bluuebunny/crossref_metadata_2025 huggingface dataset:
Toughening of poly(lactide) using polyethylene glycol methyl ether acrylate: Reactive versus physical blending
Authors: Kfoury Georgio , Raquez Jean‐Marie , Hassouna Fatima , Leclère Philippe , Toniazzo Valérie , Ruch David , Dubois Philippe
Published: April 2015

To design high‐performance poly(lactide)‐based materials (PLA‐based) with improved toughness, two approaches based on the reactive extrusion (REx) process are investigated and compared in the present study. The first approach relies upon a two‐step procedure using a REx‐polymerized poly(ethylene glycol) methyl ether acrylate, i.e., poly(AcrylPEG), as a highly‐branched and compatible impact modifier for PLA. The free‐radical polymerization proves to be very efficient with a peroxide initiator concentration of 1 wt%. The as‐produced poly(AcrylPEG) is then melt‐blended with PLA by extrusion. The resulting materials exhibit largely increase impact resistance (ca. 35 kJ/m2) in presence of 20 wt% poly(AcrylPEG) in comparison with neat PLA (2.7 kJ/m2), while moderate ductility (tensile elongation at break <40%) and limited plasticization effect are observed. The second “one‐step” approach consists in in situ grafting of AcrylPEG onto PLA backbone via a one‐stage REx. The resulting materials exhibit substantially improved impact resistance (ca. 102 kJ/m2) for AcrylPEG loading of 20 wt%, high ductility (tensile elongation at break of ca. 150%) and efficient plasticization. A detailed characterization of the morphology of the materials has been performed using PF‐QNM‐AFM to better elucidate the structure‐property relationships. POLYM. ENG. SCI., 55:1408–1419, 2015. © 2015 Society of Plastics Engineers
Computational study on reaction enthalpies of urethane‐forming reactions
Authors: Zhao Yusheng , Suppes Galen J.
Published: April 2015

Computational calculations were performed on urethane‐forming reactions using Gaussian 09 software (i.e. molecular modeling) toward the goal of providing thermodynamic parameters. Total electronic and thermal enthalpies and zero‐point vibrational energies of reactants and products were computed by the software and then reaction enthalpies were calculated based on these results. The location of functional groups has the most significant impact on reaction enthalpies while molecular size, chain length and solvent effect have relatively less impact on reaction enthalpies. By comparison to new experimental studies and values reported in literature, better‐informed recommendations on which values of reaction enthalpies to use for urethane foam process simulation were provided. The utility of computational chemistry results succeeded in being an enabling technology to improve foam process simulation. In turn, simulation of urethane‐forming reactions is useful to bridge the gap between fundamental computational chemistry calculations and practical applications. POLYM. ENG. SCI., 55:1420–1428, 2015. © 2015 Society of Plastics Engineers
Nonlinear positive/negative thermal expansion and equations of state of a chain with longitudinal and transverse vibrations
Authors: Kuzkin Vitaly A. , Krivtsov Anton M.
Published: April 2015

Thermal expansion of a classical chain with pair interactions performing longitudinal and transverse vibrations is investigated. Corresponding equations of state are derived analytically using series expansions of pressure and thermal energy with respect to deformations of the bonds caused by thermal motion. In the first approximation the equation of state has Mie–Grüneisen form. The dependence of Grüneisen parameter on deformation of the chain is obtained. For Lennard‐Jones‐like potential Grüneisen parameter varies with deformation from minus infinity (at zero stretching) to plus infinity (at the breakage point). Necessary and sufficient condition for negative thermal expansion at low thermal energies is formulated. Using this condition the potential giving rise to negative thermal expansion in the given range of deformations can be designed. It is shown that at small deformations and finite thermal energies Mie–Grüneisen equation of state strongly overestimates the absolute value of pressure. More accurate nonlinear equation of state is derived for this case. The equation implies that thermal pressure in the unstretched chain is proportional to square root of thermal energy. In the vicinity of the deformation, corresponding to zero Grüneisen parameter, the chain demonstrates negative thermal expansion at low temperatures and positive thermal expansion at higher temperatures. This phenomenon is qualitatively described by the nonlinear equation of state derived in the present paper. The theoretical findings are supported by the results of molecular dynamics simulations.
Concise Review: Targeting Cancer Stem Cells Using Immunologic Approaches
Authors: Pan Qin , Li Qiao , Liu Shuang , Ning Ning , Zhang Xiaolian , Xu Yingxin , Chang Alfred E. , Wicha Max S.
Published: April 2015

