bluuebunny/crossref_metadata_2025 huggingface dataset:
A solution to the motion planning and control problem of a car-like robot via a single-layer perceptron
Authors: Prasad Avinesh , Sharma Bibhya , Vanualailai Jito
Published: December 2013

This paper tackles the problem of motion planning and control of a car-like robot in an obstacle-ridden workspace. A kinematic model of the vehicle, governed by a homogeneous system of first-order differential equations, is used. A solution to the multi-tasking problem of target convergence, obstacle avoidance, and posture control is then proposed. The approach of solving the problem is two-fold. Firstly, a novel velocity algorithm is proposed to drive the car-like robot from its initial position to the target position. Secondly, a single layer artificial neural network is trained to avoid disc-shaped obstacles and provide corresponding weights, which are then used to develop a function for the steering angles. Thus, our method does not need a priori knowledge of the environment except for the goal position. With the help of the Direct Method of Lyapunov, it is shown that the proposed forms of the velocity and steering angle ensure point stability. For posture stability, we model the two parallel boundaries of a row-structured parking bay as continua of disk-shaped obstacles. Thus, our method is extendable to ensuring posture stability, which gives the desired final orientation. Computer simulations of the generated path are presented to illustrate the effectiveness of the method.
Some geometric, kinematic, and dynamic considerations on Stewart-Gough platforms with singularity analysis
Authors: Sarıgül A. Saide , Güneri Burcu
Published: December 2013

In this study, some geometric, kinematic, and dynamic aspects of the design of a Stewart-Gough platform are examined. The focus of the analyses is on a particular Stewart-Gough platform that we have constructed. The analysis begins with workspace simulations for different moving platform orientations. The computations extend to a parametric study of some geometric and kinematic constraints: Joint angle, rotation angle, and limb length. Actuator force is another parameter considered; and the triple relationship between workspace, joint angle, and actuator force is discussed. Parametric analyses are culminated with a brief discussion of the real design parameters.
Optimal motion planning of juggling by 3-DOF manipulators using adaptive PSO algorithm
Authors: Akbarimajd Adel
Published: December 2013

Three-DOF manipulators were employed for juggling of polygonal objects in order to have full control over object's configuration. Dynamic grasp condition is obtained for the instances that the manipulators carry the object on their palms. Manipulation problem is modeled as a nonlinear optimal control problem. In this optimal control problem, time of free flight is used as a free parameter to determine throw and catch times. Cost function is selected to get maximum covered horizontal distance using minimum energy. By selecting third-order polynomials for joint motions, the problem is changed to a constrained parameter selection problem. Adaptive particle swarm optimization method is consequently employed to solve the optimization problem. Effectiveness of the optimization algorithm is verified by a set of simulations in MSC. ADAMS.
Reciprocal transplant experiment suggests host specificity of the mistletoe Agelanthus natalitius in South Africa
Authors: Okubamichael Desale Y. , Griffiths Megan E. , Ward David
Published: December 2013

We surveyed the community composition of trees that host the mistletoe Agelanthus natalitius (Loranthaceae) at two sites (Highover and Mtontwane) in South Africa. We recorded a total of 1464 trees (Acacia karroo and A. caffra) hosting 1202 mistletoes in the 64 surveyed plots (20 × 50 m). There were almost four times as many A. karroo as A. caffra at Highover and three times as many A. karroo as A. caffra at Mtontwane. There was no significant difference in prevalence (percentage of infected trees) at Highover (A. karroo = 22% and A. caffra = 26%), but a significantly greater percentage of A. caffra trees were parasitized at Mtontwane (A. karroo = 25% and A. caffra = 34%). Intensity of infection (number of mistletoe infections per tree) was higher for A. karroo (0.73 ± 0.04 and 1.03 ± 0.64) than for A. caffra (0.66 ± 0.01 and 0.89 ± 0.035) at Highover and Mtontwane, respectively. Prevalence and intensity of infection showed a significant positive relationship with tree size for both host species at both sites. We tested the genotype-by-environment interaction effects in this mistletoe by conducting reciprocal transplant experiments (64 individual trees each received 20 seeds). Initial germination was not site-, substrate- or host-sensitive. However, a general pattern was found that hypocotyls of the germinated seeds grew longer when seeds were placed on the same host species as the parent plant within their own source locality. Consistent with this observation, mistletoes placed on their source host species generally had higher survival than those transferred to non-source host species after 6 mo. Overall, mistletoe seeds from parent plants on A. karroo and mistletoe seeds placed on A. karroo had the highest survival. This could be the result of an adaptation of the mistletoe to the most frequently encountered host species.
THE OPTIMAL ADMISSION THRESHOLD IN OBSERVABLE QUEUES WITH STATE DEPENDENT PRICING
Authors: Borgs Christian , Chayes Jennifer T. , Doroudi Sherwin , Harchol-Balter Mor , Xu Kuang
Published: December 2013

