Baryon Interactions in Nuclear and Hypernuclear Matter

The production and structure of Λ hypernuclei are investigated in field theoretical models. The production in coherent p+A reactions is investigated by means of a resonance model. Results of exploratory calculations for associated strangeness production are presented for proton reactions on 40Ca. The target single particle wave functions are obtained from DDRH theory with density dependent Dirac-Brueckner meson-baryon vertices. The dependence of the in-medium vertices on density is discussed.Comment: 5 pages, 2 figs, proceedings for 'HADRON SPECTROSCOPY, Tenth International Conference on Hadron Spectroscopy, Aschaffenburg, Germany 2003'. to be published in the AIP series of conference proceeding

XMM-Newton study of the ULIRG NGC 6240

A recently performed XMM-Newton observation of the ULIRG NGC 6240 clearly indicates the presence of an AGN contribution to its X-ray spectrum. In the 5.0 - 7.0 keV energy range there is a clear signature of the fluorescent Fe K lines at 6.4, 6.7 and 6.9 keV, respectively. The line strength of the 6.4 keV line cannot be produced by a thermal component. The 0.3 - 10.0 keV spectral energy distribution is characterized by the following components: (I) two hot thermal components (the starburst), (II) one direct component (heavily absorbed; AGN is hidden), (III) one reflection component (the AGN), (IV) three narrow Fe lines. The model parameters for the broad-band spectral energy distribution are consistent with the results of previously works.Comment: 2 pages incl. 2 figures, to appear in the proceedings of the "New Century of X-ray Astronomy" symposium held in Yokohama, Japan (March 6-8, 2001), eds. H. Kunieda and H. Inoue, ASP pres

The 89,000-Mr murine cytomegalovirus immediate-early protein activates gene transcription

To study trans-activation of gene expression by murine cytomegalovirus (MCMV) immediate-early (IE) proteins, the IE coding region 1 (ie1), which encodes the 89,000-Mr IE phosphoprotein (pp89), was stably introduced into L cells. A cell line was selected and characterized that efficiently expressed the authentic viral protein. The pp89 that was constitutively expressed in L cells stimulated the expression of transfected recombinant constructs containing the bacterial chloramphenicol acetyltransferase (CAT) gene under the control of viral promoters. The regulatory function of the ie1 product was confirmed by transient expression assays in which MCMV IE genes were cotransfected into L cells together with recombinant constructs of the CAT gene. For CAT activation by the ie1 product, a promoter region was required, but there was no preferential activation of a herpes simplex virus type 1 delayed-early promoter. All plasmid constructs that contained the intact coding sequences for pp89 induced gene expression in trans. The MCMV enhancer region was not essential for the expression of a functional IE gene product, and testing of the cis-regulatory activity of the MCMV enhancer revealed a low activity in L cells. Another region transcribed at IE times of infection, IE coding region 2, was unable to induce CAT expression and also did not augment the functional activity of ie1 after cotransfection

Ledoux-Convection in Protoneutron Stars --- a Clue to Supernova Nucleosynthesis?

Two-dimensional hydrodynamical simulations of the deleptonization of a newly formed neutron star were performed. Driven by negative lepton fraction and entropy gradients, convection starts near the neutrinosphere about 20-30 ms after core bounce, but moves deeper into the protoneutron star, and after about one second the whole protoneutron star is convective. The deleptonization of the star proceeds much faster than in the corresponding spherically symmetrical model because the lepton flux and the neutrino luminosities increase by up to a factor of two. The convection below the neutrinosphere raises the neutrinospheric temperatures and mean energies of the emitted neutrinos by 10-20%. This can have important implications for the supernova explosion mechanism and changes the detectable neutrino signal from the Kelvin-Helmholtz cooling of the protoneutron star. In particular, the enhanced electron neutrino flux relative to the electron antineutrino flux during the early post-bounce evolution might solve the overproduction problem of certain elements in the neutrino-heated ejecta in models of type-II supernova explosions.Comment: 17 pages, LaTeX, 8 postscript figures, uses epsf.sty. To appear in ApJ 473 (Letters), 1996 December 1

Comparison of lunar rocks and meteorites: Implications to histories of the moon and parent meteorite bodies

A number of similarities between lunar and meteoritic rocks are reported and suggest that the comparison is essential for a clear understanding of meteorites as probes of the early history of the solar systems: (1) Monomict and polymict breccias occur in lunar rocks, as well as in achondritic and chondritic meteorites, having resulted from complex and repeated impact processes. (2) Chondrules are present in lunar, as well as in a few achondritic and most chondritic meteorites. It is pointed out that because chondrules may form in several different ways and in different environments, a distinction between the different modes of origin and an estimate of their relative abundance is important if their significance as sources of information on the early history of the solar system is to be clearly understood. (3) Lithic fragments are very useful in attempts to understand the pre- and post-impact history of lunar and meteoritic breccias. They vary from little modified (relative to the apparent original texture), to partly or completely melted and recrystallized lithic fragments