Cancer stem cells (CSCs) represent a small subset of tumor cells which have the ability to self-renew and generate the diverse cells that comprise the tumor bulk. They are responsible for local tumor recurrence and distant metastasis. However, they are resistant to conventional radiotherapy and chemotherapy. Novel immunotherapeutic strategies that specifically target CSCs may improve the efficacy of cancer therapy. To immunologically target CSC phenotypes, innate immune responses to CSCs have been reported using Natural killer cells and γδ T cells. To target CSC specifically, in vitro CSC-primed T cells have been successfully generated and shown targeting of CSCs in vivo after adoptive transfer. Recently, CSC-based dendritic cell vaccine has demonstrated significant induction of anti-CSC immunity both in vivo in immunocompetent hosts and in vitro as evident by CSC reactivity of CSC vaccine-primed antibodies and T cells. In addition, identification of specific antigens or genetic alterations in CSCs may provide more specific targets for immunotherapy. ALDH, CD44, CD133, and HER2 have served as markers to isolate CSCs from a number of tumor types in animal models and human tumors. They might serve as useful targets for CSC immunotherapy. Finally, since CSCs are regulated by interactions with the CSC niche, these interactions may serve as additional targets for CSC immunotherapy. Targeting the tumor microenvironment, such as interrupting the immune cell, for example, myeloid-derived suppressor cells, and cytokines, for example, IL-6 and IL-8, as well as the immune checkpoint (PD1/PDL1, etc.) may provide additional novel strategies to enhance the immunological targeting of CSCs. Stem Cells 2015;33:2085–2092
Developing learning progression‐based teacher knowledge measures
Authors: Jin Hui , Shin HyoJeong , Johnson Michele E , Kim JinHo , Anderson Charles W.
Published: April 2015

This study developed learning progression‐based measures of science teachers’ content knowledge (CK) and pedagogical content knowledge (PCK). The measures focus on an important topic in secondary science curriculum using scientific reasoning (i.e., tracing matter, tracing energy, and connecting scales) to explain plants gaining weight and exchanging gases. Using a design‐based research approach, we conducted the research in four cycles. The findings reported in this article were based on the data collected in the last two cycles (year 2011–2012 and year 2012–2013). This study contains two parts. First, 194 teachers participated in professional development workshops and completed a teacher assessment measuring CK and PCK. A learning progression‐based scoring system was developed for these measures. Second, a subgroup of 25 teachers participated in a teaching experiment. These teachers taught a learning progression‐based unit on plant growth and functioning. Their students took written assessments both before and after the teaching intervention. In this process, validity evidence from multiple sources was obtained and analyzed to evaluate the claim that the assessment scores tell how well teachers understand the knowledge essential for teaching the science topic. This validity argument supports our interpretations that led to three results. First, teachers' overall performance on CK was a bit higher than PCK, but not significantly different. Second, two challenges confronting teachers are adaptively applying scientific principles and understanding students' intuitive ideas. Third, there was a statistically significant relationship between teachers' measured CK and PCK and students' learning from the plant unit. © 2015 Wiley Periodicals, Inc. J Res Sci Teach 52: 1269–1295, 2015.
MAPK pathway mediates epithelial‐mesenchymal transition induced by paraquat in alveolar epithelial cells
Authors: Huang Min , Wang Ya‐Peng , Zhu Ling‐Qin , Cai Qian , Li Hong‐Hui , Yang Hui‐Fang
Published: April 2015

Epithelial‐mesenchymal transition (EMT) is believed to be involved in lung fibrosis process induced by paraquat (PQ); however, the molecular mechanism of this process has not been clearly established. The present study investigated the potential involvement of EMT after PQ poisoning. The expressions of EMT markers, such as E‐cadherin and α‐smooth muscle actin (α‐SMA), at multiple time points after exposure to different concentrations of PQ were evaluated by western blot analysis. Following PQ treatment, EMT induction was observed under microscopy. Related fibrosis genes, including Matrix metalloproteinase 2 (MMP‐2), Matrix metalloproteinase 9 (MMP‐9), collagens type I (COL I), and type III (COL III), were also evaluated by measuring their mRNA levels using RT‐PCR analysis. Signaling pathways were analyzed using selective pharmacological inhibitors for MAPK. Cell migration ability was evaluated by scratch wound and Transwell assays. The data showed that PQ‐induced epithelial RLE‐6NT cells to develop mesenchymal cell characteristics, as indicated by a significant decrease in the epithelial marker E‐cadherin and a significant increase in the extracellular matrix (ECM) marker α‐smooth muscle actin in a dose and time‐dependent manner. Moreover, PQ‐treated RLE‐6NT cells had an EMT‐like phenotype with elevated expression of MMP‐2, MMP‐9, and COL I and COL III and enhanced migration ability. Signal pathway analysis revealed that PQ‐induced EMT led to ERK‐1 and Smad2 phosphorylation through activation of the MAPK pathway. The results of the current study indicate that PQ‐induced pulmonary fibrosis occurs via EMT, which is mediated by the MAPK pathway. This implies that the MAPK pathway is a promising therapeutic target in alveolar epithelial cells. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1407–1414, 2016.
Computational analysis of insect impingement patterns on wind turbine blades
Authors: Wilcox Benjamin , White Edward
Published: April 2015