We consider the social welfare model of Naor [20] and revenue-maximization model of Chen and Frank [7], where a single class of delay-sensitive customers seek service from a server with an observable queue, under state dependent pricing. It is known that in this setting both revenue and social welfare can be maximized by a threshold policy, whereby customers are barred from entry once the queue length reaches a certain threshold. However, no explicit expression for this threshold has been found. This paper presents the first derivation of the optimal threshold in closed form, and a surprisingly simple formula for the (maximum) revenue under this optimal threshold. Utilizing properties of the Lambert W function, we also provide explicit scaling results of the optimal threshold as the customer valuation grows. Finally, we present a generalization of our results, allowing for settings with multiple servers.
Quantifying the risk of respiratory infection in healthcare workers performing high-risk procedures
Authors: MACINTYRE C. R. , SEALE H. , YANG P. , ZHANG Y. , SHI W. , ALMATROUDI A. , MOA A. , WANG X. , LI X. , PANG X. , WANG Q.
Published: December 2013

This study determined the risk of respiratory infection associated with high-risk procedures (HRPs) performed by healthcare workers (HCWs) in high-risk settings. We prospectively studied 481 hospital HCWs in China, documented risk factors for infection, including performing HRPs, measured new infections, and analysed whether HRPs predicted infection. Infection outcomes were clinical respiratory infection (CRI), laboratory-confirmed viral or bacterial infection, and an influenza infection. About 12% (56/481) of the study participants performed at least one HRP, the most common being airway suctioning (7·7%, 37/481). HCWs who performed a HRP were at significantly higher risk of developing CRI and laboratory-confirmed infection [adjusted relative risk 2·9, 95% confidence interval (CI) 1·42–5·87 and 2·9, 95% CI 1·37–6·22, respectively]. Performing a HRP resulted in a threefold increase in the risk of respiratory infections. This is the first time the risk has been prospectively quantified in HCWs, providing data to inform occupational health and safety policies.
Serological survey of a new type of reovirus in humans in China
Authors: BAI B. , SHEN H. , HU Y. , HOU J. , LIU Z. , LI R. , CHAI Y. , HUANG W. , MAO P.
Published: December 2013

To evaluate the presence of a new type of reovirus (designated R4) in humans, we determined the prevalence of specific antibodies using a neutralization assay and ELISA. The sera from 97 healthy people and 219 patients in our hospital with measles, hand-foot-and-mouth disease, liver diseases, and diarrhoea were investigated. Although the study population was limited, our data suggested that R4 is widespread in the human population. A significantly higher level of R4-specific antibody in patients than in healthy people is worthy of consideration, since it poses a risk for aggravation of the extant illness by the reovirus.
Population dynamics ofStaphylococcus aureusfrom Northeastern Nigeria in 2007 and 2012
Authors: OKON K. O. , SHITTU A. O. , KUDI A. A. , UMAR H. , BECKER K. , SCHAUMBURG F.
Published: December 2013

The population structure ofStaphylococcus aureusis changing globally but the situation regarding dominant clones in sub-Saharan Africa is not clear. We therefore assessed changes in the population structure of clinicalS. aureusisolates obtained in 2007 (n = 75) and 2012 (n = 75) from Northeastern Nigeria. A reduction in resistance to penicillin, gentamicin, erythromycin and clindamycin was observed in 2012. A decrease of methicillin resistance rates (13·3% to 8·0%) was associated with the decline of the ST241 MRSA clone. The proportion of Panton–Valentine leukocidin (PVL)-positive isolates also decreased from 65·3% to 44%, and was linked with the emergence of PVL-negative ST601 clone in 2012. The significant decline in antibiotic resistance in the study area is in contrast to the worldwide trend of increasing resistance rates.
Seasonality of reported tuberculosis cases from 2006 to 2010 in Wuhan, China
Authors: LUO T. , SUMI A. , ZHOU D. , KOBAYASHI N. , MISE K. , YU B. , KONG D. , WANG J. , DUAN Q.
Published: December 2013

We investigated the seasonality of tuberculosis (TB) in Wuhan, China, to evaluate the increased risk of disease transmission during each season and to develop an effective TB control strategy. We applied spectral analysis to the weekly prevalence data of sputum smear positive (SSP) and sputum smear negative (SSN) pulmonary TB reported from 2006 to 2010. Cases of both SSP and SSN feature 1·0- and 0·5-year periodic modes. The least squares method was used to fit curves to the two periodic modes for SSP and SSN data. The curves demonstrated dominant peaks in spring similar to cases reported previously for other locations. Notably for SSP, dominant peaks were also observed in summer. The spring peaks of SSP and SSN were explained in terms of poorly ventilated and humid rooms and vitamin D deficiency. For the summer peaks of SSP, summer influenza epidemics in Wuhan may contribute to the increase in TB prevalence.
Enterobius vermicularis and allergic conditions in Norwegian children
Authors: BØÅS H. , TAPIA G. , RASMUSSEN T. , RØNNINGEN K. S.
Published: December 2013

Studies investigating the association between Enterobius vermicularis and allergic conditions have shown conflicting results. This study was conducted to test for any such associations in Norwegian children. Parents were asked to answer questionnaires concerning their children's history of allergies, wheezing or eczema and pinworm infections. Current pinworm infections were diagnosed by microscopic examination of anal scotch tape samples. The data were analysed using logistic regression. Atopic eczema, allergy or wheezing was reported to be confirmed by a physician in 23% of the children (84/364). A possible association between current pinworm infections and food allergy was found, with 17·5% of children without food allergy testing positive for pinworms, compared to 36·8% of children with food allergy (odds ratio 2·9, 95% confidence interval 1·1–8·0). No association was found between past pinworm treatments and present atopic conditions. The association between current E. vermicularis infections and food allergy warrants further study.
The Clergy Discipline Measure 2003: A Progress Report
Authors: Iles Adrian
Published: December 2013

