1,055 research outputs found

    The attitudinal work of news journalism images – a search for visual and verbal analogues

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    This paper is concerned with the potential of journalistic still images (photographs, pictorial layouts, artwork and political cartooning) to position readers/viewers to take a positive or negative view of the people, events and situations which are the subject matter of news journalism coverage. Referencing prior work by Economou (2009) and Swain (2012), it offers an account of the mechanisms, the particular visual qualities and compositional arrangements, by which such attitudinal effects are achieved. Its primary concern is exploring the grounds by which the mechanisms through which journalistic images activate positive or negative attitudes might be treated as analogous to related verbal expressions of attitude. In developing this discussion, it references and revisits the account of the language of evaluation developed within the Appraisal literature (Martin and White 2005). It proposes that in order to identify analogues to verbal expressions which, on the one hand, explicitly assert attitudinal assessments and which, on the other hand, activate attitudinal positions through implication and association, it is useful to attend to the following issues: (1) the salience or detectability of the author’s subjective presence in the text as the communicative agent who puts an attitudinal meaning into play; (2) the stability of the attitudinal associations of a given expression across multiple contexts of use; (3) the role of the reader in supplying attitudinal interpretations or inferences; (4) the terms under which relations of author-reader solidarity are negotiated or put at risk but the expression currently under consideration

    Strong singularity of singular masas in II<sub>1</sub> factors

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    A singular masa A in a II1 factor N is defined by the property that any unitary w &#8712; N for which A=wAw* must lie in A. A strongly singular masa A is one that satisfies the inequality ||EA- EwAw*||&#8734;,2 &#8805;||w- EA(w)||2 for all unitaries w &#8712; N where EA is the conditional expectation of N onto A, and ||&#8901;||&#8734;,2 is defined for bounded maps &#934; : N &#8594; N by sup{||&#934; (x)||2:x &#8712; N,||x||&#8804;1}. Strong singularity easily implies singularity, and the main result of this paper shows the reverse implication

    Perturbations of C*-algebraic invariants

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    Kadison and Kastler introduced a metric on the set of all C*-algebras on a fixed Hilbert space. In this paper structural properties of C*-algebras which are close in this metric are examined. Our main result is that the property of having a positive answer to Kadison’s similarity problem transfers to close C*-algebras. In establishing this result we answer questions about closeness of commutants and tensor products when one algebra satisfies the similarity property. We also examine K-theory and traces of close C*-algebras, showing that sufficiently close algebras have isomorphic Elliott invariants when one algebra has the similarity property

    pdFOAM: A PIC-DSMC code for near-earth plasma-body interactions

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    Understanding the interaction of the near-Earth space environment with orbiting bodies is critical, both from a design and scientific perspective. In Low Earth Orbit (LEO), the interaction between the Ionosphere and orbiting objects is well studied from a charging perspective. Not well understood is the effect of the Ionosphere on the motion of LEO objects i.e. charged aerodynamics. This paper presents the implementation, validation, and verification of the hybrid electrostatic Particle-in-Cell (PIC) - Direct Simulation Monte Carlo (DSMC) code, pdFOAM, to study both the neutral and charged particle aerodynamics of LEO objects. The 2D aerodynamic interaction of a cylinder with a fixed uniform surface potential of −50 V in mesothermal O+ and H+ plasmas representative of ionospheric conditions is investigated. New insights into the role of bounded ion jets and their effect on surface forces are presented. O+ bounded ion jets are observed to cause a 4.4% increase in direct Charged Particle Drag (dCPD), while H+ ion jets produce a net reduction in H+ dCPD by 23.7% i.e. they cause a thrust force. As a result, this paper concludes the study of charged aerodynamics in LEO requires a self-consistent modelling tool, such as pdFOAM

    Quantum-fluctuation-induced repelling interaction of quantum string between walls

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    Quantum string, which was brought into discussion recently as a model for the stripe phase in doped cuprates, is simulated by means of the density-matrix-renormalization-group method. String collides with adjacent neighbors, as it wonders, owing to quantum zero-point fluctuations. The energy cost due to the collisions is our main concern. Embedding a quantum string between rigid walls with separation d, we found that for sufficiently large d, collision-induced energy cost obeys the formula \sim exp (- A d^alpha) with alpha=0.808(1), and string's mean fluctuation width grows logarithmically \sim log d. Those results are not understood in terms of conventional picture that the string is `disordered,' and only the short-wave-length fluctuations contribute to collisions. Rather, our results support a recent proposal that owing to collisions, short-wave-length fluctuations are suppressed, but instead, long-wave-length fluctuations become significant. This mechanism would be responsible for stabilizing the stripe phase