Wind turbines experience significant power loss due to insect contamination on the blades. In order to estimate power losses, computational fluid dynamics software or empirical models are used to compute drag increases due to roughness‐induced boundary‐layer transition. These models require knowledge of the expected levels and location of insect contamination on the blade surface. This is generally unknown, making power loss predictions unreliable. The present study develops a computer simulation to predict this information and uses this tool to simulate insect impingement for a variety of turbine operating conditions. The simulation code combines an invsicid panel method with a Lagrangian insect particle simulation module to first solve for the turbine velocity field and then track insect paths through this field. The effects of blade thickness, angle of attack and insect size are studied for 2D airfoil sections. The simulations show that increasing blade thickness leads to a larger chordwise extent of insect impingement yet lower maximum levels of contamination. Increasing insect mass is also found to increase the chordwise extent of impingement. These results are consistent with previous wind tunnel results and theoretical predictions. The model is then applied to a representative 5‐MW turbine model to determine spanwise variation in contamination. Results agree qualitatively with field observation, suggesting that this technique may be used in the future to more accurately predict power losses on turbines. Copyright © 2015 John Wiley & Sons, Ltd.
Prevention of Genu Recurvatum in Poststroke Patients Using a Hinged Soft Knee Orthosis
Authors: Portnoy Sigal , Frechtel Asaf , Raveh Eitan , Schwartz Isabella
Published: April 2015

Objective

To evaluate the effect of a hinged soft knee orthosis on the gait pattern and symmetry of poststroke patients with chronic symptoms and knee hyperextension.

Design

An 8‐week prospective, randomized, controlled study.

Setting

Outpatient clinic of a Department of Physical Medicine and Rehabilitation in an academic medical center.

Subjects

We recruited adult subjects (N = 31) at a minimum of 3 months after their first stroke. All subjects were able to ambulate independently before their stroke and walked independently with or without a walking aid at the time of recruitment. Subjects also had paresis of leg muscles and/or a spasticity pattern resulting in knee hyperextension.

Interventions

Each subject was tested 3 times, 4 weeks apart. Two tests were performed without the hinged soft knee orthosis, and the third examination was performed with the knee orthosis, after the subject ambulated with it for 4 weeks.

Outcome Measures

Spatiotemporal gait parameters and symmetry and paretic knee angle and muscle activation patterns measured with and without the orthosis. In addition, the Berg Balance Scale, 6‐Minute Walk Test, 10‐Meter Walk Test (10MWT), and Timed Up and Go test were administered.

Results

The orthosis successfully prevented the paretic knee from hyperextending, and greater knee flexion was achieved during the swing phase. The results of the Berg Balance Scale, 6‐Minute Walk Test, 10MWT, and Timed Up and Go Test significantly improved. Although no significant differences were found in spatiotemporal parameters and gait symmetry, 67.7% of the subjects increased their gait velocity by more than 0.1 m/s calculated from the 10MWT, which is considered a clinically meaningful difference on short‐distance walks. The muscle activity patterns did not change while using the orthosis when comparing activation time and peak root mean square values.

Conclusions

Use of a hinged soft knee orthosis to prevent genu recurvatum after stroke may be considered a viable option to alleviate excessive stress from the posterior soft tissues of the paretic knee and to prevent falls by restoring balance and confidence in the patient and by increasing swing knee flexion.
Lonrho in Africa: The Unacceptable Face of Capitalism or the Ugly Face of Neo-Colonialism?
Authors: UCHE CHIBUIKE
Published: April 2015

Under the leadership of Tiny Rowland, Lonrho became the largest and most widely established company in post-independence Africa. Using newly available materials mainly from the National Archives London, this article investigates the activities of Lonrho in Africa and the company’s relationship with the British government during the period. Although Prime Minister Edward Heath publicly labeled the company as the “unacceptable face of capitalism,” evidence presented in this article suggests that this was at best a normative assertion. The subsequent Department of Trade and Industry investigation of Lonrho was carefully guided by the British government with the objective of protecting wider British interests in Africa. Evidence in this article therefore contradicts the view that the British government did not work “in concert” with British businesses in Africa once political independence became imminent.
“A Nation Depends on Its Children”: School Buildings and Citizenship in England and Wales, 1900–1939
Authors: Hulme Tom
Published: April 2015

Calls for a renewed sense of “good citizenship” in the early twentieth century were loud and persistent. Especially important in the citizenship quest was the creation of healthy and efficient children, cured of urban maladies and loyal to a wide notion of community. Such attributes were seen as vital in an economically and militarily competitive world. Historians have already examined the sorts of political and bodily education that arose from these concerns. This article instead looks at how the focus on the body and citizenship was realized in the actual processes of school building. From the medical discourses that underpinned the design of heating, lighting, and ventilation systems, to the emerging focus on the sensory environment of the classroom, the materiality of the school was essential to creating the “good citizen”—physically fit, economically productive, and loyal to the nation.
The “Political Thought” of the “Monarchical Republic of Elizabeth I,” Discovered and Anatomized
Authors: Lake Peter
Published: April 2015

This paper uses two manuscript tracts to reconstruct the vision of the English polity underpinning Lord Burghley's interregnum proposals of 1584–85. These proposals famously prompted Patrick Collinson's work on “the monarchical republic of Elizabeth I,” which in turn became embroiled in subsequent attempts to recuperate distinctively “republican” strands of thought and feeling in sixteenth- and early seventeenth-century England. Written by two clients of central figures in the regime, the two texts are replies to a tract by John Leslie outlining Mary Stuart's claim to the English throne. This tract was republished in 1581 in Latin and then in 1584 in English as part of a Catholic propaganda offensive of the summer of 1584 to which, in turn, the Bond of Association and the interregnum scheme itself were responses. By comparing different versions of the two texts with one another and with Thomas Bilson's later printed tract,The true difference between Christian subjection and unchristian rebellion, something like the structuring assumptions, indeed the political thought, underlying the interregnum scheme can be recovered and analyzed and the republican nature of the monarchical republic assessed in detail for the first time.
Measuring State and District Ideology with Spatial Realignment
Authors: Monogan James E. , Gill Jeff
Published: April 2015