The Clergy Discipline Measure has been in force since 1 January 2006. The Measure provides a structure for dealing with formal complaints of misconduct against members of the clergy except in relation to matters involving doctrine, ritual or ceremonial, which continue to be governed by the Ecclesiastical Jurisdiction Measure 1963. This article looks at how the Measure has worked in practice, and considers amendments to the Measure that have recently been made.
The Faculty Jurisdiction Rules 2013: Simpler Process, Equal Protection
Authors: Hill Mark
Published: December 2013

The faculty jurisdiction of the Church of England pre-dates planning law by several centuries. It is the means by which the diocesan bishop, through his chancellor and in his consistory court, ensures that the sacred buildings of the diocese and their contents are compliant with the canon law, doctrine and ecclesiology of the Church of England. During the latter part of the last century, the effective operation of the faculty jurisdiction contributed to the continuing exclusion of churches of the Church of England from the need for listed building control. The rationale is that the faculty jurisdiction provides a level of protection for the church's built heritage equivalent to local authority protection, but uniquely tailored for the sacred purpose of the buildings and the evolving needs of individual worshipping communities. A balance constantly needs to be struck which respects the rigour required of both ecclesiastical and secular authorities (with their competing but complementary demands), but is not so cumbersome that it deters and frustrates parishes and other interested persons and bodies from engaging with it.
Contextual equivalence for inductive definitions with binders in higher order typed functional programming
Authors: LAKIN MATTHEW R. , PITTS ANDREW M.
Published: December 2013

Correct handling of names and binders is an important issue in meta-programming. This paper presents an embedding of constraint logic programming into the αML functional programming language, which provides a provably correct means of implementing proof search computations over inductive definitions involving names and binders modulo α-equivalence. We show that the execution of proof search in the αML operational semantics is sound and complete with regard to the model-theoretic semantics of formulae, and develop a theory of contextual equivalence for the subclass of αML expressions which correspond to inductive definitions and formulae. In particular, we prove that αML expressions, which denote inductive definitions, are contextually equivalent precisely when those inductive definitions have the same model-theoretic semantics. This paper is a revised and extended version of the conference paper (Lakin, M. R. & Pitts, A. M. (2009) Resolving inductive definitions with binders in higher-order typed functional programming. InProceedings of the 18th European Symposium on Programming (ESOP 2009), Castagna, G. (ed), Lecture Notes in Computer Science, vol. 5502. Berlin, Germany: Springer-Verlag, pp. 47–61) and draws on material from the first author's PhD thesis (Lakin, M. R. (2010)An Executable Meta-Language for Inductive Definitions with Binders. University of Cambridge, UK).
Intralinguistic and extralinguistic variation factors in Old French negation withne-Ø, ne-mie, ne-pasandne-pointacross different text types
Authors: SCHØSLER LENE , VÖLKER HARALD
Published: December 2013

Old French sentential negation (NEG) represents an important morphosyntactic change that has been investigated by a large number of scholars from different theoretical approaches. From the 12th to the 14th (and mainly in the 13th) century, there are two variants of this variable in competition: NEG with onlyne(the older variant) and NEG withne+pas/mie/point, etc. The research presented in this paper has been motivated by the wish to find relevant factors for this variation in Old French. In order to identify factors of influence on the variable NEG with or withoutpas,mieandpoint, we analyse two subcorpora containing two different text types. The choice of the tested factors is rooted both in variational linguistics and in previous studies on Old French negation, implying (extralinguistic) diasystematic factors like diatopic and diastratic ones as well as intralinguistic factors like transitivity of the verb, word order and clause type. Main findings are the probable relevance of clause type and the influence of socially definable (diastratic) groups. Beyond this, the results across the two different text type are predominantly similar, but we found differences as well. This leads us to plead in favour of the importance of considering the factor text type while working on diachronic corpora.
The disastrous “sun ray” sign in cardiac magnetic resonance: an indicator of angiosarcoma
Authors: Akkaya Zehra , Gursoy Aysegul , Erden Ayse
Published: December 2013

Distinguishing the benign and malignant cardiac masses is usually a diagnostic challenge, and safe, non-invasive, and reliable techniques are necessary to avoid any delay in treatment. The previously described “sun ray” appearance is an important sign in the diagnosis of cardiac angiosarcoma, and in this report we present 3-T magnetic resonance imaging findings to distinguish the rare but fatal cardiac angiosarcoma.
Design and realization of a modular architecture for textual entailment
Authors: PADÓ SEBASTIAN , NOH TAE-GIL , STERN ASHER , WANG RUI , ZANOLI ROBERTO
Published: December 2013

