bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetic field concentration assisted by epsilon-near-zero media
Authors: Liberal Iñigo , Li Yue , Engheta Nader 
Published: February 2017

Strengthening the magnetic response of matter at optical frequencies is of fundamental interest, as it provides additional information in spectroscopy, as well as alternative mechanisms to manipulate light at the nanoscale. Here, we demonstrate theoretically that epsilon-near-zero (ENZ) media can enhance the magnetic field concentration capabilities of dielectric resonators. We demonstrate that the magnetic field enhancement factor is unbounded in theory, and it diverges as the size of the ENZ host increases. In practice, the maximal enhancement factor is limited by dissipation losses in the host, and it is found via numerical simulations that ENZ hosts with moderate losses can enhance the performance of a circular dielectric rod resonator by around one order of magnitude. The physical mechanism behind this process is the strongly inhomogeneous magnetic field distributions induced by ENZ media in neighbouring dielectrics. We show that this is an intrinsic property of ENZ media, and that the occurrence of resonant enhancement is independent of the shape of the host. These results might find applications in spectroscopy, in sensing, in light emission and, in general, in investigating light–matter interactions beyond electric dipole transitions.
This article is part of the themed issue ‘New horizons for nanophotonics’.
Electrical tuning of the polarization state of light using graphene-integrated anisotropic metasurfaces
Authors: Dutta-Gupta Shourya , Dabidian Nima , Kholmanov Iskandar , Belkin Mikhail A. , Shvets Gennady 
Published: February 2017

Plasmonic metasurfaces have been employed for moulding the flow of transmitted and reflected light, thereby enabling numerous applications that benefit from their ultra-thin sub-wavelength format. Their appeal is further enhanced by the incorporation of active electro-optic elements, paving the way for dynamic control of light's properties. In this paper, we realize a dynamic polarization state generator using a graphene-integrated anisotropic metasurface (GIAM) that converts the linear polarization of the incident light into an elliptical one. This is accomplished by using an anisotropic metasurface with two principal polarization axes, one of which possesses a Fano-type resonance. A gate-controlled single-layer graphene integrated with the metasurface was employed as an electro-optic element controlling the phase and intensity of light polarized along the resonant axis of the GIAM. When the incident light is polarized at an angle to the resonant axis of the metasurface, the ellipticity of the reflected light can be dynamically controlled by the application of a gate voltage. Thus accomplished dynamic polarization control is experimentally demonstrated and characterized by measuring the Stokes polarization parameters. Large changes of the ellipticity and the tilt angle of the polarization ellipse are observed. Our measurements show that the tilt angle can be changed from positive values through zero to negative values while keeping the ellipticity constant, potentially paving the way to rapid ellipsometry and other characterization techniques requiring fast polarization shifting.
This article is part of the themed issue ‘New horizons for nanophotonics’.
Third-harmonic generation from Mie-type resonances of isolated all-dielectric nanoparticles
Authors: Melik-Gaykazyan Elizaveta V. , Shcherbakov Maxim R. , Shorokhov Alexander S. , Staude Isabelle , Brener Igal , Neshev Dragomir N. , Kivshar Yuri S. , Fedyanin Andrey A. 
Published: February 2017

Subwavelength silicon nanoparticles are known to support strongly localized Mie-type modes, including those with resonant electric and magnetic dipolar polarizabilities. Here we compare experimentally the efficiency of the third-harmonic generation from isolated silicon nanodiscs for resonant excitation at the two types of dipolar resonances. Using nonlinear spectroscopy, we observe that the magnetic dipolar mode yields more efficient third-harmonic radiation in contrast to the electric dipolar (ED) mode. This is further supported by full-wave numerical simulations, where the volume-integrated local fields and the directly simulated nonlinear response are shown to be negligible at the ED resonance compared with the magnetic one.
This article is part of the themed issue ‘New horizons for nanophotonics’.
Double-resonant enhancement of third-harmonic generation in graphene nanostructures
Authors: You Jian Wei , You Jie , Weismann Martin , Panoiu Nicolae C. 
Published: February 2017

Intriguing and unusual physical properties of graphene offer remarkable potential for advanced, photonics-related technological applications, particularly in the area of nonlinear optics at the deep-subwavelength scale. In this study, we use a recently developed numerical method to illustrate an efficient mechanism that can lead to orders of magnitude enhancement of the third-harmonic generation in graphene diffraction gratings. In particular, we demonstrate that by taking advantage of the geometry dependence of the resonance wavelength of localized surface-plasmon polaritons of graphene ribbons and discs one can engineer the spectral response of graphene gratings so that strong plasmonic resonances exist at both the fundamental frequency and third-harmonic (TH). As a result of this double-resonant mechanism for optical near-field enhancement, the intensity of the TH can be increased by more than six orders of magnitude.
This article is part of the themed issue ‘New horizons for nanophotonics’.
Chiral optical fields: a unified formulation of helicity scattered from particles and dichroism enhancement
Authors: Nieto-Vesperinas Manuel 
Published: February 2017