We develop a new approach for modeling public sentiment by micro-level geographic region based on Bayesian hierarchical spatial modeling. Recent production of detailed geospatial political data means that modeling and measurement lag behind available information. The output of the models gives not only nuanced regional differences and relationships between states, but more robust state-level aggregations that update past research on measuring constituency opinion. We rely here on the spatial relationships among observations and units of measurement in order to extract measurements of ideology as geographically narrow as measured covariates. We present an application in which we measure state and district ideology in the United States in 2008.
The Early Medieval Antonine Wall
Authors: Maldonado Adrián
Published: April 2015

Archaeological fieldwork in the Forth-Clyde isthmus has been dominated by the World Heritage Monument of the Antonine Wall, the Roman frontier built in the second centurya.d. Considerably less attention has been given to the evidence for post-Roman experience of the Wall and how it was remembered (and forgotten) in the subsequent centuries. This paper will briefly summarise historical notices of the Antonine Wall, then consider the archaeological and toponymic evidence for early medieval occupation. The role of the Forth-Clyde isthmus as a political frontier is shown to be less significant to our understanding of this period than the evidence for mobility, memory and the contested legacy of Rome in early medieval Scotland.
‘The wide and the narrow gate’: Benchmarking in the SCM Agreement after theCanada–Renewable Energy/FITRuling
Authors: RUBINI LUCA
Published: April 2015

This article discusses the future of benchmarking after theCanada–Renewable Energy/FITcase. This decision left us with bad law. Assuming that any momentous shift, especially in the current regulatory framework that does not provide for any express justification for good subsidies, is difficult, we speculate on what may lie ahead for future litigants and the dispute settlement. Either ‘a wide’ or ‘a narrow road’ can now be followed. After outlining the risks that a normalization and expansion of this ruling may pose (the ‘wide road’), we have responded to the call for clarification and narrowing of this case (the ‘narrow road’) and speculated on how this could be done. The EUAltmarkdecision of the European Court of Justice, which was certainly on the minds of the EU litigators and whose ethos the Appellate Body embraced by referring to the use of ‘price-discovery mechanisms’, has inspired the analysis. The exercise has, however, exposed many challenges and difficulties, many of them having already occurred in EU law. The amount of helpful clarification the WTO judicature could offer is thus limited, and would probably be restricted to taking the link between market definition and benchmarking seriously. This unsatisfactory conclusion leads to suggest, once again, law reform as the only solution to the current status quo.
Why Does the Aurora Flare Up?
Authors: Akasofu Syun-Ichi
Published: April 2015

The spectacular auroras that circle Earth's geomagnetic poles and burst with colorful displays during geomagnetic storms have mystified humanity for millennia. Now scientists are uncovering their secrets.
Investigation of charge transport properties in less defective nanostructured ZnO based Schottky diode
Authors: Dey Arka , Layek Animesh , Roychowdhury Anirban , Das Mrinmay , Datta Joydeep , Middya Somnath , Das Dipankar , Ray Partha Pratim
Published: April 2015

Positron annihilation approved less amount of defect in ZnO: effect on the performance of Al/ZnO/ITO Schottky diode.
Synchronous–asynchronous two-dimensional correlation spectroscopy for the discrimination of adulterated milk
Authors: Yang Renjie , Dong Guimei , Sun Xueshan , Yu Yaping , Liu Haixue , Yang Yanrong , Zhang Weiyu
Published: April 2015

A novel approach for the discriminant analysis of adulterated milk is proposed using synchronous–asynchronous two-dimensional correlation spectroscopy and NPLS-DA.
Atomic structure of defects and interfaces in TiO2-B and Ca:TiO2-B (CaTi5O11) films grown on SrTiO3
Authors: Kim Sung Joo , Zhang Kui , Katz Michael B. , Li Baihai , Graham George W. , Pan Xiaoqing
Published: April 2015

An atomic-scale analysis of the interfacial structure and defects in CaTi5O11grown on SrTiO3and TiO2-B grown on CaTi5O11is presented.
CO oxidation activity of thermally stable Fe–Cu/CeO2 catalysts prepared by dual-mode arc-plasma process
Authors: Hinokuma Satoshi , Yamashita Noriko , Katsuhara Yasuo , Kogami Hayato , Machida Masato
Published: April 2015

Fe–Cu bimetal nanoparticles were prepared by the dual-mode arc-plasma process. The CO oxidation activity of Fe–Cu/CeO2 was enhanced by thermal aging at 900 °C. CO oxidation over aged Fe–Cu/CeO2 proceeded via the Mars–van Krevelen mechanism.
Synthesis of a new type of alkene metal complex using face-capping thione-alkene ligands
Authors: Zhang Long , Yan Tao , Han Ying-Feng , Hahn F. Ekkehardt , Jin Guo-Xin
Published: April 2015