A key challenge at the core of many Natural Language Processing (NLP) tasks is the ability to determine which conclusions can be inferred from a given natural language text. This problem, called theRecognition of Textual Entailment (RTE), has initiated the development of a range of algorithms, methods, and technologies. Unfortunately, research on Textual Entailment (TE), like semantics research more generally, is fragmented into studies focussing on various aspects of semantics such as world knowledge, lexical and syntactic relations, or more specialized kinds of inference. This fragmentation has problematic practical consequences. Notably, interoperability among the existing RTE systems is poor, and reuse of resources and algorithms is mostly infeasible. This also makes systematic evaluations very difficult to carry out. Finally, textual entailment presents a wide array of approaches to potential end users with little guidance on which to pick. Our contribution to this situation is the novel EXCITEMENT architecture, which was developed to enable and encourage the consolidation of methods and resources in the textual entailment area. It decomposes RTE into components with strongly typed interfaces. We specify (a) a modular linguistic analysis pipeline and (b) a decomposition of the ‘core’ RTE methods into top-level algorithms and subcomponents. We identify four major subcomponent types, including knowledge bases and alignment methods. The architecture was developed with a focus on generality, supporting all major approaches to RTE and encouraging language independence. We illustrate the feasibility of the architecture by constructing mappings of major existing systems onto the architecture. The practical implementation of this architecture forms the EXCITEMENT open platform. It is a suite of textual entailment algorithms and components which contains the three systems named above, including linguistic-analysis pipelines for three languages (English, German, and Italian), and comprises a number of linguistic resources. By addressing the problems outlined above, the platform provides a comprehensive and flexible basis for research and experimentation in textual entailment and is available as open source software under the GNU General Public License.
Individual Cognitive Behavioural Therapy for Psychosis (CBTp): A Systematic Review of Qualitative Literature
Authors: Wood Lisa , Burke Eilish , Morrison Anthony
Published: December 2013

Background: Individual Cognitive Behaviour Therapy for psychosis (CBTp) is the first line recommended psychological intervention for adults diagnosed with schizophrenia. However, little is yet known about service users’ subjective experiences of CBTp. Aims: This study aimed to conduct a systematic review of qualitative literature to examine service user perspective of CBTp. Method: A thematic synthesis of qualitative studies examining service users’ experiences of CBTp was conducted. A total of six studies were included in the analysis. Results: Three superordinate themes were identified: therapeutic alliance; facilitating change; and challenges of applying CBTp. Conclusion: Overall, CBTp is a helpful and acceptable therapeutic approach to service users. Developing a collaborative therapeutic relationship is essential. The applications of CBTp can be problematic and the therapist and client need to work together to overcome these difficulties.
When L1 becomes an L3: Do heritage speakers make better L3 learners?
Authors: POLINSKY MARIA
Published: December 2013

Heritage speakers who re-learn their childhood language in adulthood are an important group for the study of L3 acquisition. Such re-learners have selective advantages over other L2/L3 learners in phonetics/phonology, but lack a global advantage at re-learning the prestige variety of their L1. These learners show asymmetrical transfer effects in morphosyntax: transfer occurs only from the dominant language. Two tentative explanations for this asymmetry are suggested. First, re-learners may deploy the skills acquired in a classroom setting, where they have used only their dominant language. Second, re-learners may implicitly strive to increase the typological distance between their childhood language and the language of classroom instruction. These findings have implications for models of L3/Ln learning: the Cumulative Enhancement Model, the Typological Proximity Model, and the L2 Status Factor Model. The data discussed in this paper are most consistent with the latter model, but they also highlight the significance of the typological distance between languages under acquisition.
Dynamic Nanoimpedance Characterization of the Atomic Force Microscope Tip-Surface Contact
Authors: Tobiszewski Mateusz Tomasz , Zieliński Artur , Darowicki Kazimierz
Published: December 2013

Nanoimpedance measurements, using the dynamic impedance spectroscopy technique, were carried out during loading and unloading force of a probe on three kinds of materials of different resistivity. These materials were: gold, boron-doped diamond, and AISI 304 stainless steel. Changes of impedance spectra versus applied force were registered and differences in the tip-to-sample contact character on each material were revealed. To enable comparison between materials and phases, a new standardization method is proposed, which simulates conditions of initial contact.
Some Useful Sources
Authors: Chen Ci
Published: December 2013

There is now a considerable literature on poverty and inequality in the UK and Japan. This section details key publications, and particularly those which have addressed these issues from a comparative perspective. Details of relevant websites are also included.
Introduction: Comparative Perspectives on Poverty and Inequality: Japan and the United Kingdom
Authors: Pantazis Christina
Published: December 2013

Poverty and inequality appear to be intractable features of rich industrialised nations. It is a great paradox that despite rising prosperity in most advanced industrialised countries over the last two or three decades, poverty and inequality have remained stubbornly high and have even increased in the majority of rich countries (OECD, 2008, 2011). The United Kingdom and Japan are no exceptions to these trends. Despite having markedly different historical trajectories, there is evidence that the two societies are converging on the issue of these pressing social problems.
The Relationship Between Twin Language, Twins’ Close Ties, and Social Competence
Authors: Hayashi Chisato , Mikami Hiroshi , Nishihara Reiko , Maeda Chiho , Hayakawa Kazuo
Published: December 2013

This study investigated the relationship between twin language, twins’ close ties, and social competence in a prospective longitudinal study. We hypothesized that twins whose tie is close would be more likely to develop a twin language, and these twins would be less likely to develop social competence. In addition, we hypothesize that some environmental factors, such as having an older sibling, preschool attendance, zygosity, and sex are also related to twin language, twins’ close ties, and social competence. At baseline in 1999 a mailed questionnaire survey was conducted, and a follow-up questionnaire was distributed in 2004 among 958 mothers. As a result, 516 respondents returned the questionnaire (53.9%). In this study, we used 261 twin pairs aged from 6 to 12 years (school-age children) for analysis, excluding those with missing values. In the present study, we found that zygosity and sex were associated with twins’ close ties. Having an older sibling and preschool attendance did not affect the twins’ close tie, twin language, or social competence. One of the most important findings was that social competence was not affected directly by twins’ close tie, but was affected when a twin language was found.
Deprotonation of resorcinarenes by mono- and diamine bases: complexation and intermolecular interactions in the solid state
Authors: Beyeh N. Kodiah , Valkonen Arto , Rissanen Kari
Published: December 2013

