1,798 research outputs found

    Ngrams and Engrams: the use of structural and conceptual features to discriminate between English translations of religious texts

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    In this paper, we present experiments using the Linguistic Inquiry and Word Count (LIWC) program, a ‘closed-class keyword’ (CCK) analysis and a ‘correspondence analysis’ (CA) to examine whether the Scientology texts of L. Ron Hubbard are linguistically and conceptually like those of other religions. A Kruskal–Wallis test comparing the frequencies of LIWC category words in the Scientology texts and the English translations of the texts of five other religions showed that there were eighteen categories for which the Scientology texts differed from the others, and between one and seventeen for the other religions. In the CCK experiment, keywords typical of each religion were found, both by comparing the religious texts with one another and with the Brown corpus of general English. The most typical keywords were looked up in a concordancer and were manually coded with conceptual tags. The set of categories found for the Scientology texts showed little overlap with those found for the others. Our CA experiments produced fairly clear clusters of texts by religion. Scientology texts were seen at one pole on the first factor, with Christian and Islamic texts at the other. It appears that, in several ways, the Scientology texts are dissimilar to the texts of some of the world's major religions

    UV Circular Polarisation in Star Formation Regions : The Origin of Homochirality?

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    Ultraviolet circularly polarised light has been suggested as the initial cause of the homochirality of organic molecules in terrestrial organisms, via enantiomeric selection of prebiotic molecules by asymmetric photolysis. We present a theoretical investigation of mechanisms by which ultraviolet circular polarisation may be produced in star formation regions. In the scenarios considered here, light scattering produces only a small percentage of net circular polarisation at any point in space, due to the forward throwing nature of the phase function in the ultraviolet. By contrast, dichroic extinction can produce a fairly high percentage of net circular polarisation (∌10%) and may therefore play a key role in producing an enantiomeric excessPeer reviewe

    Iron biogeochemistry across marine systems progress from the past decade

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    Based on an international workshop (Gothenburg, 14–16 May 2008), this review article aims to combine interdisciplinary knowledge from coastal and open ocean research on iron biogeochemistry. The major scientific findings of the past decade are structured into sections on natural and artificial iron fertilization, iron inputs into coastal and estuarine systems, colloidal iron and organic matter, and biological processes. Potential effects of global climate change, particularly ocean acidification, on iron biogeochemistry are discussed. The findings are synthesized into recommendations for future research areas

    EMG/ENG services rendered by clinical neurophysiology technologists in solo practice

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    CITATION: Bill, P. L. A., et al. 1998. EMG/ENG services rendered by clinical neurophysiology technologists in solo practice. South African Medical Journal, 88(11):1360.The original publication is available at http://www.samj.org.za[No abstract available]Publisher’s versio

    Infrared spectroscopy of eruptive variable protostars from VVV

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    In a companion work (Paper I), we detected a large population of highly variable Young Stellar Objects (YSOs) in the Vista Variables in the Via Lactea (VVV) survey, typically with class I or flat spectrum spectral energy distributions and diverse light-curve types. Here we present infrared spectra (0.9–2.5??m) of 37 of these variables, many of them observed in a bright state. The spectra confirm that 15/18 sources with eruptive light curves have signatures of a high accretion rate, either showing EXor-like emission features (?v = 2 CO, Br?) and/or FUor-like features (?v = 2 CO and H2O strongly in absorption). Similar features were seen in some long-term periodic YSOs and faders but not in dippers or short-term variables. The sample includes some dusty Mira variables (typically distinguished by smooth Mira-like light curves), two cataclysmic variables and a carbon star. In total, we have added 19 new objects to the broad class of eruptive variable YSOs with episodic accretion. Eruptive variable YSOs in our sample that were observed at bright states show higher accretion luminosities than the rest of the sample. Most of the eruptive variables differ from the established FUor and EXor subclasses, showing intermediate outburst durations and a mixture of their spectroscopic characteristics. This is in line with a small number of other recent discoveries. Since these previously atypical objects are now the majority amongst embedded members of the class, we propose a new classification for them as MNors. This term (pronounced emnor) follows V1647 Ori, the illuminating star of McNeil's Nebula

