10 research outputs found
Galaxies with a central minimum in stellar luminosity density
We used Hubble Space Telescope WFPC2 images to identify six early-type galaxies with surface brightness profiles that decrease inward over a limited range of radii near their centers. The inferred luminosity density profiles of these galaxies have local minima interior to their core break radii. NGC 3706 harbors a high surface brightness ring of starlight with radius ≈20 pc. Its central structure may be related to that in the double-nucleus galaxies M31 and NGC 4486B. NGC 4406 and NGC 6876 have nearly flat cores that, on close inspection, are centrally depressed. Colors for both galaxies imply that this is not due to dust absorption. The surface brightness distributions of both galaxies are consistent with stellar tori that are more diffuse than the sharply defined system in NGC 3706. The remaining three galaxies are the brightest cluster galaxies in A260, A347, and A3574. Color information is not available for these objects, but they strongly resemble NGC 4406 and NGC 6876 in their cores. The thin ring in NGC 3706 may have formed dissipatively. The five other galaxies resemble the endpoints of some simulations of the merging of two gas-free stellar systems, each harboring a massive nuclear black hole. In one version of this scenario, diffuse stellar tori are produced when stars initially bound to one black hole are tidally stripped away by the second black hole. Alternatively, some inward-decreasing surface brightness profiles may reflect the ejection of stars from a core during the hardening of the binary black hole created during the merger
Physical Inactivity during Leisure Time among Older Adults—Behavioral Risk Factor Surveillance System, 2005
Gentle Exercise of 40 Minutes with Dietary Counseling is Effective in Treating Metabolic Syndrome
Analyzing Free-Living Physical Activity of Older Adults in Different Environments Using Body-Worn Activity Monitors
Estimating Absolute and Relative Physical Activity Intensity Across Age via Accelerometry in Adults
Use of Accelerometry to Measure Physical Activity in Older Adults at Risk for Mobility Disability
German Industrial Policy: An Overview
The German political economy and its comparative advantage in the production of high quality, internationally competitive manufactured goods has long been an object of study. Yet a remarkable lack of consensus exists as to the key institutional features of the German model, particularly regarding the role of the national state in industrial policy. This paper argues, in the face of widespread calls for withdrawal of German state institutional frameworks governing the labour market in particular, that the German framework is not as rigid as claimed, and that the innovative capabilities of German industry would be best served by incremental changes rather than wholesale dismantling of existing structures.