669 research outputs found
Chain Galaxies in the Tadpole ACS Field
Colors and magnitudes were determined for 69 chain galaxies, 58 other linear
structures, 32 normal edge-on galaxies, and all of their large star formation
clumps in the HST ACS field of the Tadpole galaxy. Redshifts of 0.5 to 2 are
inferred from comparisons with published color-evolution models. The linear
galaxies have no red nuclear bulges like the normal disk galaxies in our field,
but the star formation clumps in each have about the same colors and
magnitudes. Light profiles along the linear galaxies tend to be flat, unlike
the exponential profiles of normal galaxies. Although the most extreme of the
linear objects look like beaded filaments, they are all probably edge-on disks
that will evolve to late Hubble type galaxies. The lack of an exponential
profile is either the result of a dust scale height that is comparable to the
stellar scale height, or an intrinsically irregular structure. Examples of
galaxies that could be face-on versions of linear galaxies are shown. They have
an irregular clumpy structure with no central bulge and with clump colors and
magnitudes that are comparable to those in the linears. Radiative transfer
solutions to the magnitudes and surface brightnesses of inclined dusty galaxies
suggest that edge-on disks should become more prominent near the detection
limit for surface brightness. The surface brightness distribution of the
edge-on galaxies in this field confirm this selection effect. The star
formation regions are much more massive than in modern galaxies, averaging up
to 10^9 Msun for kpc scales.Comment: 15 pages, 9 figures, accepted for ApJ, 603, March 1, 200
Spectroscopy of Nine Cataclysmic Variable Stars
We present optical spectroscopy of nine cataclysmic binary stars, mostly
dwarf novae, obtained primarily to determine orbital periods Porb. The stars
and their periods are LX And, 0.1509743(5) d; CZ Aql, 0.2005(6) d; LU Cam,
0.1499686(4) d; GZ Cnc, 0.0881(4) d; V632 Cyg, 0.06377(8) d; V1006 Cyg,
0.09903(9) d; BF Eri, 0.2708804(4) d; BI Ori, 0.1915(5) d; and FO Per, for
which Porb is either 0.1467(4) or 0.1719(5) d.
Several of the stars proved to be especially interesting. In BF Eri, we
detect the absorption spectrum of a secondary star of spectral type K3 +- 1
subclass, which leads to a distance estimate of approximately 1 kpc. However,
BF Eri has a large proper motion (100 mas/yr), and we have a preliminary
parallax measurement that confirms the large proper motion and yields only an
upper limit for the parallax. BF Eri's space velocity is evidently large, and
it appears to belong to the halo population. In CZ Aql, the emission lines have
strong wings that move with large velocity amplitude, suggesting a
magnetically-channeled accretion flow. The orbital period of V1006 Cyg places
it squarely within the 2- to 3-hour "gap" in the distribution of cataclysmic
binary orbital periods.Comment: 31 pages, 5 postscript and one PNG figure. Accepted for PAS
Empathy, engagement, entrainment: the interaction dynamics of aesthetic experience
A recent version of the view that aesthetic experience is based in empathy as inner
imitation explains aesthetic experience as the automatic simulation of actions,
emotions, and bodily sensations depicted in an artwork by motor neurons in the brain. Criticizing the simulation theory for committing to an erroneous concept of empathy and failing to distinguish regular from aesthetic experiences of art, I advance an alternative, dynamic approach and claim that aesthetic experience is enacted and skillful, based in the recognition of othersâ experiences as distinct from oneâs own. In combining insights from mainly psychology, phenomenology, and cognitive science, the dynamic approach aims to explain the emergence of aesthetic experience in terms of the reciprocal interaction between viewer and artwork. I argue that aesthetic experience emerges by participatory sense-making and revolves around movement as a means for creating meaning. While entrainment merely plays a preparatory part in this, aesthetic engagement constitutes the phenomenological side of coupling to an artwork and provides the context for exploration, and eventually for moving, seeing, and feeling with art. I submit that aesthetic experience emerges from bodily and emotional engagement with works of art via the complementary processes of the perceptionâaction and motionâemotion loops. The former involves the embodied
