Star and cluster formation in extreme environments

Current empirical evidence on the star-formation processes in the extreme, high-pressure environments induced by galaxy encounters (mostly based on high-resolution Hubble Space Telescope observations) strongly suggests that star CLUSTER formation is an important and perhaps even the dominant mode of star formation in such starburst events. The sizes, luminosities, and mass estimates of the young massive star clusters (YMCs) are entirely consistent with what is expected for young Milky Way-type globular clusters (GCs). Recent evidence lends support to the scenario that GCs, which were once thought to be the oldest building blocks of galaxies, are still forming today. Here, I present a novel empirical approach to assess the shape of the initial-to-current YMC mass functions, and hence their possible survival chances for a Hubble time.Comment: 6 pages, LaTeX with Kluwer style files included; to appear in: "Starbursts - from 30 Doradus to Lyman break galaxies" (Cambridge UK, September 2004; talk summary), Astrophysics & Space Science Library, eds. de Grijs R., Gonzalez Delgado R.M., Kluwer: Dordrech

The future of sovereignty in multilevel governance Europe: a constructivist reading

Multilevel governance presents a depiction of contemporary structures in EU Europe as consisting of overlapping authorities and competing competencies. By focusing on emerging non-anarchical structures in the international system, hence moving beyond the conventional hierarchy/anarchy dichotomy to distinguish domestic and international arenas, this seems a radical transformation of the familiar Westphalian system and to undermine state sovereignty. Paradoxically, however, the principle of sovereignty proves to be resilient despite its alleged empirical decline. This article argues that social constructivism can explain the paradox, by considering sovereign statehood as a process-dependent institutional fact, and by showing that multilevel governance can feed into this process

Star Cluster Evolution: From young massive star clusters to old globulars

Young, massive star clusters are the most notable and significant end products of violent star-forming episodes triggered by galaxy collisions, mergers, and close encounters. The question remains, however, whether or not at least a fraction of the compact YMCs seen in abundance in extragalactic starbursts, are potentially the progenitors of globular cluster (GC)-type objects. However, because of the lack of a statistically significant sample of similar nearby objects we need to resort to either statistical arguments or to the painstaking approach of case by case studies of individual objects in more distant galaxies. Despite the difficulties inherent to addressing this issue conclusively, an ever increasing body of observational evidence lends support to the scenario that GCs, which were once thought to be the oldest building blocks of galaxies, are still forming today.Comment: 4 pages, to appear in "Globular Clusters - Guides to Galaxies", a conference held in Concepcion, Chile, March 200

The long-term survival chances of young massive star clusters

We review the long-term survival chances of young massive star clusters (YMCs), hallmarks of intense starburst episodes often associated with violent galaxy interactions. We address the key question as to whether at least some of these YMCs can be considered proto-globular clusters (GCs), in which case these would be expected to evolve into counterparts of the ubiquitous old GCs believed to be among the oldest galactic building blocks. In the absence of significant external perturbations, the key factor determining a cluster's long-term survival chances is the shape of its stellar initial mass function (IMF). It is, however, not straightforward to assess the IMF shape in unresolved extragalactic YMCs. We discuss in detail the promise of using high-resolution spectroscopy to make progress towards this goal, as well as the numerous pitfalls associated with this approach. We also discuss the latest progress in worldwide efforts to better understand the evolution of entire cluster systems, the disruption processes they are affected by, and whether we can use recently gained insights to determine the nature of at least some of the YMCs observed in extragalactic starbursts as proto-GCs. We conclude that there is an increasing body of evidence that GC formation appears to be continuing until today; their long-term evolution crucially depends on their environmental conditions, however.Comment: invited refereed review article; ChJA&A, in press; 33 pages LaTeX (2 postscript figures); requires chjaa.cls style fil

Governing urban accessibility: moving beyond transport and mobility

Access to people, goods, ideas and services is the basis of economic development in cities. The better this access, the greater the economic benefits through economies of scale, agglomeration effects and networking advantages. The way in which cities facilitate accessibility also impacts directly on other key aspects of human development, social inclusion and well-being. Accessibility is created through a complex interplay of urban form and transport systems. Thus, governing urban accessibility requires moving beyond conventional urban transport considerations linked to mobility and movement. Such a re-framing implies a far greater recognition of urban form characteristics like land use, distribution of densities and urban design, in addition to transport characteristics like infrastructures, service levels and travel speeds. A new interface between these characteristics has emerged as a result of shared mobility systems, putting additional pressure on city governments to act as system integrators. Based on a literature review, empirical insights from a global survey and the case-study cities of London, NYC and Berlin, this paper explores the institutional capacities of shifting from governing urban transport to urban accessibility. The evidence shows that there are entrenched misalignments which may impact negatively on the capacity to pair planning and policies essential for delivering better accessibility. Furthermore, it is clear that “hierarchies” and “networks” are not mutually exclusive when it comes to integrated governance of accessibility. The findings also suggest that cities may be better equipped to integrate shared mobility and consider mobility as a service than to pursue more wide-ranging metropolitan accessibility policies

Optical response of monolayer films of a metal-free sulfonamido-porphyrin

The influence of gaseous chlorine on monolayers of metal-free meso-tetra(4-amino sulfonyl)phenylporphyrin is discussed. These films exhibit characteristic intense optical absorption bands in the region 400-700 nm. Upon exposure to chlorine vapour in the concentration range 0.1-10 ppm, the Soret and Q-bands decrease in intensity and new bands at ~455 nm and ~660 nm appear. The rate of response has been measured as a function of deposition surface pressure and gas concentration. Repeated dosing experiments have shown that reversible and reproducible sensing action occurs provided that a threshold concentration is not exceeded. The recovery of the original optical spectrum can be accelerated with moderate heat treatment (60°C for 10 min). Ageing experiments have shown that the basic response of the monolayer is not effected over a time period of at least 5 months.http://www.sciencedirect.com/science/article/B6TW0-3VV0K4W-2D/1/d4a4ed344aa0216ef5d8648dd4c7102

HOW POLICY NETWORKS CAN DAMAGE DEMOCRATIC HEALTH: A CASE STUDY IN THE GOVERNMENT OF GOVERNANCE

This article examines a detailed case study of implementation networks in England using the example of the relocation of the Norfolk and Norwich hospital, which became a flagship PFI project for the Labour government after 1997. The case study illustrates the workings of the new order of multi-layered governance with both local and national networks from different policy areas interacting. However, it also sheds light on the governance debate and illustrates how in the world of new public management, powerful actors, or policy entrepreneurs, with their own agenda, still have the facility, by exercising power and authority, to shape and determine the policy outputs through implementation networks. It is argued that, whereas policy networks are normally portrayed as enriching and promoting pluralist democratic processes, implementation networks in multi-layered government can also undermine democratic accountability. Four aspects here are pertinent: (1) the degree of central government power; (2) local elite domination; (3) the fragmentation of responsibility; and (4) the dynamics of decision making which facilitates the work of policy entrepreneurs. All these factors illustrate the importance of ‘the government of governance’ in the British state