A series of complexes of novel chelating thione-alkene S(η2-CC)S tridentate ligands bound to late transition metals (Ir, Rh, Pd) were isolated and characterised.
Scaling of graphene integrated circuits
Authors: Bianchi Massimiliano , Guerriero Erica , Fiocco Marco , Alberti Ruggero , Polloni Laura , Behnam Ashkan , Carrion Enrique A. , Pop Eric , Sordan Roman
Published: April 2015

The scaling of graphene sub-micron integrated circuits was demonstrated by fabricating and characterizing graphene ring oscillators of different gate lengths, exhibiting the highest oscillation frequency of 4.3 GHz obtained in any strictly low-dimensional material to date.
Highly dispersed molybdenum carbide nanoparticles supported on activated carbon as an efficient catalyst for the hydrodeoxygenation of vanillin
Authors: He Lili , Qin Yu , Lou Hui , Chen Ping
Published: April 2015

Characterized by XRD and TEM, highly dispersed molybdenum carbide (Mo2C) nanoparticles with a diameter of 1–4 nm were effectively synthesized on activated carbon at 700 °C.
Solution-processed SiO2 gate insulator formed at low temperature for zinc oxide thin-film transistors
Authors: Jeong Yesul , Pearson Christopher , Kim Hyun-Gwan , Park Man-Young , Kim Hongdoo , Do Lee-Mi , Petty Michael C.
Published: April 2015

A ZnO transistor with carrier mobility of 3 cm2 V−1 s−1 using a SiO2 insulator formed at low-temperature (180 °C) from solution-processed perhydropolysilazane.
Mesoporous silicas: improving the adsorption efficiency of phenolic compounds by the removal of amino group from functionalized silicas
Authors: Morsli Amine , Benhamou Abdellah , Basly Jean-Philippe , Baudu Michel , Derriche Zoubir
Published: April 2015

Removal of the amine template enhances the sorption of phenolic pollutants. The sorption capacity could be dependent of the pore size.
Tetrabutylammonium tribromide impregnated MCM-48 as a heterogeneous catalyst for selective oxidation of sulfides
Authors: Gogoi Prasanta , Hazarika Sukanya , Barman Pranjit
Published: April 2015

We report here tetrabutylammonium tribromide supported on MCM-48 as a highly efficient heterogeneous catalyst for the selective oxidation of sulfides, in ethanolic medium using hydrogen peroxide as an oxidant.
One-step synthesis of copper compounds on copper foil and their supercapacitive performance
Authors: Xu Panpan , Ye Ke , Du Mengmeng , Liu Jijun , Cheng Kui , Yin Jinling , Wang Guiling , Cao Dianxue
Published: April 2015

Nanowire-like Cu(OH)2arrays, microflower-like CuO standing on Cu(OH)2nanowires and hierarchical CuO microflowers are directly synthesizedviaa simple and cost-effective liquid–solid reaction.
Nonthermal fluctuations of the mitotic spindle
Authors: Smith Kevin , Griffin Brian , Byrd Henry , MacKintosh F. C. , Kilfoil Maria L.
Published: April 2015

Quantitative measurements of fluctuations in the nucleus of mitotic cells can be fully accounted for by a simple model of de-correlated active force fluctuations in a viscoelastic medium dominated by a solution of DNA.
Long lifetime blue phosphorescent organic light-emitting diodes with an exciton blocking layer
Authors: Seo Jeong-A , Jeon Sang Kyu , Gong Myoung Seon , Lee Jun Yeob , Noh Chang Ho , Kim Sung Han
Published: April 2015

An acridine derived compound, 9,9-dimethyl-10-(9-phenyl-9H-carbazol-3-yl)-9,10-dihydroacridine (PCZAC), was newly designed as a hole transport type high triplet energy material for application as a hole transport type exciton blocking layer of blue phosphorescent organic light-emitting diodes.
Computational Modeling for Language Acquisition: A Tutorial With Syntactic Islands
Authors: Pearl Lisa S. , Sprouse Jon
Published: April 2015

Purpose

Given the growing prominence of computational modeling in the acquisition research community, we present a tutorial on how to use computational modeling to investigate learning strategies that underlie the acquisition process. This is useful for understanding both typical and atypical linguistic development.

Method

We provide a general overview of why modeling can be a particularly informative tool and some general considerations when creating a computational acquisition model. We then review a concrete example of a computational acquisition model for complex structural knowledge referred to as
syntactic islands
. This includes an overview of syntactic islands knowledge, a precise definition of the acquisition task being modeled, the modeling results, and how to meaningfully interpret those results in a way that is relevant for questions about knowledge representation and the learning process.

