3,011 research outputs found

    Relinquishing Control: What Romanian De Se Attitude Reports Teach Us About Immunity To Error Through Misidentification

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    Higginbotham argued that certain linguistic items of English, when used in indirect discourse, necessarily trigger first-personal interpretations. They are: the emphatic reflexive pronoun and the controlled understood subject, represented as PRO. PRO is special, in this respect, due to its imposing obligatory control effects between the main clause and its subordinates ). Folescu & Higginbotham, in addition, argued that in Romanian, a language whose grammar doesn’t assign a prominent role to PRO, de se triggers are correlated with the subjunctive mood of certain verbs. That paper, however, didn’t account for the grammatical diversity of the reports that display immunity to error through misidentification in Romanian: some of these reports are expressed by using de se triggers; others are not. Their IEM, moreover, is not systematically lexically controlled by the verbs, via their theta-roles; it is, rather, determined by the meaning of the verbs in question. Given the data from Romanian, I will argue, the phenomenon of IEM cannot be fully explained starting either from the syntactical or the lexical structure of a language

    Probing the Crust of the Neutron Star in EXO 0748-676

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    X-ray observations of quiescent X-ray binaries have the potential to provide insight into the structure and the composition of neutron stars. EXO 0748-676 had been actively accreting for over 24 yr before its outburst ceased in late 2008. Subsequent X-ray monitoring revealed a gradual decay of the quiescent thermal emission that can be attributed to cooling of the accretion-heated neutron star crust. In this work, we report on new Chandra and Swift observations that extend the quiescent monitoring to ~5 yr post-outburst. We find that the neutron star temperature remained at ~117 eV between 2009 and 2011, but had decreased to ~110 eV in 2013. This suggests that the crust has not fully cooled yet, which is supported by the lower temperature of ~95 eV that was measured ~4 yr prior to the accretion phase in 1980. Comparing the data to thermal evolution simulations reveals that the apparent lack of cooling between 2009 and 2011 could possibly be a signature of convection driven by phase separation of light and heavy nuclei in the outer layers of the neutron star.Comment: 9 pages, 4 tables, 3 figures. Minor revisions according to referee report. Accepted to Ap

    Spectral Modeling of SNe Ia Near Maximum Light: Probing the Characteristics of Hydro Models

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    We have performed detailed NLTE spectral synthesis modeling of 2 types of 1-D hydro models: the very highly parameterized deflagration model W7, and two delayed detonation models. We find that overall both models do about equally well at fitting well observed SNe Ia near to maximum light. However, the Si II 6150 feature of W7 is systematically too fast, whereas for the delayed detonation models it is also somewhat too fast, but significantly better than that of W7. We find that a parameterized mixed model does the best job of reproducing the Si II 6150 line near maximum light and we study the differences in the models that lead to better fits to normal SNe Ia. We discuss what is required of a hydro model to fit the spectra of observed SNe Ia near maximum light.Comment: 29 pages, 14 figures, ApJ, in pres

    High impact  =  high statistical standards? Not necessarily so.

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    What are the statistical practices of articles published in journals with a high impact factor? Are there differences compared with articles published in journals with a somewhat lower impact factor that have adopted editorial policies to reduce the impact of limitations of Null Hypothesis Significance Testing? To investigate these questions, the current study analyzed all articles related to psychological, neuropsychological and medical issues, published in 2011 in four journals with high impact factors: Science, Nature, The New England Journal of Medicine and The Lancet, and three journals with relatively lower impact factors: Neuropsychology, Journal of Experimental Psychology-Applied and the American Journal of Public Health. Results show that Null Hypothesis Significance Testing without any use of confidence intervals, effect size, prospective power and model estimation, is the prevalent statistical practice used in articles published in Nature, 89%, followed by articles published in Science, 42%. By contrast, in all other journals, both with high and lower impact factors, most articles report confidence intervals and/or effect size measures. We interpreted these differences as consequences of the editorial policies adopted by the journal editors, which are probably the most effective means to improve the statistical practices in journals with high or low impact factors

    Terahertz oscillations in an In<sub>0.53</sub>Ga<sub>0.47</sub>As submicron planar gunn diode

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    The length of the transit region of a Gunn diode determines the natural frequency at which it operates in fundamental mode – the shorter the device, the higher the frequency of operation. The long-held view on Gunn diode design is that for a functioning device the minimum length of the transit region is about 1.5ÎŒm, limiting the devices to fundamental mode operation at frequencies of roughly 60 GHz. Study of these devices by more advanced Monte Carlo techniques that simulate the ballistic transport and electron-phonon interactions that govern device behaviour, offers a new lower bound of 0.5ÎŒm, which is already being approached by the experimental evidence that has shown planar and vertical devices exhibiting Gunn operation at 600nm and 700nm, respectively. The paper presents results of the first ever THz submicron planar Gunn diode fabricated in In&lt;sub&gt;0.53&lt;/sub&gt;Ga&lt;sub&gt;0.47&lt;/sub&gt;A on an InP substrate, operating at a fundamental frequency above 300 GHz. Experimentally measured rf power of 28 ”W was obtained from a 600 nm long ×120 ”m wide device. At this new length, operation in fundamental mode at much higher frequencies becomes possible – the Monte Carlo model used predicts power output at frequencies over 300 GHz