The deprotonation of a resorcinarene by small organic bases results in 1 : 1 inclusion and 1 : 2 pseudo-capsular ion-pair complexes.
Effective catalytic disproportionation of aqueous H2O2with di- and mono-nuclear manganese(ii) complexes containing pyridine alcohol ligands
Authors: Zienkiewicz M. , Jabłońska-Wawrzycka A. , Szlachetko J. , Kayser Y. , Stadnicka K. , Sawka-Dobrowolska W. , Jezierska J. , Barszcz B. , Sá J.
Published: December 2013

The two novel manganese(ii) complexes were synthesized, thoroughly characterized, and tested in H2O2disproportionation reaction.
Testing flow-through air samplers for use in near-field vapour drift studies by measuring pyrimethanil in air after spraying
Authors: Geoghegan Trudyanne S. , Hageman Kimberly J. , Hewitt Andrew J.
Published: December 2013

Field evaluation of flow-through samplers indicates their viability as a wind-driven alternative to high-volume samplers in pesticide vapour drift studies.
Retrotaxis of human neutrophils during mechanical confinement inside microfluidic channels
Authors: Hamza Bashar , Wong Elisabeth , Patel Sachin , Cho Hansang , Martel Joseph , Irimia Daniel
Published: December 2013

We designed anin vitroassay for neutrophil migration and observed that more than 90% of human neutrophils have the ability to migrate persistently against chemoattractant gradients (retrotaxis), a process blocked after phagocytosis and restored by antioxidants and lipid mediators of inflammation resolution.
The kinetic mechanism of Human Thymidine Phosphorylase – a molecular target for cancer drug development
Authors: Deves Candida , Rostirolla Diana Carolina , Martinelli Leonardo Kras Borges , Bizarro Cristiano Valim , Santos Diogenes Santiago , Basso Luiz Augusto
Published: December 2013

A rapid-equilibrium random bi–bi kinetic mechanism and thermodynamics of binding of substrates and products are described for Human Thymidine Phosphorylase.
Sensitive and selective colorimetric sensing of Fe3+ion by using p-amino salicylic acid dithiocarbamate functionalized gold nanoparticles
Authors: Mehta Vaibhavkumar N. , Kailasa Suresh Kumar , Wu Hui-Fen
Published: December 2013

DTC-PAS-Au NPs successfully acted as probes for the selective and sensitive colorimetric sensing of Fe3+ions in biological samples.
Synthesis and characterisation of novel o-xylene-based P,E ligands
Authors: Allan Kathryn M. , Spencer John L.
Published: December 2013

A range of novel compounds containing an o-xylene backbone, for use as hybrid P,E ligands, have been synthesised from a common precursor.
Comparative analysis of cross strand aromatic–Phe interactions in designed peptide β-hairpins
Authors: Makwana Kamlesh Madhusudan , Mahalakshmi Radhakrishnan
Published: December 2013

Examination of the preferential interaction geometries of the aromatic amino acids Phe, Tyr and Trp with the benzyl ring of Phe in designed octapeptide hairpin scaffolds reveals stabilizing contributions of a Trp–Phe pair, even in amphipathic solvents.
Design, synthesis and binding properties of a fluorescent α9β1/α4β1integrin antagonist and its application as anin vivoprobe for bone marrow haemopoietic stem cells
Authors: Cao Benjamin , Hutt Oliver E. , Zhang Zhen , Li Songhui , Heazlewood Shen Y. , Williams Brenda , Smith Jessica A. , Haylock David N. , Savage G. Paul , Nilsson Susan K.
Published: December 2013

A fluorescent α9β1integrin antagonist with nanomolar binding affinities has been demonstrated to bind bone marrow haemopoietic stem and progenitor cellsin vivo.
A novel complementary absorbing donor–acceptor pair in block copolymers based on single material organic photovoltaics
Authors: Koyuncu Sermet , Wang Hsin-Wei , Liu Feng , Toga Kamil Bugra , Gu Weiyin , Russell Thomas P.
Published: December 2013

We report on the first synthesis of a highly crystalline donor–acceptor low band gap block copolymer by using diketopyrrolopyrrole (DPP) as a low band gap block and perylenebisimide (PDI) as a strong acceptor block.
The template role of caffeine in its one-step encapsulation in MOF NH2-MIL-88B(Fe)
Authors: Liédana Nuria , Lozano Pablo , Galve Alejandro , Téllez Carlos , Coronas Joaquín
Published: December 2013

A simple and efficient one-step encapsulation of caffeine was carried out in MOF NH2-MIL-88B(Fe) and compared to the traditional three-stage synthesis–activation–encapsulation procedure.
Operator pencil passing through a given operator
Authors: Biggs A. , Khudaverdian H. M.
Published: December 2013

