2,653,367 research outputs found

    Background effects on reconstructed WIMP couplings

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    In this talk, I presented effects of small, but non-negligible unrejected background events on the determinations of WIMP couplings/cross sections.Comment: 4 pages, 5 eps figures, to appear in the proceedings of the 12th International Conference on Topics in Astroparticle and Underground Physics (TAUP 2011), September 5-9, 2011, Munich, German

    Ant-Colony-Based Multiuser Detection for MC DS-CDMA Systems

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    In this contribution we present a novel ant colony optimization (ACO) based multi-user detector (MUD) designed for synchronous multi-carrier direct sequence code division multiple access (MC DSCDMA) systems. The operation of the ACO-based MUD is based on the behaviour of the ant colony in nature. The ACO-based MUD aims for achieving the same bit-error-rate (BER) performance as the optimum maximum likelihood (ML) MUD, without carrying out an exhaustive search of the entire MC DS-CDMA search space constituted by all possible combinations of the received multi-user vectors. We will demonstrate that the system is capable of supporting almost as many users as the number of chips in the spreading sequence, while searching only a small fraction of the entire ML search space. It will also be demonstrated that the number of floating point operations per second is a factor of 108 lower for the proposed ACO-based MUD than that of the ML MUD, when supporting K = 32 users in a MC DS-CDMA system employing 31-chip Gold codes as the T-domain spreading sequence

    Resource consents - intangible fixed assets? Yes, but, too difficult by far!

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    Recent international attempts to draft an accounting standard (IAS38) which establishes the most widely acceptable treatment for intangible assets have sparked debate among standard setters, practising accountants and media analysts. Contentious issues include differing treatment for internally and externally generated intangible fixed assets, and the requirement for the existence of a ready market for the exchange of intangible assets. A further question has been identified, that of whether the ‘right to do something’, as in permission to act, is in itself an intangible asset and if so how should it be treated. An example of this is resource consents issued under the Resource Management Act 1991. The aim of this research was to investigate the nature of resource consents as intangible assets according to ICANZ disclosure and recognition standards and to determine the level of disclosure practised by companies listed on the New Zealand Stock Exchange. Disclosure of resource consent details as non-financial information would provide a significant proportion of the benefits involved in disclosing this class of asset while limiting the costs involved in the production of the information. We conclude that the details of resource consents held should be disclosed in the annual report as additional non-financial information, or as a separate schedule of resource consents held in the notes to the financial statements as per FRS1. This view is not addressed by the requirements of IAS38 or ED87 as this 'class of intangible assets' is not discussed at all. However, it can be argued that the omission of resource consents and other similar intangibles is contrary to the spirit of the true and fair view requirement of the Financial Reporting Act and Generally Accepted Accounting Principles (GAAP)

    Exposing the dressed quark's mass

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    This snapshot of recent progress in hadron physics made in connection with QCD's Dyson-Schwinger equations includes: a perspective on confinement and dynamical chiral symmetry breaking (DCSB); a pre'cis on the physics of in-hadron condensates; results on the hadron spectrum, including dressed-quark-core masses for the nucleon and Delta, their first radial excitations, and the parity-partners of these states; an illustration of the impact of DCSB on the electromagnetic pion form factor, thereby exemplifying how data can be used to chart the momentum-dependence of the dressed-quark mass function; and a prediction that F_1^{p,d}/F_1^{p,u} passes through zero at Q^2\approx 5m_N^2 owing to the presence of nonpointlike scalar and axial-vector diquark correlations in the nucleon.Comment: 10 pages, 4 figures, 2 tables. Contribution to the Proceedings of the 4th Workshop on Exclusive Reactions at High Momentum Transfer, Thomas Jefferson National Accelerator Facility Newport News, Virginia, 18-21 May 201

    Atomic Radiative Transitions in Thermo Field Dynamics

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    In this work we rederive the Lamb-Retherford energy shift for an atomic electron in the presence of a thermal radiation. Using the Dalibard, Dupont-Roc and Cohen-Tannoudji (DDC) formalism, where physical observables are expressed as convolutions of suitable statistical functions, we construct the electromagnetic field propagator of Thermo Field Dynamics in the Coulomb gauge in order to investigate finite temperature effects on the atomic energy levels. In the same context, we also analyze the problem of the ground state stability.Comment: LaTex file, 13 pages, no figures, includes PACS numbers and minor changes in the text where a new section has been adde

    Introduction to Nuclear Propulsion: Lecture 15 - Nuclear Test Operations

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    The test operation of nuclear power plants, specifically nuclear rockets, bears some interesting similarities to the operation of chemical rocket tests as well as, of course, many differences. A significant feature common to both nuclear and chemical rocket tests is that all the fuel for the entire operation is loaded at the start of the test. As a direct consequence of this fact, the operation of nuclear power plants must be surrounded with adequate safety precautions, as is indeed the case in the operation of chemical rockets, A second direct consequence is that in both types of testing a very thorough and complete checkout is made before starting the test

    Complementary monostable circuits achieve low power drain and high reliability

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    Two-transistor multivibrator has minimum power dissipation and maximum reliability. It minimizes the use of components that are subject to environmental changes or other unpredictable behavior
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