular basis of organ development.
tRNA Nuclear Export inSaccharomyces cerevisiae: In Situ Hybridization Analysis
Authors: Sarkar Srimonti , Hopper Anita K.
Published: July 2013

To understand the factors specifically affecting tRNA nuclear export, we adapted in situ hybridization procedures to locate endogenous levels of individual tRNA families in wild-type and mutant yeast cells. Our studies of tRNAs encoded by genes lacking introns show that nucleoporin Nup116p affects both poly(A) RNA and tRNA export, whereas Nup159p affects only poly(A) RNA export. Los1p is similar to exportin-t, which facilitates vertebrate tRNA export. Alos1 deletion mutation affects tRNA but not poly(A) RNA export. The data support the notion that Los1p and exportin-t are functional homologues. Because LOS1 is nonessential, tRNA export in vertebrate and yeast cells likely involves factors in addition to exportin-t. Mutation of RNA1, which encodes RanGAP, causes nuclear accumulation of tRNAs and poly(A) RNA. Many yeast mutants, including those with the rna1-1mutation, affect both pre-tRNA splicing and RNA export. Our studies of the location of intron-containing pre-tRNAs in therna1-1 mutant rule out the possibility that this results from tRNA export occurring before splicing. Our results also argue against inappropriate subnuclear compartmentalization causing defects in pre-tRNA splicing. Rather, the data support “feedback” of nucleus/cytosol exchange to the pre-tRNA splicing machinery.
Opposite Effects of Insulin on Focal Adhesion Proteins in 3T3-L1 Adipocytes and in Cells Overexpressing the Insulin Receptor
Authors: Wang Qinghua , Bilan Philip J. , Klip Amira
Published: July 2013

Insulin can regulate the abundance and organization of filamentous actin within cells in culture. Early studies using cell lines that overexpress the insulin receptor demonstrated that insulin caused a rapid reversible disassembly of actin filaments that coincided with the rapid tyrosine dephosphorylation of focal adhesion kinase. We have extended these studies by demonstrating that paxillin, another focal adhesion protein, and Src undergo tyrosine dephosphorylation in response to insulin in Chinese hamster ovary (CHO) and rat hepatoma (HTC) cells that overexpress the insulin receptor. This contrasted with the effect of insulin in parental CHO and HTC cells in which focal adhesion proteins were not dephosphorylated in response to the hormone. In addition, insulin caused a dispersion of focal adhesion proteins and disruption of actin filament bundles only in cells that overexpressed the insulin receptor. Moreover, in 3T3-L1 adipocytes, which are considered prototypic insulin-responsive cells, actin filament assembly was stimulated, and focal adhesion protein tyrosine phosphorylation was not altered. 3T3-L1 cells have more insulin receptors than either parental CHO or HTC cells but have fivefold less insulin receptors than the overexpressing cell lines. We hypothesize that a threshold may exist in which the overexpression of insulin receptors determines how insulin signaling pathways regulate the actin cytoskeleton.
An Intronic Enhancer Is Required for Deflagellation-induced Transcriptional Regulation of aChlamydomonas reinhardtiiDynein Gene
Authors: Kang Yong , Mitchell David R.
Published: July 2013

Chlamydomonas reinhardtii flagellar regeneration is accompanied by rapid induction of genes encoding a large set of flagellar structural components and provides a model system to study coordinate gene regulation and organelle assembly. After deflagellation, the abundance of a 70-kDa flagellar dynein intermediate chain (IC70, encoded by ODA6) mRNA increases approximately fourfold within 40 min and returns to predeflagellation levels by ∼90 min. We show by nuclear run-on that this increase results, in part, from increased rates of transcription. To localize cis induction elements, we created an IC70 minigene and measured accumulation, in C. reinhardtii, of transcripts from the endogenous gene and from introduced promoter deletion constructs. Clones containing 416 base pairs (bp) of 5′- and 2 kilobases (kb) of 3′-flanking region retained all sequences necessary for a normal pattern of mRNA abundance change after deflagellation. Extensive 5′- and 3′- flanking region deletions, which removed multiple copies of a proposed deflagellation-response element (the tub box), did not eliminate induction, and the IC70 5′-flanking region alone did not confer deflagellation responsiveness to a promoterless arylsulfatase (ARS) gene. Instead, an intron in the IC70 gene 5′-untranslated region was found to contain the deflagellation response element. These results suggest that the tub box does not play an essential role in deflagellation-induced transcriptional regulation of this dynein gene.
Direct Involvement of N-Cadherin–mediated Signaling in Muscle Differentiation
Authors: Goichberg Polina , Geiger Benjamin
Published: July 2013

Cell–cell interactions, mediated by members of the cadherin family of Ca2+-dependent adhesion molecules, play key roles in morphogenetic processes as well as in the transduction of long-range growth and differentiation signals. In muscle differentiation cell adhesion is involved in both early stages of myogenic induction and in later stages of myoblast interaction and fusion. In this study we have explored the involvement of a specific cadherin, namely N-cadherin, in myogenic differentiation. For that purpose we have treated different established lines of cultured myoblasts with beads coated with N-cadherin–specific ligands, including a recombinant N-cadherin extracellular domain, and anti-N-cadherin antibodies. Immunofluorescent labeling for cadherins and catenins indicated that treatment with the cadherin-reactive beads for several hours enhances the assembly of cell–cell adherens-type junctions. Moreover, immunofluorescence and immunoblotting analyses indicated that treatment with the beads for 12–24 h induces myogenin expression and growth arrest, which are largely independent of cell plating density. Upon longer incubation with the beads (2–3 d) a major facilitation in the expression of several muscle-specific sarcomeric proteins and in cell fusion into myotubes was observed. These results suggest that surface clustering or immobilization of N-cadherin can directly trigger signaling events, which promote the activation of a myogenic differentiation program.