Let Δ be a linear differential operator acting on the space of densities of a given weight λ0 on a manifold M. One can consider a pencil of operators \documentclass[12pt]{minimal}\begin{document}${\widehat{\Pi }}(\Delta )=\lbrace \Delta _{\lambda }\rbrace$\end{document}Π̂(Δ)={Δλ} passing through the operator Δ such that any Δλ is a linear differential operator acting on densities of weight λ. This pencil can be identified with a linear differential operator \documentclass[12pt]{minimal}\begin{document}$\widehat{\Delta }$\end{document}Δ̂ acting on the algebra of densities of all weights. The existence of an invariant scalar product in the algebra of densities implies a natural decomposition of operators, i.e., pencils of self-adjoint and anti-self-adjoint operators. We study lifting maps that are on one hand equivariant with respect to divergenceless vector fields, and, on the other hand, with values in self-adjoint or anti-self-adjoint operators. In particular, we analyze the relation between these two concepts, and apply it to the study of diff (M)-equivariant liftings. Finally, we briefly consider the case of liftings equivariant with respect to the algebra of projective transformations and describe all regular self-adjoint and anti-self-adjoint liftings. Our constructions can be considered as a generalisation of equivariant quantisation.
Competition between abstraction and exchange channels in H + HCN reaction: Full-dimensional quantum dynamics
Authors: Jiang Bin , Guo Hua
Published: December 2013

Dynamics of the title reaction is investigated on an ab initio based potential energy surface using a full-dimensional quantum wave packet method within the centrifugal sudden approximation. It is shown that the reaction between H and HCN leads to both the hydrogen exchange and hydrogen abstraction channels. The exchange channel has a lower threshold and larger cross section than the abstraction channel. It also has more oscillations due apparently to quantum resonances. Both channels are affected by long-lived resonances supported by potential wells. Comparison with experimental cross sections indicates underestimation of the abstraction barrier height.
Three-dimensional elastic constitutive relations of aligned carbon nanotube architectures
Authors: Handlin Daniel , Stein Itai Y. , Guzman de Villoria Roberto , Cebeci Hülya , Parsons Ethan M. , Socrate Simona , Scotti Stephen , Wardle Brian L.
Published: December 2013

Tailorable anisotropic intrinsic and scale-dependent properties of carbon nanotubes (CNTs) make them attractive elements in next-generation advanced materials. However, in order to model and predict the behavior of CNTs in macroscopic architectures, mechanical constitutive relations must be evaluated. This study presents the full stiffness tensor for aligned CNT-reinforced polymers as a function of the CNT packing (up to ∼20 vol. %), revealing noticeable anisotropy. Finite element models reveal that the usually neglected CNT waviness dictates the degree of anisotropy and packing dependence of the mechanical behavior, rather than any of the usually cited aggregation or polymer interphase mechanisms. Combined with extensive morphology characterization, this work enables the evaluation of structure-property relations for such materials, enabling design of aligned CNT material architectures.
Communication: Theoretical study of ThO for the electron electric dipole moment search
Authors: Skripnikov L. V. , Petrov A. N. , Titov A. V.
Published: December 2013

An experiment to search for the electron electric dipole moment (eEDM) on the metastable H3Δ1 state of ThO molecule was proposed and now prepared by the ACME Collaboration [http://www.electronedm.org]. To interpret the experiment in terms of eEDM and dimensionless constant kT, P characterizing the strength of the T,P-odd pseudoscalar–scalar electron–nucleus neutral current interaction, an accurate theoretical study of an effective electric field on electron, Eeff, and a parameter of the T,P-odd pseudoscalar–scalar interaction, WT, P, in ThO is required. We report our results for Eeff (84 GV/cm) and WT, P (116 kHz) together with the hyperfine structure constant, molecule frame dipole moment, and H3Δ1 → X1Σ+ transition energy, which can serve as a measure of reliability of the obtained Eeff and WT, P values. Besides, our results include a parity assignment and evaluation of the electric-field dependence for the magnetic g factors in the Ω-doublets of H3Δ1.
A novel thermally biased mechanical energy conversion cycle
Authors: McKinley Ian M. , Goljahi Sam , Lynch Christopher S. , Pilon Laurent
Published: December 2013

This paper demonstrates a new power cycle for direct conversion of mechanical energy into electrical energy under a thermal bias. The cycle consisted sequentially of (i) an electric poling process under zero stress, (ii) an isoelectric process consisting of applying a uniaxial compressive stress σH followed by (iii) an electric de-poling process under constant compressive stress, and finally (iv) an isoelectric process consisting of removing the compressive stress. The new cycle was performed at constant bias-temperature Tb. It was demonstrated on [001]-poled 0.72PbMg1∕3Nb2∕3O3-0.28PbTiO3 single crystals. The power density increased with increasing cycle frequency and compressive stress for frequency up to 1 Hz. Maximum energy and power densities of 44 J/l/cycle and 44 W/l were achieved at 1 Hz for bias-temperature Tb of 80 °C and electric field cycled between 0.2 and 0.8 MV/m with compressive stress σH = 25.13 MPa. This was attributed to a tetragonal-monoclinic-orthorhombic phase transition sequence. The material efficiency reached up to 87% and exceeded that of a similar thermomechanical power cycle performed on pyroelectric material. Finally, a physical model predicting the power density was derived and yielded accurate predictions of experimental data for all bias-temperatures considered and cycle frequency up to 1 Hz.
Enhanced ferroelectric and dielectric properties of (111)-oriented highly cation-ordered PbSc0.5Ta0.5O3 thin films
Authors: Chopra Anuj , Birajdar Balaji I. , Kim Yunseok , Alexe Marin , Hesse Dietrich
Published: December 2013

