Assessing Responsibility: Fixing Blame versus Fixing Problems

In the midst of even the most tragic circumstances attending the aftermath of disaster, and co-existing with a host of complex emotions, arises a practical consideration: how might similar tragedies be prevented in the future? The complexity of such situations must not be neglected. More than mere prevention must usually be taken into consideration. But the practical question is of considerable importance. In what follows, I will offer some reasons for being concerned that efforts to fix the problem -- efforts, that is, directed toward insuring that similar tragedies do not occur in the future -- can easily be obstructed by attempts to fix blame -- that is, efforts directed toward determining which agent among those involved is guilty of wrong-doing. This is the case, I shall contend, even where some agent or another really is guilty of wrong-doing. The problem is further complicated by a pervasive human tendency to imagine that some agent or another must be responsible in some way for any tragedy that occurs -- even when this is not really true -- but its influence is not at all limited to such cases. As I shall suggest, philosophical attitudes toward issues of determinism and free will may be implicated in the different approaches people take to the problem of assessing what has gone wrong in a particular case and how to fix it, but such deep philosophical problems need not be resolved here. The point is not that humans are never guilty of wrong-doing (since their actions, the argument might go, are all products of outside forces), but rather that whatever the case may be about guilt, tracking down guilty persons is a different business from fixing institutionally-embedded problems so as to lessen the likelihood of their recurrence

A note on Freiman's theorem in vector spaces

We show that if A is a subset of F_2^n and |A+A| < K|A| then A is contained in a subspace of size at most 2^{O(K^{3/2}log K)}|A|. This improves on the previous best of 2^{O(K^2)}.Comment: 9 pp. Corrected typos. Updated references

Semiclassical Mechanics of Rotons

The elementary excitations in superfluid liquid He-4 named rotons have an unusual dispersion curve. The energy is an approximately quadratic function of (p-p_0), the difference between the magnitude of the momentum p and a characteristic value p_0. As a result, while for p>p_0 a roton has its (group) velocity parallel to its momentum, when p<p_0 the velocity and momentum are antiparallel. When p=p_0, the roton has non-zero momentum but zero velocity. These kinematic properties lead to unusual trajectories when rotons scatter or experience external forces. This paper examines this behavior in the classical (ray optics) limit, where the roton wavelength is small compared with all other dimensions. Several experiments illustrate these effects. The examples are interesting in themselves, and also offer unconventional pedagogical possibilities.Comment: 21 pp, 7 figures, submitted to Contemporary Physic

X ray absorption by dark nebulae (HEAO-2 guest investigator program)

A study is described of data obtained from the Imaging Proportional Counter (IPC) x ray detector aboard the HEAO-2 satellite (Einstein Observatory). The research project involved a search for absorption of diffuse low energy x ray background emission by galactic dark nebulae. The commonly accepted picture that the bulk of the C band emission originates locally, closer that a few hundred parsec, and the bulk of the M band emission originates farther away than a few hundred parsec, was tested. The idea was to look for evidence of absorption of the diffuse background radiation by nearby interstellar clouds

The Role of Starburst-AGN composites in Luminous Infrared Galaxy Mergers: Insights from the New Optical Classification Scheme

We investigate the fraction of starbursts, starburst-AGN composites, Seyferts, and LINERs as a function of infrared luminosity (L_IR) and merger progress for ~500 infrared-selected galaxies. Using the new optical classifications afforded by the extremely large data set of the Sloan Digital Sky Survey, we find that the fraction of LINERs in IR-selected samples is rare (< 5%) compared with other spectral types. The lack of strong infrared emission in LINERs is consistent with recent optical studies suggesting that LINERs contain AGN with lower accretion rates than in Seyfert galaxies. Most previously classified infrared-luminous LINERs are classified as starburst-AGN composite galaxies in the new scheme. Starburst-AGN composites appear to "bridge" the spectral evolution from starburst to AGN in ULIRGs. The relative strength of the AGN versus starburst activity shows a significant increase at high infrared luminosity. In ULIRGs (L_IR >10^12 L_odot), starburst-AGN composite galaxies dominate at early--intermediate stages of the merger, and AGN galaxies dominate during the final merger stages. Our results are consistent with models for IR-luminous galaxies where mergers of gas-rich spirals fuel both starburst and AGN, and where the AGN becomes increasingly dominant during the final merger stages of the most luminous infrared objects.Comment: 30 pages, 19 figures, 10 tables, ApJ accepte

Limits on diffuse X-ray emission from M101

Observed limits on diffuse X-ray emission from M101 require that the temperature of any coronal or matrix hot gas which is radiating an appreciable part ( 10%) of the average supernova power be less than 10(5.7)K. Furthermore, the fraction of the galactic plane occupied by hot buttles similar to the one which apparently surrounds the Sun is at most 25% in the region between 10 kpc and 20 kpc from the galactic center

‘It’s better than daytime television’: questioning the socio-spatial impacts of massage parlours on residential communities

It has been shown that street sex work is problematic for some communities, but there is less evidence of the effects of brothels. Emerging research also suggests that impact discourses outlined by residential communities and in regulatory policies should be critiqued, because they are often based on minority community voices, and limited tangible evidence is used to masquerade wider moral viewpoints about the place of sex work. Using a study of residents living in close proximity to brothels in Blackpool, this paper argues that impact is socially and spatially fluid. Impact needs to be evaluated in a more nuanced manner, which is considerate of the heterogeneity of (even one type of) sex work, and the community in question. Brothels in Blackpool had a variety of roles in the everyday socio-spatial fabric; thus also questioning the common assumption that sex work only impacts negatively on residential communities