We establish a general unified formulation which, using the optical theorem of electromagnetic helicity, shows that dichorism is a phenomenon arising in any scattering—or diffraction—process, elastic or not, of chiral electromagnetic fields by objects either chiral or achiral. It is shown how this approach paves the way to overcoming well-known limitations of standard circular dichroism, like its weak signal or the difficulties of using it with magnetodielectric particles. Based on the angular spectrum, representation of optical fields with only right circular or left circular plane waves, we introduce beams with transverse elliptic polarization and possessing a longitudinal component. Then, our formulation for general optical fields shows how to enhance the extinction rate of incident helicity (and therefore the dichroism signal) versus that of energy of the light scattered or emitted by a particle, or vice versa.
This article is part of the themed issue ‘New horizons for nanophotonics’.
Multipolar interference effects in nanophotonics
Authors: Liu Wei , Kivshar Yuri S. 
Published: February 2017

Scattering of electromagnetic waves by an arbitrary nanoscale object can be characterized by a multipole decomposition of the electromagnetic field that allows one to describe the scattering intensity and radiation pattern through interferences of dominating multipole modes excited. In modern nanophotonics, both generation and interference of multipole modes start to play an indispensable role, and they enable nanoscale manipulation of light with many related applications. Here, we review the multipolar interference effects in metallic, metal–dielectric and dielectric nanostructures, and suggest a comprehensive view on many phenomena involving the interferences of electric, magnetic and toroidal multipoles, which drive a number of recently discussed effects in nanophotonics such as unidirectional scattering, effective optical antiferromagnetism, generalized Kerker scattering with controlled angular patterns, generalized Brewster angle, and non-radiating optical anapoles. We further discuss other types of possible multipolar interference effects not yet exploited in the literature and envisage the prospect of achieving more flexible and advanced nanoscale control of light relying on the concepts of multipolar interference through full phase and amplitude engineering.
This article is part of the themed issue ‘New horizons for nanophotonics’.
Creating a Community of Data Champions
Authors: Higman Rosie , Teperek Marta , Kingsley Danny 
Published: February 2017

AbstractResearch Data Management (RDM) presents an unusual challenge for service providers in Higher Education. There is increased awareness of the need for training in this area but the nature of discipline-specific practices involved make it difficult to provide training across a multi-disciplinary organisation. Whilst most UK universities now have a research data team of some description, they are often small and rarely have the resources necessary to provide targeted training to the different disciplines and research career stages that they are increasingly expected to support.This practice paper describes the approach taken at the University of Cambridge to address this problem by creating a community of Data Champions. This collaborative initiative, working with researchers to provide training and advocacy for good RDM practice, allows for more discipline-specific training to be given, researchers to be credited for their expertise and an opportunity for those interested in RDM to exchange knowledge with others. The ‘community of practice’ model has been used in many sectors, including Higher Education, to facilitate collaboration across organisational units and this initiative will adopt some of the same principles to improve communication across a decentralised institution. The Data Champions initiative at Cambridge was launched in September 2016 and this paper reports on the early months, plans for building the community in the future and the possible risks associated with this approach to providing RDM services.
Reason’s Enemy Is Not Emotion: Engagement of Cognitive Control Networks Explains Biases in Gain/Loss Framing
Authors: Li Rosa , Smith David V. , Clithero John A. , Venkatraman Vinod , Carter R. McKell , Huettel Scott A. 
Published: February 2017

AbstractIn the classic gain/loss framing effect, describing a gamble as a potential gain or loss biases people to make risk-averse or risk-seeking decisions, respectively. The canonical explanation for this effect is that frames differentially modulate emotional processes – which in turn leads to irrational choice behavior. Here, we evaluate the source of framing biases by integrating functional magnetic resonance imaging (fMRI) data from 143 human participants performing a gain/loss framing task with meta-analytic data from over 8000 neuroimaging studies. We found that activation during choices consistent with the framing effect were most correlated with activation associated with the resting or default brain, while activation during choices inconsistent with the framing effect most correlated with the task-engaged brain. Our findings argue against the common interpretation of gain/loss framing as a competition between emotion and control. Instead, our study indicates that this effect results from differential cognitive engagement across decision frames.Significance StatementThe biases frequently exhibited by human decision-makers have often been attributed to the presence of emotion. Using a large fMRI sample and analysis of whole-brain networks defined with the meta-analytic tool Neurosynth, we find that neural activity during frame-biased decisions are more significantly associated with default behaviors (and the absence of executive control) than with emotion. These findings point to a role for neuroscience in shaping longstanding psychological theories in decision science.
On the relationship between tumour growth rate and survival in non-small cell lung cancer
Authors: Mistry Hitesh B. 
Published: February 2017