Cation-ordered (111)-oriented epitaxial PbSc0.5Ta0.5O3 (PST) thin films were deposited by pulsed laser deposition on SrRuO3-electroded SrTiO3 (111) substrates at three different temperatures of 525 °C, 550 °C, and 575 °C. All the films were well crystalline and (111)-oriented at all the three growth temperatures; however, the films deposited at the temperatures other than 550 °C exhibited the presence of a pyrochlore phase. X-ray diffraction analysis and transmission electron microscopy measurements revealed that the films were epitaxial and highly cation-ordered. In comparison to (001)-oriented PST films, (111)-oriented films on SrRuO3/SrTiO3 (111) exhibited enhanced ferroelectric and dielectric properties with a broad size distribution of cation-ordered domains (5–100 nm). At a measurement temperature of 100 K, the remnant polarization of PST (111) films is almost √3 times larger than the remnant polarization observed for (001)-oriented PST films, which is attributed to the (111) orientation of the films, as the spontaneous polarization in PST lies close to the [111] direction. The observed dielectric constant and loss at 1 kHz were around 1145 and 0.11, respectively. The dielectric constant is thus almost three times higher than for previously reported (001)-oriented PST thin films, most probably due to the enhancement in cation-ordering.
The backward phase flow method for the Eulerian finite time Lyapunov exponent computations
Authors: Leung Shingyu
Published: December 2013

We propose a simple Eulerian approach to compute the moderate to long time flow map for approximating the Lyapunov exponent of a (periodic or aperiodic) dynamical system. The idea is to generalize a recently proposed backward phase flow method which is specially designed for long time level set propagation. Unlike the original phase flow method or the backward phase flow method, which is applicable only to autonomous systems, the current approach can also be applied to any time-dependent (periodic or aperiodic) flow. We will discuss the stability of the proposed method. Numerical examples will be given to demonstrate the effectiveness of the algorithm.
Modelization of structural changes in ultra low k materials during ultraviolet cure
Authors: Imbert G. , Vo-Than D. , Trouiller C. , Lorut F.
Published: December 2013

As of 45 nm node, ultralow k (ULK) materials (εr < 2.55) are widely used in microelectronic interconnects to reduce signal propagation delay. In order to get such low dielectric constant, most of these ULK are obtained using subtractive method: after co-deposition of matrix and porogen a UV cure process is used to remove labile species (porogen). During this process, porosity is created and films are densified as shrinkage increases. This paper presents an in-depth study of the UV cure process. Two kinetic models are presented to describe shrinkage rate: the nth order and the autocatalytic model. These models also used to describe photo-polymerization shrinkage-strain of dental composite, gives predictions that are in good agreement with experimental data. We find that nth-order model is best suited to describe ULK transformations during UV cure process. CHx bonds loss and carbon content can also be modeled using same kinetic model. In order to be able to build the model, initial SiOCH-CxHy film has to be over-cured to determine the maximum conversion that film can reach when submitted to extra-long cure times. Results show that such SiOCH materials have to be cured more than 250 times their nominal cure time to reach maximum shrinkage (∼50%) and a complete loss of carbon, making them looking like SiO2. When structural changes are observed at different temperature, activation energy of reactions can be determined. In this way, shrinkage reaction has an activation energy close to 1000–1100 kJ/mol and CHx bonds or carbon loss reactions have activation energy in the range of 250–400 kJ/mol, which is pretty close to C-H binding energy.
Integrated vertical microcavity using a nano-scale deformation for strong lateral confinement
Authors: Mai Lijian , Ding Fei , Stöferle Thilo , Knoll Armin , Jan Offrein Bert , Mahrt Rainer F.
Published: December 2013

We report on the realization of a solid state Fabry-Pérot-like microcavity that uses a small Gaussian-shaped deformation inside the cavity to achieve strong lateral photon confinement on the order of the wavelength. Cavities with a mode volume V < 0.4 μm3 and a quality factor Q > 1000 are fabricated by means of focused ion beam milling, removing the necessity for etched sidewalls as required for micropillar cavities. Perylene-diimide dye doped polystyrene was embedded in the microcavity and probed by time-resolved microphotoluminescence. A Purcell enhancement of the spontaneous emission rate by a factor of 3.5 has been observed at room temperature.
Optical properties of two-dimensional metamaterial photonic crystals
Authors: Mejía-Salazar J. R.
Published: December 2013

In the present work, we theoretically study a 2D photonic crystal (PC) comprised by double negative (DNG) metamaterial cylinders, showing that such a system presents a superior light-matter interaction when compared with their single negative (SNG) plasmonic PC counterparts, suggesting a route to enhance the performance of sensors and photovoltaic cells. On the other hand, we have observed that depending on the frequency, the mode symmetry resembles either the case of SNG electric (SNG-E) or SNG magnetic (SNG-M) PC, suggesting that either the electric or magnetic character of the DNG metamaterial dominates in each case.
Determination of the Pt spin diffusion length by spin-pumping and spin Hall effect
Authors: Zhang Wei , Vlaminck Vincent , Pearson John E. , Divan Ralu , Bader Samuel D. , Hoffmann Axel
Published: December 2013