Conclusions

Computational modeling is a powerful tool that can be used to understand linguistic development. The general approach presented here can be used to investigate any acquisition task and any learning strategy, provided both are precisely defined.
Observer‐based controller design with disturbance feedforward framework for formation control of satellites
Authors: Menon Prathyush P. , Edwards Christopher , Gomes Paulino Nuno M.
Published: April 2015

In this study, a bespoke sliding mode non‐linear observer and a linear controller framework is proposed for achieving robust formation control of a cluster of satellites in the case of a circular reference orbit. Exploiting the structure of the satellite dynamics, a non‐linear observer is proposed based on super‐twist sliding mode ideas. The observer estimates the states and any unknown bounded disturbances in ‘finite time’. The stability properties of the observers are demonstrated using Lyapunov techniques. A distributed controller, based on the estimated states and the relative position output information, depending on the underlying communication topology, is proposed. A polytopic representation of the collective dynamics which depends on the eigenvalues of the Laplacian matrix associated with the communication topology is used to synthesise the gains of the proposed control laws. A simulation example is used to demonstrate the efficacy of the proposed approach.
Automatic determination of important mode–mode correlations in many-mode vibrational wave functions
Authors: König Carolin , Christiansen Ove
Published: April 2015

We introduce new automatic procedures for parameterizing vibrational coupled cluster (VCC) and vibrational configuration interaction wave functions. Importance measures for individual mode combinations in the wave function are derived based on upper bounds to Hamiltonian matrix elements and/or the size of perturbative corrections derived in the framework of VCC. With a threshold, this enables an automatic, system-adapted way of choosing which mode–mode correlations are explicitly parameterized in the many-mode wave function. The effect of different importance measures and thresholds is investigated for zero-point energies and infrared spectra for formaldehyde and furan. Furthermore, the direct link between important mode–mode correlations and coordinates is illustrated employing water clusters as examples: Using optimized coordinates, a larger number of mode combinations can be neglected in the correlated many-mode vibrational wave function than with normal coordinates for the same accuracy. Moreover, the fraction of important mode–mode correlations compared to the total number of correlations decreases with system size. This underlines the potential gain in efficiency when using optimized coordinates in combination with a flexible scheme for choosing the mode–mode correlations included in the parameterization of the correlated many-mode vibrational wave function. All in all, it is found that the introduced schemes for parameterizing correlated many-mode vibrational wave functions lead to at least as systematic and accurate calculations as those using more standard and straightforward excitation level definitions. This new way of defining approximate calculations offers potential for future calculations on larger systems.
Time-dependent density functional theory for open systems with a positivity-preserving decomposition scheme for environment spectral functions
Authors: Wang RuLin , Zheng Xiao , Kwok YanHo , Xie Hang , Chen GuanHua , Yam ChiYung
Published: April 2015

Understanding electronic dynamics on material surfaces is fundamentally important for applications including nanoelectronics, inhomogeneous catalysis, and photovoltaics. Practical approaches based on time-dependent density functional theory for open systems have been developed to characterize the dissipative dynamics of electrons in bulk materials. The accuracy and reliability of such approaches depend critically on how the electronic structure and memory effects of surrounding material environment are accounted for. In this work, we develop a novel squared-Lorentzian decomposition scheme, which preserves the positive semi-definiteness of the environment spectral matrix. The resulting electronic dynamics is guaranteed to be both accurate and convergent even in the long-time limit. The long-time stability of electronic dynamics simulation is thus greatly improved within the current decomposition scheme. The validity and usefulness of our new approach are exemplified via two prototypical model systems: quasi-one-dimensional atomic chains and two-dimensional bilayer graphene.
Molecular dynamics simulations of solutions at constant chemical potential
Authors: Perego C. , Salvalaglio M. , Parrinello M.
Published: April 2015

Molecular dynamics studies of chemical processes in solution are of great value in a wide spectrum of applications, which range from nano-technology to pharmaceutical chemistry. However, these calculations are affected by severe finite-size effects, such as the solution being depleted as the chemical process proceeds, which influence the outcome of the simulations. To overcome these limitations, one must allow the system to exchange molecules with a macroscopic reservoir, thus sampling a grand-canonical ensemble. Despite the fact that different remedies have been proposed, this still represents a key challenge in molecular simulations. In the present work, we propose the Constant Chemical Potential Molecular Dynamics (CμMD) method, which introduces an external force that controls the environment of the chemical process of interest. This external force, drawing molecules from a finite reservoir, maintains the chemical potential constant in the region where the process takes place. We have applied the CμMD method to the paradigmatic case of urea crystallization in aqueous solution. As a result, we have been able to study crystal growth dynamics under constant supersaturation conditions and to extract growth rates and free-energy barriers.
Numerical analysis for finite-range multitype stochastic contact financial market dynamic systems
Authors: Yang Ge , Wang Jun , Fang Wen
Published: April 2015

In an attempt to reproduce and study the dynamics of financial markets, a random agent-based financial price model is developed and investigated by the finite-range multitype contact dynamic system, in which the interaction and dispersal of different types of investment attitudes in a stock market are imitated by viruses spreading. With different parameters of birth rates and finite-range, the normalized return series are simulated by Monte Carlo simulation method and numerical studied by power-law distribution analysis and autocorrelation analysis. To better understand the nonlinear dynamics of the return series, a q-order autocorrelation function and a multi-autocorrelation function are also defined in this work. The comparisons of statistical behaviors of return series from the agent-based model and the daily historical market returns of Shanghai Composite Index and Shenzhen Component Index indicate that the proposed model is a reasonable qualitative explanation for the price formation process of stock market systems.
Effects of local electric surface potential on holes charging process in uncapped germanium nanocrystal
Authors: Marchand Aude , El Hdiy Abdelillah
Published: April 2015

