847 research outputs found

    Natural Theories of Ultra-Low Mass PNGB's: Axions and Quintessence

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    We consider the Wilson Line PNGB which arises in a U(1)^N gauge theory, abstracted from a latticized, periodically compactified extra dimension U(1). Planck scale breaking of the PNGB's global symmetry is suppressed, providing natural candidates for the axion and quintessence. We construct an explicit model in which the axion may be viewed as the 5th component of the U(1)_Y gauge field in a 1+4 latticized periodically compactified extra dimension. We also construct a quintessence PNGB model where the ultra-low mass arises from Planck-scale suppressed physics itself.Comment: 20 pages, fixed typo and reference

    Performance Analysis of Dual Unipolar/Bipolar Spectral Code in Optical CDMA Systems

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    This study analyzes and calculates dual unipolar and bipolar coded configurations of spectral-amplitude-coding opticalcode division multiple access (SAC-OCDMA) systems by using simulation methods. The important feature of theSAC-OCDMA systems is that multiple access interference (MAI) can be eliminated by code sequences of a fixed inphasecross-correlation value. This property can be effectively canceled multiple access interference by using balancedetection schemes. This study uses Walsh-Hadamard codes as signature codes for the unipolar and bipolar schemes.The coder and decoder structures are based on optical filters of fiber Bragg gratings (FBGs). The simulation results ofunipolar/bipolar coding structures are first presented by commercial simulation obtained using OptiSystem software.The simulation results show that the bit error rate (BER) through use of the bipolar coding method is superior to theunipolar scheme, especially when the received effect power is large. When the system needs good performance totransmit multimedia data, we can use bipolar scheme in the network. If the users only transmit voice data, the unipolarmethod can be employed. The eye diagram also shows that the bipolar encoding structure exhibits a wider openingthan the unipolar encoding structure. The flexible implementation of codewords assigns and integratable hardwaredesigns for the scheme with FBGs to realize dual coding OCDMA system is proposed

    Scheduling jobs with agreeable processing times and due dates on a single batch processing machine

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    AbstractIn this paper we study the problems of scheduling jobs with agreeable processing times and due dates on a single batch processing machine to minimize total tardiness, and weighted number of tardy jobs. We prove that the problem of minimizing total tardiness is NP-hard even if the machine capacity is two jobs and we develop a pseudo-polynomial-time algorithm for an NP-hard special case of this problem. We also develop a pseudo-polynomial-time algorithm for the NP-hard problem of minimizing weighted number of tardy jobs, which suggests that this problem cannot be strongly NP-hard unless P=NP

    Fractal Theory Space: Spacetime of Noninteger Dimensionality

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    We construct matter field theories in ``theory space'' that are fractal, and invariant under geometrical renormalization group (RG) transformations. We treat in detail complex scalars, and discuss issues related to fermions, chirality, and Yang-Mills gauge fields. In the continuum limit these models describe physics in a noninteger spatial dimension which appears above a RG invariant ``compactification scale,'' M. The energy distribution of KK modes above M is controlled by an exponent in a scaling relation of the vacuum energy (Coleman-Weinberg potential), and corresponds to the dimensionality. For truncated-s-simplex lattices with coordination number s the spacetime dimensionality is 1+(3+2ln(s)/ln(s+2)). The computations in theory space involve subtleties, owing to the 1+3 kinetic terms, yet the resulting dimensionalites are equivalent to thermal spin systems. Physical implications are discussed.Comment: 28 pages, 6 figures; Paper has been amplified with a more detailed discussion of a number of technical issue

    Particle dynamics in chirped-frequency fluctations

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    The Price of Anarchy for Selfish Ring Routing is Two

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    We analyze the network congestion game with atomic players, asymmetric strategies, and the maximum latency among all players as social cost. This important social cost function is much less understood than the average latency. We show that the price of anarchy is at most two, when the network is a ring and the link latencies are linear. Our bound is tight. This is the first sharp bound for the maximum latency objective.Comment: Full version of WINE 2012 paper, 24 page

    Revisiting donkey anaphora in Mandarin Chinese: A reply to Pan and Jiang (2015)

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    Theoretical and Experimental Linguistic

    Tissue-dependent developmental expression of a cytosolic thyroid hormone protein gene in Xenopus: Its role in the regulation of amphibian metamorphosis

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    AbstractWe have cloned the cDNA encoding the Xenopus laevis homolog of mammalian cytosolic thyroid hormone binding protein (CTHBP). We found that while its mRNA level varies little in whole animals during development, the expression of CTHBP is inversely correlated with tissue-specific transformations during metamorphosis. A high level of its mRNA was observed in the tail of premetamorphic tadpoles. However, the expression is dramatically repressed with the onset of rapid tail resorption. In the hindlimb, the expression of CTHBP is very low during morphogenesis. Subsequently, its expression continuously increases during the period of limb growth. In contrast, a low level of CTHBP expression was detected in the intestine throughout metamorphosis. These results suggest that CTHBP could function to modulate the metamorphic process by regulating the level of intracellular thyroid hormones

    Localized Fermions and Anomaly Inflow via Deconstruction

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    We study fermion localization in gauge theory space. We consider four dimensional product gauge groups in which light chiral fermions transform under different gauge factors of the product group. This construction provides a suppression of higher dimensional operators. For example, it can be used to suppress dangerous proton decay operators. The anomalies associated with the light chiral fermions are compensated by Wess-Zumino terms, which in the continuum limit reproduce the five dimensional Chern-Simons term.Comment: 12 pages, minor changes to section
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