30,340 research outputs found

    Cusp Disruption in Minor Mergers

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    We present 0.55 x 10^6 particle simulations of the accretion of high-density dwarf galaxies by low-density giant galaxies, using models that contain both power-law central density cusps and point masses representing supermassive black holes. The cusp of the dwarf galaxy is disrupted during the merger, producing a remnant with a central density that is only slightly higher than that of the giant galaxy initially. Removing the black hole from the giant galaxy allows the dwarf galaxy to remain intact and leads to a remnant with a high central density, contrary to what is observed. Our results support the hypothesis that the persistence of low-density cores in giant galaxies is a consequence of supermassive black holes.Comment: 5 pages, 2 postscript figures, uses emulateapj.sty. Accepted for publication in The Astrophysical Journal Letter

    A symmetric quantum calculus

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    We introduce the α,β\alpha,\beta-symmetric difference derivative and the α,β\alpha,\beta-symmetric N\"orlund sum. The associated symmetric quantum calculus is developed, which can be seen as a generalization of the forward and backward hh-calculus.Comment: Submitted 26/Sept/2011; accepted in revised form 28/Dec/2011; to Proceedings of International Conference on Differential & Difference Equations and Applications, in honour of Professor Ravi P. Agarwal, to be published by Springer in the series Proceedings in Mathematics (PROM

    Stern-Gerlach Entanglement in Spinor Bose-Einstein Condensates

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    Entanglement of spin and position variables produced by spatially inhomogeneous magnetic fields of Stern-Gerlach type acting on spinor Bose-Einstein condensates may lead to interference effects at the level of one-boson densities. A model is worked out for these effects which is amenable to analytical calculation for gaussian shaped condensates. The resulting interference effects are sensitive to the spin polarization properties of the condensate.Comment: 9 pages, 2 figure

    ESG maturity: A software framework for the challenges of ESG data in investment

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    Given the rising demand for more transparent, consistent, and comprehensive non-financial information in investment, there is a need to provide more reliable, meaningful, and measurable ESG metrics, in a way that most frameworks cannot. Most established frameworks face difficulties and challenges in providing sustainability information to investors in a significant way, lacking in areas such as transparency, reliability, consistency, materiality, and particularly, their focus on the “S” dimension of ESG. The present article purposes to review the challenges associated with several frameworks and to present a solution to overcome them, by giving an overview of a new and innovative software as a service framework, ESG Maturity. This software presents itself as a solution for both reporting companies and their respective investors, by providing both with an assessment of the ESG maturity index of the companies, and delivering a report containing relevant initiatives, strategies, and action plans tailored to each one of them, within different sectors, dimensions, and geographic areas and consequently, their financial and non-financial implementation impact. ESG Maturity is considered a possible answer to the challenges in ESG reporting, having the potential to revolutionize the way companies report their non-financial information and how investors receive it.info:eu-repo/semantics/publishedVersio

    Mudanças morfológicas nas células de Sertoli durante o ciclo reprodutivo de machos do teleósteo Piaractus mesopotamicus (Holmberg, 1887)

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    An investigation of the histological and ultrastructural changes of Sertoli cells during the male reproductive cycle in Piaractus mesopotamicus was made. The results showed that the Sertoli cell development is closely related with germ cell maturation. Therefore, these cells may have some role in germ cell maturation during the reproductive cycle of this species, whether in forming a tissue framework for the developing spermatogenic cysts, aiding in testes reorganization for a new reproductive cycle, in addition to other possible functions discussed in the text.Realizou-se uma investigação das mudanças histológicas e ultra-estruturais das células de Sertoli durante o ciclo reprodutivo de machos de Piaractus mesopotamicus. Os resultados mostraram que o desenvolvimento das células de Sertoli está estritamente relacionado à maturação das células gaméticas. Portanto, as células de Sertoli têm algum papel na maturação das células germinativas durante o ciclo reprodutivo dessa espécie, talvez formando um tecido de sustentação para os cistos espermatogênicos em desenvolvimento, ajudando a reorganização testicular para um novo ciclo reprodutivo, além de outras possíveis funções discutidas no texto.24124
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