The charging kinetics of holes are investigated in an uncapped Ge nanocrystal by the use of the nano-electron beam induced current technique. The charging process is studied under zero volt or under an appropriate electric field. The investigation is repeated many times on the same nanocrystal and on others in the same sample to attest of the reproducibility of the results. At 0 V, the cycles of charging kinetics are superimposed and are in a steady state, but an instantaneous local and negative surface potential, established in the nanocrystal at the beginning of the kinetics, slows down the holes charging process. Under an external field, the energy band bending accentuation affects the holes charging time constants. As a result, the holes charging cycles weakly affect the electrical performance of the thin oxide as is indicated by the value of the measured local resistivity of 6 × 1010–1011 Ω cm, which is relatively lower than that of the thick thermal oxide.
Temporal and spatial instability of a compound jet in a surrounding gas
Authors: Afzaal Muhammad F. , Uddin Jamal , Alsharif Abdullah M. , Mohsin Muhammad
Published: April 2015

Droplet generated from the rupture of a compound liquid jet can be used to produce encapsulated droplets which have applications in a wide variety of industrial processes. In this paper, we examine the instability of a two dimensional axisymmetric inviscid compound jet falling vertically downwards in a surrounding gas under the influence of gravity. The steady state equations are derived using an asymptotic method and the linear instability, including temporal and spatial instability, is determined using a multiple scales approach. The results are analysed to investigate how the gas-to-shell density ratio affects key features of the jet including theoretical breakup lengths.
Magnetic field measurement by weak magnetic-sensitive Zeeman splitting
Authors: Dong Richang , Wei Rong , Du Yuanbo , Zou Fan , Lin Jinda , Wang Yuzhu
Published: April 2015

We present a method for magnetic field measurement by the weak magnetic-sensitive Zeeman splitting based on stimulated Raman transition. The magnetic field intensity measured by our proposed method is consistent with that by the magnetic-sensitive method in the error range of 0.5%. Compared with the traditional measurement, the contrast of the weak magnetic-sensitive resonance signal is improved significantly for gradient field. The dependence of the Raman transitions on polarization schemes is analyzed. The cancellation of the differential light shift between the separated peaks is demonstrated by proper choice of polarization configuration. The presented method is applicable to measuring the magnetic field with large gradient, such as 2–40 mG/mm in our clock, where the traditional method is unsuitable.
Convergent evolution toward an improved growth rate and a reduced resistance range inProchlorococcusstrains resistant to phage
Authors: Avrani Sarit , Lindell Debbie
Published: April 2015

Significance

High abundances of the important primary producing cyanobacterium,Prochlorococcus, and its parasitic phages, inhabit vast expanses of the world’s oceans. Their coexistence is facilitated by genetic diversity that has led to an assortment ofProchlorococcussubpopulations with differences in susceptibility and resistance to co-occurring phages. Here, we investigated the fate of recently emerging phage-resistantProchlorococcusstrains. We found that genetic diversification increases, as these strains evolve toward an improved growth rate and reduced resistance range, leading to phenotypes intermediary between the original susceptible and initial resistant strains. These findings suggest a continual increase in the combinatorial interactions betweenProchlorococcusand its phages and that the oceans are populated with rapidly growingProchlorococcuscells with varying degrees of phage resistance.
National Identity After Communism: Hungary’s Statue Park
Authors: deTar Matthew
Published: April 2015

This article analyzes the development of national identity and political ideology in Hungary’s Szoborpark (Statue Park), where resides a collection of Soviet-era statues relocated from the city streets and public squares of Budapest in 1993. Although a narrative of the Cold War and the theory of postcommunism enable understandings of the park as a decisive break with the past, this article argues that Statue Park constructs a more ambivalent sense of politics, identity, and history in Hungary. By showing that the park represents a number of conflicting and unresolved features of Hungarian national identity and politics, the article helps demonstrate the way that a sweeping historical narrative like the Cold War can produce inaccurate understandings of local political developments in post-Soviet countries.
Capture of the Canary mantle plume material by the Gibraltar arc mantle wedge during slab rollback
Authors: Mériaux C.A. , Duarte J.C. , Duarte S.S. , Schellart W.P. , Chen Z. , Rosas F. , Mata J. , Terrinha P.
Published: April 2015

Recent evidence suggests that a portion of the Canary plume travelled northeastwards below the lithosphere of the Atlas Mountains in North Africa towards the Alboran domain and was captured ∼10 Ma ago by the Gibraltar subduction system in the Western Mediterranean. The capture would have been associated with the mantle return flow induced by the westward-retreating slab that would have dragged and trapped a portion of the plume material in the mantle wedge of the Gibraltar subduction zone. Such material eventually contaminated the subduction related volcanism in the Alboran region. In this work, we use scaled analogue models of slab–plume interaction to investigate the plausibility of the plume capture. An upper-mantle-scaled model combines a narrow (400 km) edge-fixed subduction plate with a laterally offset compositional plume. The subduction dominated by slab rollback and toroidal mantle flow is seen to increasingly impact on the plume dynamics as the area of influence of the toroidal flow cells at the surface is up to 500 × 1350 km2. While the plume head initially spreads axisymmetrically, it starts being distorted parallel to the plate in the direction of the trench as the slab trench approaches the plume edge at a separation distance of about 500 km, before getting dragged towards mantle wedge. When applied to the Canary plume–Gibraltar subduction system, our model supports the observationally based conceptual model that mantle plume material may have been dragged towards the mantle wedge by slab rollback-induced toroidal mantle flow. Using a scaling argument for the spreading of a gravity current within a channel, we also show that more than 1500 km of plume propagation in the sublithospheric Atlas corridor is dynamically plausible.
Middle Platonism
Authors: Bonazzi Mauro
Published: April 2015