‘It’s Not Going to be Suburban, It’s Going to be All Urban’: Assembling Post-suburbia in the Toronto and Chicago Regions

Urban and suburban politics are increasingly intertwined in regions that aspire to be global. Powerful actors in the Chicago and Toronto regions have mobilized regional space to brand rescaled images of the urban experience, but questions remain as to who constructs and who can access the benefits of these revised spatial identities. Local political interests have tended to be obfuscated in the regional milieu, most problematically in the spaces between the gentrified inner cities, privileged growth nodes, and the glamorized suburban subdivisions and exurban spaces beyond the city limits. This article analyses how socio-spatial changes in post-suburbanizing urban fringes contribute to the way regions are being reconfigured and reimagined. Guided by current debates at the intersection of assemblage theory and critical urban political economy, our analysis demonstrates how socio-technical infrastructures, policy mobilities and political economic relations are spatially aligned, sustained and dissolved in splintering North American agglomerations. Particular attention is paid to issues of urban transportation and connectivity in uncovering multifaceted modes of suburbanism that now underlie the monistic imagery of the globalized region. Emergent regionalized topologies and territoriality blur conventional understandings of city–suburban dichotomies in extended urban areas that are now characterized by polycentric post-suburban constellations. In terms of their substance and functionality, ‘real existing’ regions are currently re-territorialized as complex assemblages that are embedded in a neoliberalizing political economy whose politics and identities are only beginning to be revealed

Real Existing Regionalism: The Region Between Talk, Territory and Technology

In this essay, we propose the notion of real existing ‘lived’ regionalism as a rejoinder to the normative and ideological debates around new regionalism. Regional forms have shown little convergence in this age of globalized regionalization. Instead of an ideational construct or set of predictable practices, we argue that regionalism is a contested product of discourses (talk), territorial relationships (territory) and technologies (material and of power). The concept of real existing regionalism confronts the tensions between the discursive constructions and normative interventions characterizing much current regionalist debate and the territorial politics and technologies reflecting, generating and directing new state spatial strategic choices. The essay demonstrates the utility of the real existing regionalism framework through an analysis of the greenbelt, transport planning and postsuburbanization in Southern Ontario. We argue that regulatory institutions capture the Toronto region in a mix of rhetorical and technological change that complies with neither preconceived notions of regionalization nor the pessimism of total regional dysfunctionality. Rather, the lived experience of regionalization illuminates the emergent assemblages, multiplicity of everyday flows and ongoing multiscalar negotiations of diverse communities that produce the real existing region

XMM-Newton observation of the ULIRG NGC 6240: The physical nature of the complex Fe K line emission

We report on an XMM-Newton observation of the ultraluminous infrared galaxy NGC 6240. The 0.3-10 keV spectrum can be successfully modelled with: (i) three collisionally ionized plasma components with temperatures of about 0.7, 1.4, and 5.5 keV; (ii) a highly absorbed direct power-law component; and (iii) a neutral Fe K_alpha and K_beta line. We detect a significant neutral column density gradient which is correlated with the temperature of the three plasma components. Combining the XMM-Newton spectral model with the high spatial resolution Chandra image we find that the temperatures and the column densities increase towards the center. With high significance, the Fe K line complex is resolved into three distinct narrow lines: (i) the neutral Fe K_alpha line at 6.4 keV; (ii) an ionized line at about 6.7 keV; and (iii) a higher ionized line at 7.0 keV (a blend of the Fe XXVI and the Fe K_beta line). While the neutral Fe K line is most probably due to reflection from optically thick material, the Fe XXV and Fe XXVI emission arises from the highest temperature ionized plasma component. We have compared the plasma parameters of the ultraluminous infrared galaxy NGC 6240 with those found in the local starburst galaxy NGC 253. We find a striking similarity in the plasma temperatures and column density gradients, suggesting a similar underlying physical process at work in both galaxies.Comment: 8 pages including 9 figures. Accepted for publication in A&

Changing the geographies of sub/urban theory: Asian perspectives

This special issue examines the intersection of global suburbanization and Asian urbanism. The papers provide a perspective from the examination of peripheral areas in fast growing Asian metropolitan regions. From the standpoint of the peripheral space of Jakarta, Kusno challenges the prediction that the logic of capital accumulation would eventually lead to a complete urban area, leaving behind the rural. From the vantage point of Gurgaon at the edge of New Delhi, Gururani argues that many villages straddle the rural–urban divide and are embedded in property development. Describing urban villages, new towns and gated estates in peri-urban Guangzhou, Li et al. portray an assemblage of the local state, villagers, real estate developers and middle-class consumers. Investigating transit-oriented development in Shanghai, Shen and Wu reveal how the concept is borrowed by key state-owned developers to finance infrastructure development. Without proposing a concept of Asian suburbanism, the papers depict a complex urban world in Asia