601 research outputs found

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    Online Only Classes and Critical Dialogue: Toward a Faustian Bargain Ideal for Virtual Education

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    As distance learning and Online Only Classes (OOCs) become more prevalent in higher education, it becomes increasingly urgent that critical-democratic educators continue to work toward a better understanding of liberatory praxis through technology. The goals of this essay are to explain why critical dialogue cannot be realized in OOCs, describe how blended brick-and-mortar/virtual classes may be advantageous for a critical agenda, and help orient future scholarship concerning critical pedagogy and technology toward a “Faustian bargain” ideal argued by Neil Postman. In order to reach these goals, I outline two types of educators that I believe have the most at stake in the use of the Internet in educational spaces, conceptualize how I understand critical dialogue, and use two different metaphors about technology to further understandings of the implications of technology in education

    Toward a Performative Understanding of Politeness

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    In this article, we argue that critical communication scholars have largely overlooked the study of politeness as a constitutive component of identity, culture, and power. We offer a critical-performative framework for critical scholars interested in studying politeness as a political, discursive, and embodied act. To develop this agenda, we first outline Brown and Levinson’s postpositivist theory of politeness. We then review three challenges to their use of intentionality, Grice’s cooperative principle, and Goffman’s concept of face. These challenges are located in interactional, traditional critical, and discursive understandings of politeness (respectively). Next, we show how a performative understanding of politeness both encompasses the three challenges and offers a way to understand the role of politeness in identity formation. We conclude by suggesting that ethnographic methods, informed by performance ethnography, provide analytical tools consistent with a performative understanding of politeness

    Critical Communication Pedagogy in/about/through the Communication Classroom

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    Critical Communication Pedagogy (CCP) signals a critical approach to Communication and Instruction scholarship. Critical signals a recognition that social reality is inherently political and encourages individuals to work with/in communities to identify, intervene into, and change oppressive systems. Communication and Instruction scholarship refers to (a) research concerning how to teach communication principles, theories, or knowledge (i.e., Communication Pedagogy or Communication Education) and (b) research about communication as it manifests in or about all types of educational spaces (i.e., Instructional Communication). CCP is not guided by a single methodology; rather, it signifies both an intellectual tradition and an umbrella term for critical approaches to Communication Pedagogy and Instructional Communication

    Spitzer IRAC Low Surface Brightness Observations of the Virgo Cluster

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    We present 3.6 and 4.5 micron Spitzer IRAC imaging over 0.77 square degrees at the Virgo cluster core for the purpose of understanding the formation mechanisms of the low surface brightness intracluster light features. Instrumental and astrophysical backgrounds that are hundreds of times higher than the signal were carefully characterized and removed. We examine both intracluster light plumes as well as the outer halo of the giant elliptical M87. For two intracluster light plumes, we use optical colors to constrain their ages to be greater than 3 & 5 Gyr, respectively. Upper limits on the IRAC fluxes constrain the upper limits to the masses, and optical detections constrain the lower limits to the masses. In this first measurement of mass of intracluster light plumes we find masses in the range of 5.5 x 10^8 - 4.5 x 10^9 and 2.1 x 10^8 - 1.5 x 10^9 solar masses for the two plumes for which we have coverage. Given their expected short lifetimes, and a constant production rate for these types of streams, integrated over Virgo's lifetime, they can account for the total ICL content of the cluster implying that we do not need to invoke ICL formation mechanisms other than gravitational mechanisms leading to bright plumes. We also examined the outer halo of the giant elliptical M87. The color profile from the inner to outer halo of M87 (160 Kpc) is consistent with either a flat or optically blue gradient, where a blue gradient could be due to younger or lower metallicity stars at larger radii. The similarity of the age predicted by both the infrared and optical colors (> few Gyr) indicates that the optical measurements are not strongly affected by dust extinction.Comment: 16 pages including appendix, 9 figures, ApJ accepte

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    Intragroup diffuse light in compact groups of galaxies II. HCG 15, 35 and 51

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    This continuing study of intragroup light in compact groups of galaxies aims to establish new constraints to models of formation and evolution of galaxy groups, specially of compact groups, which are a key part in the evolution of larger structures, such as clusters. In this paper we present three additional groups (HCG 15, 35 and 51) using deep wide field BB and RR band images observed with the LAICA camera at the 3.5m telescope at the Calar Alto observatory (CAHA). This instrument provides us with very stable flatfielding, a mandatory condition for reliably measuring intragroup diffuse light. The images were analyzed with the OV\_WAV package, a wavelet technique that allows us to uncover the intragroup component in an unprecedented way. We have detected that 19, 15 and 26% of the total light of HCG 15, 35 and 51, respectively, is in the diffuse component, with colours that are compatible with old stellar populations and with mean surface brightness that can be as low as 28.4Bmagarcsec−228.4 {\rm B mag arcsec^{-2}}. Dynamical masses, crossing times and mass to light ratios were recalculated using the new group parameters. Also tidal features were analyzed using the wavelet technique.Comment: 12 pages, 5 figures. Accepted for publication in MNRAS. See http://www.eso.org/~cdarocha/publications/DaRochaetal2008_IGL_HCG.pdf for full resolution version. Complementary reference adde

    The outer halos of elliptical galaxies

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    Recent progress is summarized on the determination of the density distributions of stars and dark matter, stellar kinematics, and stellar population properties, in the extended, low surface brightness halo regions of elliptical galaxies. With integral field absorption spectroscopy and with planetary nebulae as tracers, velocity dispersion and rotation profiles have been followed to ~4 and ~5-8 effective radii, respectively, and in M87 to the outer edge at ~150 kpc. The results are generally consistent with the known dichotomy of elliptical galaxy types, but some galaxies show more complex rotation profiles in their halos and there is a higher incidence of misalignments, indicating triaxiality. Dynamical models have shown a range of slopes for the total mass profiles, and that the inner dark matter densities in ellipticals are higher than in spiral galaxies, indicating earlier assembly redshifts. Analysis of the hot X-ray emitting gas in X-ray bright ellipticals and comparison with dynamical mass determinations indicates that non-thermal components to the pressure may be important in the inner ~10 kpc, and that the properties of these systems are closely related to their group environments. First results on the outer halo stellar population properties do not yet give a clear picture. In the halo of one bright galaxy, lower [alpha/Fe] abundances indicate longer star formation histories pointing towards late accretion of the halo. This is consistent with independent evidence for on-going accretion, and suggests a connection to the observed size evolution of elliptical galaxies with redshift.Comment: 8 pages. Invited review to appear in the proceedings of "Galaxies and their Masks" eds. Block, D.L., Freeman, K.C. & Puerari, I., 2010, Springer (New York
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