13,381 research outputs found

    Canonical treatment of two dimensional gravity as an anomalous gauge theory

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    The extended phase space method of Batalin, Fradkin and Vilkovisky is applied to formulate two dimensional gravity in a general class of gauges. A BRST formulation of the light-cone gauge is presented to reveal the relationship between the BRST symmetry and the origin of SL(2,R)SL(2,R) current algebra. From the same principle we derive the conformal gauge action suggested by David, Distler and Kawai.Comment: 11 pages, KANAZAWA-92-1

    Structure of air shower disc near the core

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    The longitudinal structure of the air shower disk is studied by measuring the arrival time distributions of air shower particles for showers with electron size in the range 3.2 x 10 to the 5.5. power to 3.2 x 10 to the 7.5 power in the Akeno air-shower array (930 gcm squared atmospheric depth). The average FWHM as a parameter of thickness of air shower disk increases with core distances at less than 50m. AT the present stage, dependence on electron size, zenith angle and air shower age is not apparent. The average thickness of the air shower disk within a core distance of 50m could be determined by an electromagnetic cascade starting from the lower altitude

    Lateral distribution of electrons of air showers

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    The lateral distribution of electrons (LDE) of the air showers of size 10 to the 5th power to 10 to the 6th power was studied within one MU. It was found that the LDE of the air showers observed is well represented by NKG function except for vicinity of the core. It was also found that LDE measured by thin scintillators does not differ from that measured by thick ones of 50mm thickness

    Absence of contagious yawning in children with autism spectrum disorder

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    This study is the first to report the disturbance of contagious yawning in individuals with autism spectrum disorder (ASD). Twenty-four children with ASD as well as 25 age-matched typically developing (TD) children observed video clips of either yawning or control mouth movements. Yawning video clips elicited more yawns in TD children than in children with ASD, but the frequency of yawns did not differ between groups when they observed control video clips. Moreover, TD children yawned more during or after the yawn video clips than the control video clips, but the type of video clips did not affect the amount of yawning in children with ASD. Current results suggest that contagious yawning is impaired in ASD, which may relate to their impairment in empathy. It supports the claim that contagious yawning is based on the capacity for empathy

    Transition effect of air shower particles in plastic scintillators

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    The transition effect of air shower particles in the plastic scintillators near the core was measured by scintillators of various thickness. The air showers selected for the measurement were of 10,000. Results obtained are as follows: (1) the multiplication of shower particles in the scintillators is less than 20% for that of 50 mm thickness; (2) dependence of the transition effect on age parameter is not recognized within the experimental errors

    Character of energy flow in air shower core

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    Energy per charged particle near the core of air showers was measured by 9 energy flow detectors, which were the combination of Cerenkov counters and scintillators. Energy per particle of each detector was normalized to energy at 2m from the core. The following results were obtained as to the energy flow: (1) integral frequency distribution of mean energy per particle (averaged over 9 detectors) is composed of two groups separated distinctly; and (2) showers contained in one group show an anisotropy of arrival direction

    X-ray and Radio Follow-up Observations of High-Redshift Blazar Candidates in the Fermi-LAT Unassociated Source Population

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    We report on the results of X-ray and radio follow-up observations of two GeV gamma-ray sources 2FGL J0923.5+1508 and 2FGL J1502.1+5548, selected as candidates for high-redshift blazars from unassociated sources in the {\it Fermi} Large Area Telescope Second Source Catalog. We utilize the Suzaku satellite and the VLBI Exploration of Radio Astrometry (VERA) telescopes for X-ray and radio observations, respectively. For 2FGL J0923.5+1508, a possible radio counterpart NVSS J092357+150518 is found at 1.4 GHz from an existing catalog, but we do not detect any X-ray emission from it and derive a flux upper limit F2−8keV<F_{\rm 2-8 keV} < 1.37 ×\times 10−14^{-14} erg cm−2^{-2} s−1^{-1}. Radio observations at 6.7 GHz also result in an upper limit of S6.7GHzS_{\rm 6.7 GHz} << 19 mJy, implying a steep radio spectrum that is not expected for a blazar. On the other hand, we detect X-rays from NVSS J150229+555204, the potential 1.4 GHz radio counterpart of 2FGL J1502.1+5548. The X-ray spectrum can be fitted with an absorbed power-law model with a photon index γ\gamma=1.8−0.2+0.3^{+0.3}_{-0.2} and the unabsorbed flux is F2−8keVF_{\rm 2-8 keV}=4.3−1.0+1.1^{+1.1}_{-1.0} ×\times 10−14^{-14} erg cm−2^{-2} s−1^{-1}. Moreover, we detect unresolved radio emission at 6.7 GHz with flux S6.7GHzS_{\rm 6.7 GHz}=30.1 mJy, indicating a compact, flat-spectrum radio source. If NVSS J150229+555204 is indeed associated with 2FGL J1502.1+5548, we find that its multiwavelength spectrum is consistent with a blazar at redshift z∼3−4z \sim 3-4.Comment: 24 pages, 7 figures, 6 tables, accepted for publication in Ap
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