1,742,222 research outputs found
[Southern Pacific, No. 1232]
No full textSouthern Pacific Locomotive 1232 sits in a rail yard in front of an Edwards Coffee plant.Negative sleeve: [handwritten] Southern Pacific 1232
Δ(1232)-Resonance in the Hydrogen Spectrum
Full text linkThe electromagnetic excitation of the Δ(1232)-resonance plays an appreciable role in the Lamb shift and hyperfine structure of muonic and electronic hydrogen. Its effect appears at the subleading order O(α5), together with other proton-polarizability contributions from forward two-photon exchange. We use the large-Nc relations for the nucleon-to-delta transition form factors to compute the effect of the Δ(1232) in the hydrogen spectrum. We pay particular attention to a subtile difference between predictions based on a direct calculation of the two-photon exchange (or Compton scattering amplitudes) (Faustov et al. in Phys At Nucl 62:2099, 1999) and predictions based on the Δ(1232)-production photoabsorption cross sections (Buchmann in Can J Phys 87:773–783, 2009). The mismatch is explained by studying the dispersion relations for tree-level Compton scattering off the proton in more details
Ley 1232 de 2008
No full textLey 1232 de julio 17 de 2008, por la cual se modifica la Ley 82 de 1993, Ley Mujer Cabeza de Familia y se dictan otras disposiciones
Optical identification of IGR J18308-1232 as a cataclysmic variable
Full text linkWe report on a spectroscopic analysis of optical sources inside the error circle of the XMM-Newton slew source XMMLS1 J183049.6-123218 (see Ibarra et al., ATel #1527), associated with the unidentifiedINTEGRAL source IGR J18308-1232 (Bird et al. 2007, ApJS, 170, 175). The observations were performed on 2008 June 28, starting at 06:37 UT, with the Boller & Chivens spectrograph mounted on the 2.1m telescope of the Observatorio Astronomico Nacional (San Pedro Martir, Baja California, Mèxico), for a total exposure time of 7200 s. We found that the optical spectrum of source USNO-A2.0 0750-13371563 (with coordinates RA =18 30 49.88, DEC = -12 32 18.7 and magnitude R ~ 17.0) shows a red continuum, possibly absorbed by the Galactic dust along the line of sight; superimposed on this continuum several Balmer, HeI and HeII narrow emission lines at a redshift consistent with zero are apparent. The Halpha emission is detected with an EW ~ 22 Angstrom. This spectrum resembles that of a Cataclysmic Variable (similar to those reported in e.g. Masetti et al. 2006, A&A, 459, 21 and in Masetti et al. 2008, A&A, 482, 113), and the relative strength of the HeII 4686 Angstrom emission suggests the presence of a magnetic white dwarf in this system. Thus we identify the object USNO-A2.0 0750-13371563 as the optical counterpart of the hard X-ray source IGR J18308-1232, and as a new, possibly magnetic, Cataclysmic Variable
О величине экспериментального значения массы ∆⁺ (1232) резонанса из реакций γp→nπ⁺ (pπ⁰)
No full textThe reliability of the phenomenological estimates for the D⁺(1232) mass is questioned coming from the of π⁺ and π⁰ mesons photoproduction data off proton target till the end of 2001. The origin of an old discrepancy for the D⁺(1232) mass presented in tables of the Particle Data Group is discussed.The author would like to thank I.I. Strakovsky for kindly sending the information about article [14]
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
О величине экспериментального значения массы ∆⁺ (1232) резонанса из реакций γp→nπ⁺ (pπ⁰)
Full text linkThe reliability of the phenomenological estimates for the D⁺(1232) mass is questioned coming from the of π⁺ and π⁰ mesons photoproduction data off proton target till the end of 2001. The origin of an old discrepancy for the D⁺(1232) mass presented in tables of the Particle Data Group is discussed.The author would like to thank I.I. Strakovsky for kindly sending the information about article [14]
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