The term “Middle Platonism” was created in the 19th century ce to distinguish this movement from the later tradition known as “Neoplatonism.” Both terms, however, are misleading and would have been rejected by the ancients; neither “Middle Platonists” would have accepted that they were an intermediate step in the history of Platonism nor would “Neoplatonists” have agreed that they were introducing anything new in the Platonic tradition. However, it is true that Early Imperial Platonism differs in basic ways from Late Antique Platonism, and both labels continue to be used for the sake of clarity. In short, Middle Platonism conventionally refers to a group of philosophers from the 1st century bce to the 3rd century ce who may be described as Platonists by virtue of their allegiance to a nucleus of Platonic doctrines. More precisely, this allegiance can be presented as the attempt to develop a systematic and theological interpretation of Plato’s philosophy. This suffices to prove its importance, philosophically and historically, for two reasons: (1) because the commitment to the view that Plato’s philosophy can be reduced to a system proved very influential in the history of philosophy, and (2) because in this period monotheistic religions such as Judaism and Christianity first encountered Greek philosophy, and this confrontation was greatly influenced by the theological speculations of these authors. Unfortunately, most of the works of Middle Platonists are now lost, but the material that remains enable us to reconstruct the basic features of their thought.
Germany in World War II
Authors: Panayi Panikos
Published: April 2015

In Germany, World War II does not usually form a distinct and compact period, as it does in other states, such as Great Britain, the United States, or Russia. The most recognized phases in the history of 20th-century Germany are the Kaiserreich (1890–1919), the Weimar Republic (1919–1933), the Third Reich (1933–1945), divided Germany (1945–1989), and reunified Germany (after 1989). World War II usually receives attention as part of the history of the Third Reich. On the other hand, historians of the war often approach the conflict from a German-centered perspective. Some differences exist between German and Anglo-American historians, with the former, especially those who work on local history, more likely to examine World War II as a distinct period, although some recent major works have begun to buck this trend in Anglo-American scholarship. In recent years, the multivolume Clarendon history Germany and the Second World War, translated from the German Das Deutsche Reich und der Zweite Weltkrieg, has helped to unify the Anglo-American and German perspectives. Some of the publications included in this article, however, view the war in Germany as part of the wider history of the Third Reich. From the outset, Nazi Germany, and World War II within it, has given rise to a vast literature, which began as the Nazis rose to power and has continued unabated until the present. This article can therefore only provide the briefest of introductions to this enormous historiography by outlining the key publications in these areas: General Overviews; Push to War; Invasion of Eastern Europe; Bombing of German Cities; Economic Mobilization; Genocide; Foreign Workers and Prisoners of War; Local History; Women; Children; Repression and Resistance; Religion; Propaganda; and Defeat.
Teaching Chest Ultrasound in an Experimental Porcine Model
Authors: Sanchez-de-Toledo Joan , Renter-Valdovinos Luis , Esteves Marielle , Fonseca Carla , Villaverde Ivan , Rosal Marta
Published: April 2015

Objective

The objective of this study was to evaluate the efficacy of a short hands-on chest ultrasound course to detect normal lung pattern, pneumothorax (PTX), and pleural effusion (PE) in a porcine animal model.

Methods

Thirty-six trainees with no previous experience in chest ultrasound participated in the study. A 1.5-hour training course covering both theory and practice was developed. All static and dynamic signs of the normal lung parenchyma, PTX, and PE were analyzed. Four pigs were used. Approval by the local institutional animal care was obtained. An 8F drainage catheter was inserted into the pleural cavity under general anesthesia for injection of air or saline solution. A Vivid Q ultrasound with a 12L-RS linear probe was used. A baseline preintervention evaluation and 2 postintervention evaluations (one after theoretical class and the other after additional training with the animal model) were made. Sensitivity and specificity with the 95% confidence interval for recognition of the 3 patterns were analyzed, and results were compared with those obtained in the preintervention evaluation.

Results

All normal lung signs were detected, as these were signs of PE and PTX. Participants were able to diagnose a normal pattern (sensitivity, 100% [90%–100%]; specificity, 90% [84%–95%]), PE (sensitivity, 89% [75%–95%]; specificity, 95% [89%–98%]), and PTX (sensitivity, 82% [72%–89%]; specificity, 97% [90%–99%]) after 30 minutes of class and normal pattern (sensitivity, 95% [85%–98%]; specificity, 95% [85%–98%]), PE (sensitivity, 100% [88%–100%]; specificity, 98% [94%–99%]), and PTX (sensitivity, 90% [73%–96%]; specificity, 98% [92%–99%]) in the animal model.

Conclusions

The porcine model is useful for ultrasound examination of the lung parenchyma and detection of pleural disease. Its use in the experimental laboratory is a major refinement that enables trainees to identify acute pulmonary complications.