6,389 research outputs found

    DarkHistory: A code package for calculating modified cosmic ionization and thermal histories with dark matter and other exotic energy injections

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    We present a new public Python package, DarkHistory, for computing the effects of dark matter annihilation and decay on the temperature and ionization history of the early universe. DarkHistory simultaneously solves for the evolution of the free electron fraction and gas temperature, and for the cooling of annihilation/decay products and the secondary particles produced in the process. Consequently, we can self-consistently include the effects of both astrophysical and exotic sources of heating and ionization, and automatically take into account backreaction, where modifications to the ionization/temperature history in turn modify the energy-loss processes for injected particles. We present a number of worked examples, demonstrating how to use the code in a range of different configurations, in particular for arbitrary dark matter masses and annihilation/decay final states. Possible applications of DarkHistory include mapping out the effects of dark matter annihilation/decay on the global 21cm signal and the epoch of reionization, as well as the effects of exotic energy injections other than dark matter annihilation/decay. The code is available at https://github.com/hongwanliu/DarkHistory with documentation at https://darkhistory.readthedocs.io . Data files required to run the code can be downloaded at https://doi.org/10.7910/DVN/DUOUWA .Comment: 40 pages, 17 figure

    Heavy Dark Matter Annihilation from Effective Field Theory

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    We formulate an effective field theory description for SU(2)L_L triplet fermionic dark matter by combining nonrelativistic dark matter with gauge bosons in the soft-collinear effective theory. For a given dark matter mass, the annihilation cross section to line photons is obtained with 5% precision by simultaneously including Sommerfeld enhancement and the resummation of electroweak Sudakov logarithms at next-to-next-to-leading logarithmic order. Using these results, we present more accurate and precise predictions for the gamma-ray line signal from annihilation, updating both existing constraints and the reach of future experiments.Comment: 5 pages, 2 figure

    Labor Dispute Disqualification Under the Ohio Unemployment Compensation Act

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    Institutional accreditation liaisons in the Southern Association of Colleges and Schools region: characteristics, responsibilities, and force field analysis

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    The purpose of this study was to explore the Southern Association of Colleges and Schools Commission on Colleges’ role of Accreditation Liaison to (a) explore the characteristics of the professionals who fill the Accreditation Liaison role and (b) understand factors that support or challenge liaisons. Within the theoretical framework of Kurt Lewin’s Field Theory, a sequential mixed-methods research design was employed to collect data in two phases. The quantitative method in the first phase was an on-line survey. The instrument focused on respondents’ educational, professional, and demographic characteristics, as well as their roles, responsibilities, and practices as Accreditation Liaisons. The second, qualitative, phase of the study relied on telephone interviews for data collection. Confidential interviews served to clarify survey responses, as needed, and to collect data regarding the factors that drive/support or block/challenge respondents in their roles as Accreditation Liaisons. Research findings are presented for both phases of the study, followed by meta-inferences, recommendations for future research, and considerations for higher education professionals whose work focuses on accreditation

    Mini-Conference on Hamiltonian and Lagrangian Methods in Fluid and Plasma Physics

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    A mini-conference on Hamiltonian and Lagrangian methods in fluid and plasma physics was held on November 14, 2002, as part of the 44th meeting of the Division of Plasma Physics of the American Physical Society. This paper summarizes the material presented during the talks scheduled during the Mini-Conference, which was held to honor Allan Kaufman on the occasion of his 75th birthday.Comment: 14 pages, conference summar

    Textpresso for Neuroscience: Searching the Full Text of Thousands of Neuroscience Research Papers

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    Textpresso is a text-mining system for scientific literature. Its two major features are access to the full text of research papers and the development and use of categories of biological concepts as well as categories that describe or relate objects. A search engine enables the user to search for one or a combination of these categories and/or keywords within an entire literature. Here we describe Textpresso for Neuroscience, part of the core Neuroscience Information Framework (NIF). The Textpresso site currently consists of 67,500 full text papers and 131,300 abstracts. We show that using categories in literature can make a pure keyword query more refined and meaningful. We also show how semantic queries can be formulated with categories only. We explain the build and content of the database and describe the main features of the web pages and the advanced search options. We also give detailed illustrations of the web service developed to provide programmatic access to Textpresso. This web service is used by the NIF interface to access Textpresso. The standalone website of Textpresso for Neuroscience can be accessed at http://www.textpresso.org/neuroscience

    Concentration of norms and eigenvalues of random matrices

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    We prove concentration results for â„“pn\ell_p^n operator norms of rectangular random matrices and eigenvalues of self-adjoint random matrices. The random matrices we consider have bounded entries which are independent, up to a possible self-adjointness constraint. Our results are based on an isoperimetric inequality for product spaces due to Talagrand.Comment: 15 pages; AMS-LaTeX; updated one referenc
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