AbstractA recurrent question within oncology drug development is predicting phase III outcome for a new treatment using early clinical data. One approach to tackle this problem has been to derive metrics from mathematical models that describe tumour size dynamics termed re-growth rate and time to tumour re-growth. They have shown to be strong predictors of overall survival in numerous studies but there is debate about how these metrics are derived and if they are more predictive than empirical end-points. This work explores the issues raised in using model-derived metric as predictors for survival analyses. Re-growth rate and time to tumour re-growth were calculated for three large clinical studies by forward and reverse alignment. The latter involves re-aligning patients to their time of progression. Hence it accounts for the time taken to estimate re-growth rate and time to tumour re-growth but also assesses if these predictors correlate to survival from the time of progression. We found that neither re-growth rate nor time to tumour re-growth correlated to survival using reverse alignment. This suggests that the dynamics of tumours up until disease progression has no relationship to survival post progression. For prediction of a phase III trial we found the metrics performed no better than empirical end-points. These results highlight that care must be taken when relating dynamics of tumour imaging to survival and that bench-marking new approaches to existing ones is essential.
Local interactions lead to spatially correlated gene expression levels in bacterial groups
Authors: Vliet Simon van , Co Alma Dal , R. Winkler Annina , Spriewald Stefanie , Stecher Bärbel , Ackermann Martin 
Published: February 2017

AbstractMany bacteria live in spatially structured assemblies where the microenvironment of a cell is shaped by the activities of its neighbors. Bacteria regulate their gene expression based on the inferred state of the environment. This raises the question whether the phenotypes of neighboring cells can become correlated through interactions via the shared microenvironment. Here, we addressed this question by following gene expression dynamics inEscherichia colimicrocolonies. We observed strong spatial correlations in the expression dynamics for pathways involved in toxin production, SOS-stress response, and metabolism. These correlations can partly be explained by a combination of shared lineage history and spatial gradients in the colony. Interestingly, we also found evidence for cell-cell interactions in SOS-stress response, methionine biosynthesis and overall metabolic activity. Together our data suggests that intercellular feedbacks can couple the phenotypes of neighboring cells, raising the question whether gene-regulatory networks have evolved to spatially organize biological functions.
Stochastic model of contact inhibition and the proliferation of melanomain situ
Authors: César Cafundó Morais Mauro , Stuhl Izabella , Sabino Alan U , Lautenschlager Willian W , Queiroga Alexandre S , Tortelli Tharcisio Citrangulo , Chammas Roger , Suhov Yuri , Ramos Alexandre F 
Published: February 2017

ABSTRACTContact inhibition is a central feature orchestrating cell proliferation in culture experiments; its loss is associated with malignant transformation and tumorigenesis. We performed a co-culture experiment with human metastatic melanoma cell line (SKMEL-147) and immortalized keratinocyte cells (HaCaT). After 8 days a spatial pattern was detected, characterized by the formation of clusters of melanoma cells surrounded by keratinocytes constraining their proliferation. In addition, we observed that the proportion of melanoma cells within the total population has increased. To explain our results we propose a spatial stochastic model (following a philosophy of the Widom-Rowlinson model from Statistical Physics and Molecular Chemistry) which considers cell proliferation, death, migration, and cell-to-cell interaction through contact inhibition. Our numerical simulations demonstrate that loss of contact inhibition is a sufficient mechanism, appropriate for an explanation of the increase in the proportion of tumor cells and generation of spatial patterns established in the conducted experiments.
Measuring market risk for an agricultural exporter firm: a Copula approach
Authors: Fernández Julián 
Published: February 2017

Purpose
The purpose of this paper is to analyse the effect of market risk on the revenues perceived by an agricultural producer, namely, a coffee exporter firm.

Design/methodology/approach
To model this risk, copula models and extreme value theory are used to perform more robust estimations, which take into account the multivariate dependence between the risk factors. As a final point, different quantitative measures of risk, such as the value at risk and the expected shortfall, are estimated as an indicator of the maximum expected loss.

Findings
One of the principal findings is that for an agricultural exporter firm, there is an optimal decision between exporting to another country and selling the commodity in the national market. The choice regarding the levels exported will determine the firm’s amount of risk and expected return.

Research limitations/implications
One of the limitations found in modelling the risk/return of the firm is the data. Not much data on the structure of the firm can be found, and many of the firms are averse to providing such information.

