5,304 research outputs found

    Economics and ecology

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    Evaluating Disparities in Quality of Life in the City of Atlanta Using an Urban Health Index

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    Measuring disparities in Quality of Life (QOL) can be challenging due to the vast amount of factors to be included. This study attempts to measure disparities in QOL using a newly developed Urban Health Index (UHI). Using 128 census tracts in City of Atlanta in Georgia as an example, this study selects six variables that are related to QOL. Their geometric mean is then used to construct a single numeric value for each census tract. The QOL disparity ratio is then determined by the upper and lower 10% of the data. The slope of disparity is calculated using the remaining 80% of the data. The results show that urban health index may be an affective indicator of QOL in a city

    Tunable pinning in superconducting films with magnetic micro-loops

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    We study the flux pinning properties of superconductor/magnetic micro-rings lattice hybrid structures. The used open triangular micromagnets represent an eight-fold degree of freedom system, with six polarized and two flux-closure possible states. By conveniently choosing the magnetic state of the underlying rings it is possible to induce different pinning potentials. We show that the magnetic vortex state with minimum stray field produces a weaker pinning in comparison with the polarized states

    Topological quantization of energy transport in micro- and nano-mechanical lattices

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    Topological effects typically discussed in the context of quantum physics are emerging as one of the central paradigms of physics. Here, we demonstrate the role of topology in energy transport through dimerized micro- and nano-mechanical lattices in the classical regime, i.e., essentially "masses and springs". We show that the thermal conductance factorizes into topological and non-topological components. The former takes on three discrete values and arises due to the appearance of edge modes that prevent good contact between the heat reservoirs and the bulk, giving a length-independent reduction of the conductance. In essence, energy input at the boundary mostly stays there, an effect robust against disorder and nonlinearity. These results bridge two seemingly disconnected disciplines of physics, namely topology and thermal transport, and suggest ways to engineer thermal contacts, opening a direction to explore the ramifications of topological properties on nanoscale technology.Comment: 6 pages, 3 figures; Supplemental information included as an ancillary fil

    Spectral monitoring of AGNs: Preliminary results for Ark 564 and Arp 102B

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    We present preliminary results of the long term spectral monitoring of two active galactic nuclei with different broad line shapes: Ark 564 and Arp 102B. Ark 564 is a bright nearby narrow line Syfert 1 (NLS1) galaxy with relatively narrow permitted optical emission lines and a high FeII/Hβ{\beta} ratio, while Arp 102B is a nearby broad-line radio galaxy with broad double-peaked Balmer emission lines. The spectra of Ark 564 were observed during 11-year period (1999-2009) and the spectra of Arp 102B in the 12-year period (1998-2009), with SAO 6-m and 1-m telescopes (Russia) and the GHAO 2.1-m telescope (Cananea, Mexico).Comment: Presented on "8th Serbian Conference on Spectral Line Shapes in Astrophysics". In revised version minor changes in the tex
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