114 research outputs found

    What is the Brillouin Zone of an Anisotropic Photonic Crystal?

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    The concept of the Brillouin zone (BZ) in relation to a photonic crystal fabricated in an optically anisotropic material is explored both experimentally and theoretically. In experiment, we used femtosecond laser pulses to excite THz polaritons and image their propagation in lithium niobate and lithium tantalate photonic crystal (PhC) slabs. We directly measured the dispersion relation inside PhCs and observed that the lowest bandgap expected to form at the BZ boundary forms inside the BZ in the anisotropic lithium niobate PhC. Our analysis shows that in an anisotropic material the BZ - defined as the Wigner-Seitz cell in the reciprocal lattice - is no longer bounded by Bragg planes and thus does not conform to the original definition of the BZ by Brillouin. We construct an alternative Brillouin zone defined by Bragg planes and show its utility in identifying features of the dispersion bands. We show that for an anisotropic 2D PhC without dispersion, the Bragg plane BZ can be constructed by applying the Wigner-Seitz method to a stretched or compressed reciprocal lattice. We also show that in the presence of the dispersion in the underlying material or in a slab waveguide, the Bragg planes are generally represented by curved surfaces rather than planes. The concept of constructing a BZ with Bragg planes should prove useful in understanding the formation of dispersion bands in anisotropic PhCs and in selectively tailoring their optical properties.Comment: 9 pages, 6 figure

    Entrepreneurial Intention among Undergraduates: Review of Literature

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    Purpose of this study is to formulate the unique model to the entrepreneurial intention among undergraduates. We reviewed the existing studies in the field of entrepreneurial intention in the Asia, Europe, Africa and cross cultural perspective. Based on the review of literatures in the entrepreneurial intention, we have formulated the unique model as entrepreneurial Intention for entrepreneurial Career. Based on the Model creation, the entrepreneurial motivation is the recognized as the key fact to enhance the entrepreneurial intention among undergraduates in the globalized level. Meanwhile, this model is unique and highly suitable to the Asian perspective.  Researchers or scholars in the field of entrepreneurship can utilize this model to predict the influence of the entrepreneurial motivation on the entrepreneurial intention among undergraduates. Key Words: Entrepreneurial Motivation, Entrepreneurial Intention, and Undergraduates

    THz generation using a reflective stair-step echelon

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    We present a novel method for THz generation in lithium niobate using a reflective stair-step echelon structure. The echelon produces a discretely tilted pulse front with less angular dispersion compared to a high groove-density grating. The THz output was characterized using both a 1-lens and 3-lens imaging system to set the tilt angle at room and cryogenic temperatures. Using broadband 800 nm pulses with a pulse energy of 0.95 mJ and a pulse duration of 70 fs (24 nm FWHM bandwidth, 39 fs transform limited width), we produced THz pulses with field strengths as high as 500 kV/cm and pulse energies as high as 3.1 ÎĽ\muJ. The highest conversion efficiency we obtained was 0.33%. In addition, we find that the echelon is easily implemented into an experimental setup for quick alignment and optimization.Comment: 19 pages, 4 figure

    Financial Stress and Personal Characteristics of the School Teachers: Evidence from Sri Lanka

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    The primary aim of the study is to find out the significant mean difference in financial stress among personal characteristics of the school teachers as gender, age, family size, subjects for teaching, educational qualification, and work experience.  The study employs independent samples t- test and one-way ANOVA (f-test) to test the operational hypotheses. The survey method used in this study is a questionnaire and a total of 360 usable responses were obtained using simple random sampling technique. Findings revealed that, there is a significant mean difference in financial stress among subject for teaching, educational qualification and working experience of the school teachers in the northern province of Sri Lanka. In contrast, we found that, there is no significant mean difference in financial stress among gender, age level and family size. Further, we suggested that, Governmental bodies should have the responsibility to control the financial instability in the Northern Province and as well as all island through the better policy drafts in the monetary and fiscal aspects. Key Words: Financial Stress, Personal characteristics, Northern Province, Sri Lanka and School Teacher

    Pay satisfaction and Financial Stress: A study of the school Teachers in the Northern Province, Sri Lanka