Practical implications
The purpose of the paper is to create a measure of risk to analyse the future of the firm, generating a measure of expected risk and return that takes into account the uncertainty of the future. The applications can be applied to measure the risk of a potential investment and real option valuation.

Originality/value
This paper applied multiple coherent measures of financial risk to an agricultural commodity exporter firm. This can be novel, especially in the context of a non-financial firm.
Efficiency and exogenous factors: evidence from Spanish tourism regions
Authors: Solana Ibáñez José , Para González Lorena , de Nieves Nieto Carmen 
Published: February 2017

PurposeThe purpose of this paper is to analyse the performance of Spanish tourism regions for the 2008-2011 period, to obtain a ranking of efficiency and to examine the hypothesis that the efficiency of these regions is determined by a group of contextual variables.Design/methodology/approachIn contrast with monitoring reports based on descriptive methods, this paper uses data envelopment analysis (DEA) methodology and bootstrap semiparametric procedures to correct inherent bias. The significance of a group of exogenous factors is investigated and the importance of each determinant is ordered by its elasticity.FindingsThe ranking obtained by radial DEA models and by bias-corrected ones describes two remarkably different settings. The exogenous variables influence hypothesis and confirmed: that estimated coefficients are of the correct sign and statistically significant at 5 per cent.Originality/valueThe statistical significance of the potential attractors can offer an interesting tool for strategic decisions. The two-stage procedure employed has supposed a turning point in the methodology and there are only a handful of very recent studies of this type in the literature on tourism destination performance. In this sense, no previous work has considered the returns to scale test or the separability assumption. Following United Nations of World Tourism Organization recommendations, it is essential to move towards responsible tourism in all aspects. Some final considerations about the link between performance and sustainability of the Spanish tourist model are addressed in this study.
A framework for benchmarking the strategic position of bond markets in the competing environment
Authors: Sukcharoensin Sorasart 
Published: February 2017

Purpose
The purpose of this paper is to develop a benchmarking framework for identifying different indicators and their importance in forming the strategic position of Thai bond markets in competitive economies using Strategic Position and Action Evaluation (SPACE) matrix framework.

Design/methodology/approach
The Delphi approach is deployed for indicator selection and the framework validation. A questionnaire survey is then used to assess the importance of different factors determining the strategic bond market development and competitiveness using the Analytic Hierarchy Process (AHP) model.

Findings
A group of experienced bond market experts assign different levels of importance for each key factor under a given dimension to reach consensus. The results reveal that there are 17 factors affecting the strategic development and competitiveness of the bond market. Among four aspects under the framework, the financial strength dimension is considered by the experts as the most dominant aspect to strategic bond market development, followed by competitive advantage, industry strength, and environment stability, respectively.

Practical implications
The benchmarking framework developed in this study is useful for guiding measurement and assessment of the strategic position of bond markets in the competing environment.

Originality/value
The author proposes for the first time a conceptual framework based on macro-level data to assess the strategic bond market development and competitiveness using SPACE matrix method. The study employs the Delphi’s technique and in-depth interview with bond market experts to build indicators for each dimension under the framework. Second, this paper also applies the AHP to discover the order of relative importance for the indicators identified by the experts through pairwise comparison to reach consensus, which has never been conducted before.
A framework to enhance agile manufacturing system
Authors: Sindhwani Rahul , Malhotra Vasdev 
Published: February 2017

Purpose
The purpose of this paper is to identify and analyze the interactions among different enablers of agile manufacturing system (AMS). The existing enablers available in the past literature are scattered and not able to meet specific requirements of the customers. So, it becomes a necessity to encapsulate these enablers in appropriate proportions to enable traditional organizations to AMS. To fill this gap total interpretive structural modeling (TISM) and MICMAC analysis-based framework model have been developed to understand the mutual interactions between among the enablers.

Design/methodology/approach
Identification of enablers followed by application of TISM, which is an innovative version of ISM and MICMAC analysis, is used to study and analyze the mutual interactions between identified enablers.

Findings
The result reveals that top management support, organizational structure and information technology integration have strong driving power and weak dependence power and are at the lowest level in the TISM model hierarchy, while the outcome enablers of AMS have low-driving power but have high-dependence power.

Research limitations/implications
This model is developed on the basis of inputs from few experts and may not reflect the opinion of whole industry community.

Practical implications
Top management must stress on enablers having strong driving power for efficient implementation of AMS. Managers in the area of manufacturing may drive useful insights from the empirical study presented in this paper. Managers should plan an effective strategy for proper implementation of AMS which makes organization more agile, productive, competitive and profitable.

Originality/value
TISM-based framework structural model has been proposed for industry or organization which is a new effort for implementation of AMS.