17,802 research outputs found

    The Large Magellanic Cloud: A power spectral analysis of Spitzer images

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    We present a power spectral analysis of Spitzer images of the Large Magellanic Cloud. The power spectra of the FIR emission show two different power laws. At larger scales (kpc) the slope is ~ -1.6, while at smaller ones (tens to few hundreds of parsecs) the slope is steeper, with a value ~ -2.9. The break occurs at a scale around 100-200 pc. We interpret this break as the scale height of the dust disk of the LMC. We perform high resolution simulations with and without stellar feedback. Our AMR hydrodynamic simulations of model galaxies using the LMC mass and rotation curve, confirm that they have similar two-component power-laws for projected density and that the break does indeed occur at the disk thickness. Power spectral analysis of velocities betrays a single power law for in-plane components. The vertical component of the velocity shows a flat behavior for large structures and a power law similar to the in-plane velocities at small scales. The motions are highly anisotropic at large scales, with in-plane velocities being much more important than vertical ones. In contrast, at small scales, the motions become more isotropic.Comment: 8 pages, 4 figures, talk presented at "Galaxies and their Masks", celebrating Ken Freeman's 70-th birthday, Sossusvlei, Namibia, April 2010. To be published by Springer, New York, editors D.L. Block, K.C. Freeman, & I. Puerar

    Anopheline fauna of parts of Tirap district, Arunachal Pradesh with reference to malaria transmission

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    In a survey on the anopheline fauna in highly malaria endemic areas of the Tirap district of Arunachal Pradesh, 7476 anophelines belonging to 17 species were collected, including seven species of anophelines which are recognized malaria vectors in India. Anopheles tessellatus and A. jamesii were recorded for the first time in this area. The parasitological survey revealed that the area was endemic for malaria particularly P. falciparum. the slide positivity rate and slide falciparum rate being 25.63 and 19.21 per cent respectively. On dissection of 10 anopheies species, malarial infection was detected in two viz., A. minimus and A. dirus

    Signature of strong atom-cavity interaction on critical coupling

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    We study a critically coupled cavity doped with resonant atoms with metamaterial slabs as mirrors. We show how resonant atom-cavity interaction can lead to a splitting of the critical coupling dip. The results are explained in terms of the frequency and lifetime splitting of the coupled system.Comment: 8 pages, 5 figure

    The potential link between corporate innovations and corporate competitiveness:Evidence from IT firms in the UK

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    Purpose: The purpose of this paper is to provide a thorough empirical investigation of the potential link between corporate innovations and corporate competitiveness in the context of the UK IT industry. Design/methodology/approach: This research uses a panel of 216 UK IT firms for the period from 2000 to 2016. The sample data for this study were extracted from the Worldscope, extracted from the Datastream database from Thomson Reuters. For the analysis of the data, the generalised method of moments model is applied. Findings: The results of this study provide empirical evidence that there exists a strong, positive link between corporate innovations and corporate competitiveness. Such evidence further reinforces the common view in the current literature of strategic management that because of the nature of their business, firms in the IT industry need to enhance their innovative capacities on a continual basis because of their critical role on these firms’ success and survival. Also, it is found that when the proxies for corporate innovations are lagged by two periods, their impact on corporate competitiveness becomes relatively more significant. However, when they are further lagged, i.e. by three periods, such an impact turns out to be relatively less pronounced. Research limitations/implications: The data gathered for this paper was restricted to IT-oriented firms in the UK. Using a secondary database (Datastream), the paper considered the period of 2000-2016. Originality/value: The research makes a significant contribution to the current debate on the relationship between information technology, innovation and performance, referred to in the literature as the productivity paradox, by studying the problem in the IT industry. It supports organisations from the sector in their efforts to deal with the dynamic nature of technological innovations and of the context where they operate. Methodologically, the way the study has measured the concepts of innovation and performance and the lessons learned from their analysis has also brought value to the research

    Aspects of Horava-Lifshitz cosmology

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    We review some general aspects of Horava-Lifshitz cosmology. Formulating it in its basic version, we extract the cosmological equations and we use observational data in order to constrain the parameters of the theory. Through a phase-space analysis we extract the late-time stable solutions, and we show that eternal expansion, and bouncing and cyclic behavior can arise naturally. Concerning the effective dark energy sector we show that it can describe the phantom phase without the use of a phantom field. However, performing a detailed perturbation analysis, we see that Horava-Lifshitz gravity in its basic version suffers from instabilities. Therefore, suitable generalizations are required in order for this novel theory to be a candidate for the description of nature.Comment: 10 pages, 4 figures, invited talk given at the 2nd International Workshop on Dark Matter, Dark Energy and Matter-Antimatter Assymetry, National Tsing Hua University, Hsinchu, Taiwan, November 5-6, 201

    Low Power Superconducting Microwave Applications and Microwave Microscopy

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    We briefly review some non-accelerator high-frequency applications of superconductors. These include the use of high-Tc superconductors in front-end band-pass filters in cellular telephone base stations, the High Temperature Superconductor Space Experiment, and high-speed digital electronics. We also present an overview of our work on a novel form of near-field scanning microscopy at microwave frequencies. This form of microscopy can be used to investigate the microwave properties of metals and dielectrics on length scales as small as 1 mm. With this microscope we have demonstrated quantitative imaging of sheet resistance and topography at microwave frequencies. An examination of the local microwave response of the surface of a heat-treated bulk Nb sample is also presented.Comment: 11 pages, including 6 figures. Presented at the Eight Workshop on RF Superconductivity. To appear in Particle Accelerator
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