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    The primary aim of the study is to find out the impact or influence of pay satisfaction on financial stress among the school teachers in Northern Province, Sri Lanka. Further, secondary objective is to suggest the government authoritative bodies to reduce the financial stress through the better level of pay satisfaction, which will give the long term value to the Northern Province, Sri Lanka in terms of social, economical and political development. The study employs Multiple Regression Analysis to test the operational hypotheses. The survey method used in this study is a questionnaire and a total of 360 usable responses were obtained using simple random sampling technique. Findings revealed that, pay satisfaction has the influence or impact on the financial stress. Especially in the pay satisfaction dimensions, financial stress is negatively influenced by pay level and benefits as expected. In contrast, financial stress is positively influenced by the pay raises. Further, dependent variable as financial stress is not influenced significantly by the pay structure and administration. Researchers suggested that, Ministry of Education should come up with proper policy draft regarding to the pay structure and administration. Meantime, Government should conduct the continuous survey among school teachers in terms of financial, occupational stress, work related satisfaction and also performance evaluation. This study would hopefully benefit to the policy makers, and practitioners of Sri Lanka as well as other countries. Key Words: Financial Stress, Pay satisfaction, Northern Province, Sri Lanka and School Teachers

    Enabling Multichannel Participation Through ICT Adaptation

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    Online deliberation invests significant sums in priorities co-decided by inhabitants, and is mostly relegated to small and non-influential experiments. There is a gap between ICT solutions and participatory initiatives. E-participation is a broad, undefined space of opportunities that needs to be operationalized to prove if the many theoretical exercises emphasizing on the potential of ICT in increasing deliberative quality of participatory processes and security, are realistic or not. The EMPATIA platform seeks to radically enhance inclusiveness and impact of participatory budgeting processes in increasing multichannel citizen participation by designing, evaluating and making publicly available an advanced ICT platform for participatory budgeting. EMPATIA takes advantage of the fact that it surrounds an established and widespread social practice with clear and adaptable principles recognized worldwide, alongside a community of practitioners and researchers, and ICT tools, which only need to be adapted, refined and integrated into an adequate PB platform

    Disruptive Technologies in Agricultural Operations: A Systematic Review of AI-driven AgriTech Research

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    YesThe evolving field of disruptive technologies has recently gained significant interest in various industries, including agriculture. The fourth industrial revolution has reshaped the context of Agricultural Technology (AgriTech) with applications of Artificial Intelligence (AI) and a strong focus on data-driven analytical techniques. Motivated by the advances in AgriTech for agrarian operations, the study presents a state-of-the-art review of the research advances which are, evolving in a fast pace over the last decades (due to the disruptive potential of the technological context). Following a systematic literature approach, we develop a categorisation of the various types of AgriTech, as well as the associated AI-driven techniques which form the continuously shifting definition of AgriTech. The contribution primarily draws on the conceptualisation and awareness about AI-driven AgriTech context relevant to the agricultural operations for smart, efficient, and sustainable farming. The study provides a single normative reference for the definition, context and future directions of the field for further research towards the operational context of AgriTech. Our findings indicate that AgriTech research and the disruptive potential of AI in the agricultural sector are still in infancy in Operations Research. Through the systematic review, we also intend to inform a wide range of agricultural stakeholders (farmers, agripreneurs, scholars and practitioners) and to provide research agenda for a growing field with multiple potentialities for the future of the agricultural operations

    Millennial Chinese Consumers’ Perceived Destination Brand Value

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    There has been a substantial rise in the number of Chinese tourists, with the Chinese millennials being important influencers. Yet very little is known about their tourism behavior, particularly how their perceived destination brand values influence their destination loyalty. This study brings in the consumers’ perceived brand value concept from the branding literature to investigate Chinese millennial tourists’ destination loyalty. An online survey was adopted to collect data from 287 Chinese millennial tourists. The findings offer insight into the relative effects of five dimensions of tourists’ perceived destination brand values on their destination loyalty. The findings also extend existing tourism literature, showing the moderating effects of destination brand globality, destination status (domestic vs. international) and national brand attitude on the said relationships. Managerial implications to better target Chinese millennials are discussed together with future research directions

    'Preconditioning' with Low Dose Lipopolysaccharide Aggravates the Organ Injury/Dysfunction Caused by Hemorrhagic Shock in Rats

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    This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedRS is supported by the Program Science without Borders, CAPES Foundation, Ministry of Education of Brazil, Brasilia/DF, Brazil; NSAP is, in part, supported by the Bart’s and The London Charity (753/1722). The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme (FP7/2007-2013) under REA grant agreement no 608765, from the William Harvey Research Foundation and University of Turin (Ricerca Locale ex-60%). This work contributes to the Organ Protection research theme of the Barts Centre for Trauma Sciences, supported by the Barts and The London Charity (Award 753/1722
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