Urgency, Opportunity, and Frustration: Implementing the Intelligence Reform and Terrorism Prevention Act of 2004

A terrorist organization targets America\u27s airlines, igniting domestic panic and finger-pointing in Washington. The plot is hatched in a distant Muslim-majority nation-a country with which the United States has maintained a historically volatile relationship and in which multiple attacks against U.S. citizens originated in the past decade. A key perpetrator hails from another country where Islamic extremism is known to thrive, and he traveled to other countries en route to the United States, evading airport security. With the benefit of hindsight, the plot now appears crystal clear. Prior to the incident, multiple U.S. and foreign government agencies possessed bits and pieces of relevant information. There was no smoking gun that in itself could have foiled the attack. But if the disparate intelligence had been integrated properly into a coherent picture, perhaps the terrorist attempt could have been thwarted at an earlier stage

Interacting Galaxies in the A901/902 Supercluster with STAGES

We present a study of galaxy mergers and the influence of environment in the Abell 901/902 supercluster at z~0.165. We use HST ACS F606W data from the STAGES survey, COMBO-17, Spitzer 24um, and XMM-Newton X-ray data. Our analysis utilizes both a visual classification system, and quantitative CAS parameters to identify systems which show evidence of a recent or ongoing merger of mass ratio >1/10. Our results are: (1) After visual classification and minimizing the contamination from false projection pairs, we find that the merger fraction f_merge is 0.023+/-0.007. The estimated fractions of likely major mergers, likely minor mergers, and ambiguous cases are 0.01+/-0.004, 0.006+/-0.003, and 0.007+/-0.003, respectively. (2) The mergers lie outside the cluster core of radius R < 0.25 Mpc: the lack of mergers in the core is likely due to the large galaxy velocity dispersion in the core. Mergers populate the region (0.25 Mpc < R <= 2 Mpc) between the core and outskirt. In this region, the estimated frequency of mergers is similar to those seen at typical group overdensities. This suggests ongoing growth of the clusters via accretion of group and field galaxies. (3) We compare our observed merger fraction with those reported in other clusters and groups out to z~0.4. Existing data points on the merger fraction for L<= L* galaxies in clusters allow for a range of evolutionary scenarios. (4) The fraction of mergers, which lie on the blue cloud is 80%+/-18% versus 34%+/-7% for non-interacting galaxies, implying that interacting galaxies are preferentially blue. (5) The average SFR, based on UV or UV+IR data, is enhanced by a factor of ~1.5 to 2 in mergers compared to non-interacting galaxies. However, mergers in the clusters contribute only a small fraction (between 10% and 15%) of the total SFR density.(Abridged)Comment: Accepted for publication in ApJ. 34 pages, 16 figures. Version with full resolution figures available at: http://www.as.utexas.edu/~alh/apj/int/ ; updated abridged abstrac

History Of Galaxy Interactions And Their Impact On Star Formation Over The Last 7 Gyr From GEMS

We perform a comprehensive estimate of the frequency of galaxy mergers and their impact on star formation over z similar to 0.24-0.80 (lookback time T(b) similar to 3-7 Gyr) using similar to 3600 (M >= 1 x 10(9) M(circle dot)) galaxies with GEMS Hubble Space Telescope, COMBO-17, and Spitzer data. Our results are as follows. (1) Among similar to 790 high-mass (M >= 2.5 x 10(10) M(circle dot)) galaxies, the visually based merger fraction over z similar to 0.24-0.80, ranges from 9% +/- 5% to 8% +/- 2%. Lower limits on the major merger and minor merger fraction over this interval range from 1.1% to 3.5%, and 3.6% to 7.5%, respectively. This is the first, albeit approximate, empirical estimate of the frequency of minor mergers over the last 7 Gyr. Assuming a visibility timescale of similar to 0.5 Gyr, it follows that over T(b) similar to 3-7 Gyr, similar to 68% of high-mass systems have undergone a merger of mass ratio > 1/10, with similar to 16%, 45%, and 7% of these corresponding respectively to major, minor, and ambiguous "major or minor" mergers. The average merger rate is similar to a few x 10(-4) galaxies Gyr(-1) Mpc(-3). Among similar to 2840 blue-cloud galaxies of mass M >= 1.0 x 10(9) M(circle dot), similar results hold. (2) We compare the empirical merger fraction and merger rate for high-mass galaxies to three. cold dark matter-based models: halo occupation distribution models, semi-analytic models, and hydrodynamic SPH simulations. We find qualitative agreement between observations and models such that the (major+minor) merger fraction or rate from different models bracket the observations, and show a factor of 5 dispersion. Near-future improvements can now start to rule out certain merger scenarios. (3) Among similar to 3698 M >= 1.0 x 10(9) M(circle dot) galaxies, we find that the mean star formation rate (SFR) of visibly merging systems is only modestly enhanced compared to non-interacting galaxies over z similar to 0.24-0.80. Visibly merging systems only account for a small fraction (< 30%) of the cosmic SFR density over T(b) similar to 3-7 Gyr. This complements the results of Wolf et al. over a shorter time interval of T(b) similar to 6.2-6.8 Gyr, and suggests that the behavior of the cosmic SFR density over the last 7 Gyr is predominantly shaped by non-interacting galaxies.National Aeronautics and Space Administration (NASA) NAG5-13063, NAS5-26555, NAG5-13102NSF AST-0607748STScI G0-10395Deutsche ForschungsgemeinschaftNSFC 10773030, 10833006NRC-HIASTFCSpace Telescope Science Institute GO-9500Astronom

2006 Annual Report of the U.S. Intelligence Community (2007)

First page of documen

Is the internet really new after all?: the determinants of telecommunications diffusion in historical perspective

Recent anxieties over the digital divide have centered on the observation that uptake of the Internet is shaped by a number of identifiable, place-based factors. Yet is the Internet any more a product of material geography than previous communication technologies? Our contribution in this article seeks to address this question by deploying quantitative techniques to examine whether the country-level adoption of past communication networks—mail, telegrams, and telephone—was shaped by similar socioeconomic factors. Our results reveal striking similarities in the domestic attributes—income, education, and trade openness—influencing rates of uptake across all four technologies during their major periods of diffusion. © 2011 by Association of American Geographers