    The evolutionary status of the semiregular variable QYSge

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    Repeated spectroscopic observations made with the 6m telescope of yielded new data on the radial-velocity variability of the anomalous yellow supergiant QYSge. The strongest and most peculiar feature in its spectrum is the complex profile of NaI D lines, which contains a narrow and a very wide emission components. The wide emission component can be seen to extend from -170 to +120 km/s, and at its central part it is cut by an absorption feature, which, in turn, is split into two subcomponents by a narrow (16km/s at r=2.5) emission peak. An analysis of all the Vr values leads us to adopt for the star a systemic velocity of Vr=-21.1 km/s, which corresponds to the position of the narrow emission component of NaI. The locations of emission-line features of NaI D lines are invariable, which point to their formation in regions that are external to the supergiant's photosphere. Differential line shifts of about 10km/s are revealed. The absorption lines in the spectrum of QYSge have a substantial width of FWHM~45 km/s. The method of model atmospheres is used to determine the following parameters: Teff=6250K, lg g=2.0, and microturbulence Vt=4.5km/s. The metallicity of the star is found to be somewhat higher than the solar one with an average overabundance of iron-peak elements of [Met/H]=+0.20. The star is found to be slightly overabundant in carbon and nitrogen, [C/Fe]=+0.25, [N/Fe]=+0.27. The alpha-process elements Mg, Si, and Ca are slightly overabundant [alpha/H]=+0.12. The strong sodium excess, [Na/Fe]=+0.75, is likely to be due to the dredge-up of the matter processed in the NeNa cycle. Heavy elements of the s-process are underabundant relative to the Sun. On the whole, the observed properties of QYSge do not give grounds for including this star into the group of RCrB or RVTau-type type objects.Comment: 29 pages, 8 figures, 4 tables; accepted by Astrophys. Bulleti

    V2324Cyg - an F-type star with fast wind

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    For the first time high-resolution optical spectroscopy of the variable star V2324Cyg associated with the IR-source IRAS20572+4919 is made. More than 200 absorption features (mostly FeII, TiII, CrII, YII, BaII, and YII) are identified within the wavelength interval 4549-7880AA. The spectral type and rotation velocity of the star are found to be F0III and Vsini=69km/s, respectively. HI and NaID lines have complex PCyg-type profiles with an emission component. Neither systematic trend of radial velocity Vr with line depth Ro nor temporal variability of Vr have been found. We determined the average heliocentric radial velocity Vr=-16.8\pm 0.6km/s. The radial velocities inferred from the cores of the absorption components of the HÎČ\beta and NaI wind lines vary from -140 to -225km/s (and the expansion velocities of the corresponding layers, from about 120 to 210km/s). The maximum expansion velocity is found for the blue component of the split Hα\alpha absorption: 450km/s for December 12, 1995. The model atmospheres method is used to determine the star's parameters: Teff=7500K, log g=2.0, Οt\xi_t=6.0km/s, and metallicity, which is equal to the solar value. The main peculiarity of the chemical abundances pattern is the overabundance of lithium and sodium. The results cast some doubt on the classification of V2324Cyg as a post-AGB star.Comment: 28 pages, 6 figure

    BAs and boride III-V alloys

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    Boron arsenide, the typically-ignored member of the III-V arsenide series BAs-AlAs-GaAs-InAs is found to resemble silicon electronically: its Gamma conduction band minimum is p-like (Gamma_15), not s-like (Gamma_1c), it has an X_1c-like indirect band gap, and its bond charge is distributed almost equally on the two atoms in the unit cell, exhibiting nearly perfect covalency. The reasons for these are tracked down to the anomalously low atomic p orbital energy in the boron and to the unusually strong s-s repulsion in BAs relative to most other III-V compounds. We find unexpected valence band offsets of BAs with respect to GaAs and AlAs. The valence band maximum (VBM) of BAs is significantly higher than that of AlAs, despite the much smaller bond length of BAs, and the VBM of GaAs is only slightly higher than in BAs. These effects result from the unusually strong mixing of the cation and anion states at the VBM. For the BAs-GaAs alloys, we find (i) a relatively small (~3.5 eV) and composition-independent band gap bowing. This means that while addition of small amounts of nitrogen to GaAs lowers the gap, addition of small amounts of boron to GaAs raises the gap (ii) boron ``semi-localized'' states in the conduction band (similar to those in GaN-GaAs alloys), and (iii) bulk mixing enthalpies which are smaller than in GaN-GaAs alloys. The unique features of boride III-V alloys offer new opportunities in band gap engineering.Comment: 18 pages, 14 figures, 6 tables, 61 references. Accepted for publication in Phys. Rev. B. Scheduled to appear Oct. 15 200
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