    The Tensor to Scalar Ratio of Phantom Dark Energy Models

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    We investigate the anisotropies in the cosmic microwave background in a class of models which possess a positive cosmic energy density but negative pressure, with a constant equation of state w = p/rho < -1. We calculate the temperature and polarization anisotropy spectra for both scalar and tensor perturbations by modifying the publicly available code CMBfast. For a constant initial curvature perturbation or tensor normalization, we have calculated the final anisotropy spectra as a function of the dark energy density and equation of state w and of the scalar and tensor spectral indices. This allows us to calculate the dependence of the tensor-to-scalar ratio on w in a model with phantom dark energy, which may be important for interpreting any future detection of long-wavelength gravitational waves.Comment: 5 pages, 4 figure

    Renormalization-group running of the cosmological constant and its implication for the Higgs boson mass in the Standard Model

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    The renormalization-group equation for the zero-point energies associated with vacuum fluctuations of massive fields from the Standard Model is examined. Our main observation is that at any scale the running is necessarily dominated by the heaviest degrees of freedom, in clear contradistinction with the Appelquist & Carazzone decoupling theorem. Such an enhanced running would represent a disaster for cosmology, unless a fine-tuned relation among the masses of heavy particles is imposed. In this way, we obtain mH550GeVm_H \simeq 550 GeV for the Higgs mass, a value safely within the unitarity bound, but far above the more stringent triviality bound for the case when the validity of the Standard Model is pushed up to the grand unification (or Planck) scale.Comment: 11 pages, LaTex2

    Critical temperature for the two-dimensional attractive Hubbard Model

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    The critical temperature for the attractive Hubbard model on a square lattice is determined from the analysis of two independent quantities, the helicity modulus, ρs\rho_s, and the pairing correlation function, PsP_s. These quantities have been calculated through Quantum Monte Carlo simulations for lattices up to 18×1818\times 18, and for several densities, in the intermediate-coupling regime. Imposing the universal-jump condition for an accurately calculated ρs\rho_s, together with thorough finite-size scaling analyses (in the spirit of the phenomenological renormalization group) of PsP_s, suggests that TcT_c is considerably higher than hitherto assumed.Comment: 5 pages, 6 figures. Accepted for publication in Phys. Rev.

    Black Holes from Nucleating Strings

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    We evaluate the probability that a loop of string that has spontaneously nucleated during inflation will form a black hole upon collapse, after the end of inflation. We then use the observational bounds on the density of primordial black holes to put constraints on the parameters of the model. Other constraints from the distortions of the microwave background and emission of gravitational radiation by the loops are considered. Also, observational constraints on domain wall nucleation and monopole pair production during inflation are briefly discussed.Comment: 27 pages, tutp-92-

    Constraining the dark energy with galaxy clusters X-ray data

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    The equation of state characterizing the dark energy component is constrained by combining Chandra observations of the X-ray luminosity of galaxy clusters with independent measurements of the baryonic matter density and the latest measurements of the Hubble parameter as given by the HST key project. By assuming a spatially flat scenario driven by a "quintessence" component with an equation of state px=ωρxp_x = \omega \rho_x we place the following limits on the cosmological parameters ω\omega and Ωm\Omega_{\rm{m}}: (i) 1ω0.55-1 \leq \omega \leq -0.55 and Ωm=0.320.014+0.027\Omega_{\rm m} = 0.32^{+0.027}_{-0.014} (1σ\sigma) if the equation of state of the dark energy is restricted to the interval 1ω<0-1 \leq \omega < 0 (\emph{usual} quintessence) and (ii) ω=1.290.792+0.686\omega = -1.29^{+0.686}_{-0.792} and Ωm=0.310.034+0.037\Omega_{\rm{m}} = 0.31^{+0.037}_{-0.034} (1σ1\sigma) if ω\omega violates the null energy condition and assume values <1< -1 (\emph{extended} quintessence or ``phantom'' energy). These results are in good agreement with independent studies based on supernovae observations, large-scale structure and the anisotropies of the cosmic background radiation.Comment: 6 pages, 4 figures, LaTe
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