847 research outputs found
Natural Theories of Ultra-Low Mass PNGB's: Axions and Quintessence
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
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
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
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
The Price of Anarchy for Selfish Ring Routing is Two
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)
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
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
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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