12,277 research outputs found

    The associative algebras of conformal field theory

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    Modulo the ideal generated by the derivative fields, the normal ordered product of holomorphic fields in two-dimensional conformal field theory yields a commutative and associative algebra. The zero mode algebra can be regarded as a deformation of the latter. Alternatively, it can be described as an associative quotient of the algebra given by a modified normal ordered product. We clarify the relation of these structures to Zhu's product and Zhu's algebra of the mathematical literature.Comment: LaTeX (BibTeX), 6 pages, no figure

    Warranted Diagnosis

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    A diagnostic process is an investigative process that takes a clinical picture as input and outputs a diagnosis. We propose a method for distinguishing diagnoses that are warranted from those that are not, based on the cognitive processes of which they are the outputs. Processes designed and vetted to reliably produce correct diagnoses will output what we shall call ā€˜warranted diagnosesā€™. The latter are diagnoses that should be trusted even if they later turn out to have been wrong. Our work is based on the recently developed Cognitive Process Ontology and further develops the Ontology of General Medical Science. It also has applications in fields such as intelligence, forensics, and predictive maintenance, all of which rely on vetted processes designed to secure the reliability of their outputs

    Municipal Infrastructure Delivery in Ethiopia: A bottomless pit or an option to reach the Millennium Development Goals?

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    The following paper examines the different options to finance local public infrastructure in Ethiopia based on the assumption that the federal government of Ethiopia will not provide any guarantees for local borrowing. Besides a detailed description of the local public finance system and the capital market in Ethiopia, the paper also sets out some international successful practices in municipal infrastructure financing. Based on the observation of the Ethiopian case and the consideration of the international experiences, the paper has two major pillars that very specifically identify actions required for implementation. On the one hand, the paper recommends a number of feasible arrangements to generate a revenue enhancement of the local authorities in the existing intergovernmental framework. On the other hand, the paper suggests a solution - for creditworthy as well as for potentially creditworthy urban local governments (ULG) - to finance their future demand of public infrastructure together with the national finance institutions as well as the international donors.Fiscal Federalism, Grants, Ethiopia, Urban and Rural Economies

    The Comparison of the Swift Gamma-Ray Bursts With and Without Measured Redshifts

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    Gamma-ray bursts, detected by the Swift satellite, are separated into two samples: the bursts with and without determined redshifts. These two samples are compared by the standard Student t-test and F-test. We have compared the dispersions and the mean values of the durations, peak fluxes and fluences in order to find any differences among these two samples. No essential differences were found.Comment: Published in the Proceedings of the 4th Heidelberg International Symposium on High Energy Gamma-Ray Astronomy, 200
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