    Investigation of mechanical losses of thin silicon flexures at low temperatures

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    The investigation of the mechanical loss of different silicon flexures in a temperature region from 5 to 300 K is presented. The flexures have been prepared by different fabrication techniques. A lowest mechanical loss of 3×10−83\times10^{-8} was observed for a 130 ÎŒ\mum thick flexure at around 10 K. While the mechanical loss follows the thermoelastic predictions down to 50 K a difference can be observed at lower temperatures for different surface treatments. This surface loss will be limiting for all applications using silicon based oscillators at low temperatures. The extraction of a surface loss parameter using different results from our measurements and other references is presented. We focused on structures that are relevant for gravitational wave detectors. The surface loss parameter αs\alpha_s = 0.5 pm was obtained. This reveals that the surface loss of silicon is significantly lower than the surface loss of fused silica.Comment: 16 pages, 7 figure

    Detectability of Terrestrial Planets in Multi-Planet Systems: Preliminary Report

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    We ask if Earth-like planets (terrestrial mass and habitable-zone orbit) can be detected in multi-planet systems, using astrometric and radial velocity observations. We report here the preliminary results of double-blind calculations designed to answer this question.Comment: 10 pages, 0 figure

    SN 2003du: Signatures of the Circumstellar Environment in a Normal Type Ia Supernova?

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    We present observations of the Type Ia supernova 2003du and report the detectionof an unusual, high-velocity component in the Ca II infrared triplet, similar tofeatures previously observed in SN 2000cx and SN 2001el. This feature exhibits a large expansion velocity (~18,000 km/s) which is nearly constant between -7 and +2 days relative to maximum light, and disappears shortly thereafter. Otherthan this feature, the spectral evolution and light curve resemble those of a normal SN Ia. We find that the Ca II feature can plausibly be caused by a dense shell formed when circumstellar material of solar abundance is overrun by the rapidly expanding outermost layers of the SN ejecta. Model calculations show that the optical and infrared spectra are remarkably unaffected by the circumstellar interaction. In particular, no hydrogen lines are detectable in either absorption or emission. The only qualitatively different features are the strong, high-velocity feature in the Ca II IR-triplet, and a somewhat weaker O I feature near 7,300 AA. The morphology and time evolution of these features provide an estimate for the amount of accumulated matter and an indication of the mixing in the dense shell. We apply these diagnostic tools to SN 2003du and infer that about 2 x 10^{-2} M_sun of solar abundance material may have accumulated in a circumstellar shell prior to the observations. Furthermore, the early light curve data imply that the circumstellar material was originally very close to the progenitor system, perhaps from an accretion disk, Roche lobe or common envelope.Comment: 35 Pages, 11 Figures, to appear in ApJ. Resubmission includes expanded discussion & new figures to match with accepted journal versio

    The X-ray properties of the magnetic cataclysmic variable UUColumbae

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    Aims. XMM-Newton observations to determine for the first time the broad-band X-ray properties of the faint, high galactic latitude intermediate polar UUCol are presented. Methods. We performed X-ray timing analysis in different energy ranges of the EPIC cameras, which reveals the dominance of the 863 s white dwarf rotational period. The spin pulse is strongly energy dependent. Weak variabilities at the beat 935 s and at the 3.5 h orbital periods are also observed, but the orbital modulation is detected only below 0.5 keV. Simultaneous UV and optical photometry shows that the spin pulse is anti-phased with respect to the hard X-rays. Analysis of the EPIC and RGS spectra reveals the complexity of the X-ray emission, which is composed of a soft 50 eV black–body component and two optically thin emission components at 0.2 keV and 11 keV strongly absorbed by dense material with an equivalent hydrogen column density of 1023 cm−2 that partially (50%) covers the X-ray source. Results. The complex X-ray and UV/optical temporal behaviour indicates that accretion occurs predominantly (∌80%) via a disc with a partial contribution (∌20%) directly from the stream. The main accreting pole dominates at high energies whilst the secondary pole mainly contributes in the soft X-rays and at lower energies. The bolometric flux ratio of the soft-to-hard X-ray emissions is found to be consistent with the prediction of the standard accretion shock model. We find the white dwarf in UUCol accretes at a low rate and possesses a low magnetic moment. It is therefore unlikely that UUCol will evolve into a moderate field strength polar, so that the soft X-ray intermediate polars still remain an enigmatic small group of magnetic cataclysmic variables
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