The spin diffusion length of Pt at room temperature and at 8 K is experimentally determined via spin pumping and spin Hall effect in permalloy/Pt bilayers. Voltages generated during excitation of ferromagnetic resonance from the inverse spin Hall effect and anisotropic magnetoresistance effect were investigated with a broadband approach. Varying the Pt layer thickness gives rise to an evolution of the voltage line shape due to the superposition of the above two effects. By studying the ratio of the two voltage components with the Pt layer thickness, the spin diffusion length of Pt can be directly extracted. We obtain a spin diffusion length of ∼1.2 nm at room temperature and ∼1.6 nm at 8 K.
Magnetic induction measurements using an all-optical 87Rb atomic magnetometer
Authors: Wickenbrock Arne , Tricot François , Renzoni Ferruccio
Published: December 2013

In this work we propose, and experimentally demonstrate, the use of a self-oscillating all-optical atomic magnetometer for magnetic induction measurements. Given the potential for miniaturization of atomic magnetometers, and their extreme sensitivity, the present work shows that atomic magnetometers may play a key role in the development of instrumentation for magnetic induction tomography.
Time-resolved observation of fast domain-walls driven by vertical spin currents in short tracks
Authors: Sampaio Joao , Lequeux Steven , Metaxas Peter J. , Chanthbouala Andre , Matsumoto Rie , Yakushiji Kay , Kubota Hitoshi , Fukushima Akio , Yuasa Shinji , Nishimura Kazumasa , Nagamine Yoshinori , Maehara Hiroki , Tsunekawa Koji , Cros Vincent , Grollier Julie
Published: December 2013

We present time-resolved measurements of the displacement of magnetic domain-walls (DWs) driven by vertical spin-polarized currents in track-shaped magnetic tunnel junctions. In these structures, we observe very high DW velocities (600 m/s) at current densities below 107 A/cm2. We show that the efficient spin-transfer torque combined with a short propagation distance allows avoiding the Walker breakdown process and achieving deterministic, reversible, and fast (≈1 ns) DW-mediated switching of magnetic tunnel junction elements, which is of great interest for the implementation of fast DW-based spintronic devices.
Interprovincial Return Migration in China: Individual and Contextual Determinants in Sichuan Province in the 1990S
Authors: Chunyu Miao David , Liang Zai , Wu Yingfeng
Published: December 2013

China's massive volume of and dramatic increase in migration have stimulated increasing research in this area. However, researchers have not paid sufficient attention to return migration until recently when the issue of migrant labor shortage in Southern China has been linked to return migration back to the rural areas. Taking advantage of information contained in the 1995 China 1% Population Sample Survey and the 2000 China Census, this paper provides a systematic analysis of interprovincial return migration to Sichuan province, one of the most important migrant-sending provinces in China. We focus on return migrant selectivity, the impact of local labor-market conditions and migration networks on return migration, and nonfarm work participation among return migrants. Return migration in the late 1990s shows positive selection on education and return migrants are more likely to engage in nonfarm work. The pattern for the early 1990s is just the opposite of what is observed in the late 1990s. Our multilevel models show that labor-market conditions as well as migration networks in destination areas play important roles in the return migration process. Policy implications of this trend of return migration are discussed.
Do History and Geography Matter? Regional Unemployment Dynamics in a Resource-Dependent Economy: Evidence from Western Australia, 1984–2011
Authors: Plummer Paul , Tonts Matthew
Published: December 2013

Conceptual and methodological differences notwithstanding, both the ‘new’ economic geography and evolutionary economic geography insist that both history and geography matter when accounting for the changing spatial distribution of economic activities. To date, discourse has been conducted largely at a theoretical level, with few attempts to evaluate the empirical validity of either of these competing claims about the dynamics of the capitalist space economy. In this paper we contribute to this evolving discourse by utilizing a dynamic econometric perspective to empirically test the key notions of path dependence, place dependence, and equilibrium dependence in the context of a ‘peripheral’ resource dependent and export-oriented economy: Western Australia, 1984–2011. We find evidence of ‘weak’ path dependence in the evolution of local unemployment rates, with a small number of local labor markets exhibiting ‘strong’ equilibrium dependence. Furthermore, we find evidence of ‘place’ dependence, particularly between metropolitan and nonmetropolitan labor markets, suggesting the existence of a ‘patchwork economy’.
Politics and Possibility on the Metropolitan Edge: The Scale of Social Movement Space in Exurbia
Authors: Schafran Alex , Lopez Oscar Sosa , Gin June L
Published: December 2013

Both the suburbanization of poverty and the growth of suburban social movements have been the focus of much academic discussion of late, even if these two discussions are not necessarily linked. One area that has been relatively underresearched when it comes to both phenomena are exurban regions, critical spaces of change and crisis, in particular in upmarket regions like those in Northern and Southern California. This paper presents a case study of the ‘social movement space’ of eastern Contra Costa County, on the edge of the San Francisco Bay Area. It argues that not only did propoor, social-justice-oriented movements arise over the past decade in response to changing geography, they exhibited a form of ‘scalar promiscuity’ which differs from the regionalization of social movements or other forms of ‘scale jumping’ well known in the literature.