visual exploration of an artwork in physical space, and progressively structures and organizes visual experience by way of perceptual feedback from body movements made in response to the artwork. The latter concerns the movement qualities and shapes of implicit and explicit bodily responses to an artwork that cue emotion and thereby modulate over-all affect and attitude. The two processes cause the viewer to bodily and emotionally move with and be moved by individual works of art, and consequently to recognize another psychological orientation than her own, which explains how art can cause feelings of insight or awe and disclose aspects of life that are unfamiliar or novel to the viewer
Critical Race Theory and Education: racism and anti-racism in educational theory and praxis
What is Critical Race Theory (CRT) and what does it offer educational researchers and practitioners outside the US? This paper addresses these questions by examining the recent history of antiracist research and policy in the UK. In particular, the paper argues that conventional forms of antiracism have proven unable to keep pace with the development of increasingly racist and exclusionary education polices that operate beneath a veneer of professed tolerance and diversity. In particular, contemporary antiracism lacks clear statements of principle and theory that risk reinventing the wheel with each new study; it is increasingly reduced to a meaningless slogan; and it risks appropriation within a reformist âcan doâ perspective dominated by the de-politicized and managerialist language of school effectiveness and improvement. In contrast, CRT offers a genuinely radical and coherent set of approaches that could revitalize critical research in education across a range of inquiries, not only in self-consciously "multicultural" studies. The paper reviews the developing terrain of CRT in education, identifying its key defining elements and the conceptual tools that characterise the work. CRT in education is a fast changing and incomplete project but it can no longer be ignored by the academy beyond North America
Education policy as an act of white supremacy: whiteness, critical race theory and education reform
The paper presents an empirical analysis of education policy in England that is informed by recent developments in US critical theory. In particular, I draw on âwhiteness studiesâ and the application of Critical Race Theory (CRT). These perspectives offer a new and radical way of conceptualising the role of racism in education. Although the US literature has paid little or no regard to issues outside North America, I argue that a similar understanding of racism (as a multifaceted, deeply embedded, often taken-for-granted aspect of power relations) lies at the heart of recent attempts to understand institutional racism in the UK. Having set out the conceptual terrain in the first half of the paper, I then apply this approach to recent changes in the English education system to reveal the central role accorded the defence (and extension) of race inequity. Finally, the paper touches on the question of racism and intentionality: although race inequity may not be a planned and deliberate goal of education policy neither is it accidental. The patterning of racial advantage and inequity is structured in domination and its continuation represents a form of tacit intentionality on the part of white powerholders and policy makers. It is in this sense that education policy is an act of white supremacy. Following others in the CRT tradition, therefore, the paperâs analysis concludes that the most dangerous form of âwhite supremacyâ is not the obvious and extreme fascistic posturing of small neonazi groups, but rather the taken-for-granted routine privileging of white interests that goes unremarked in the political mainstream
Statistical \u3cem\u3eÎł\u3c/em\u3e Rays in the Analysis of Surrogate Nuclear Reactions
The surrogate nuclear reaction method is being applied in many efforts to indirectly determine neutron-induced reaction cross sections on short-lived isotopes. This technique aims to extract accurate (n,Îł) cross sections from measured decay properties of the compound nucleus of interest (created using a different reaction). The advantages and limitations of a method that identifies the Îł-ray decay channel by detecting any high-energy (âstatisticalâ) Îł ray emitted during the relaxation of the compound nucleus were investigated. Data collected using the Silicon Telescope Array for Reaction Studies and Livermore-Berkeley Array for Collaborative Experiments silicon and germanium detector arrays were used to study the decay of excited gadolinium nuclei following inelastic proton scattering. In many cases, this method of identifying the Îł-ray decay channel can simplify the experimental data collection and greatly improve the detection efficiency for Îł-ray cascades. The results show sensitivity to angular-momentum differences between the surrogate reaction and the desired (n,Îł) reaction similar to an analysis performed using low-lying discrete transitions even when ratios of cross sections are considered
- âŠ