The Shape of Dark Matter Haloes IV. The Structure of Stellar Discs in Edge-on Galaxies

We present optical and near-infrared archival observations of eight edge-on galaxies. These observations are used to model the stellar content of each galaxy using the FitSKIRT software package. Using FitSKIRT, we can self-consistently model a galaxy in each band simultaneously while treating for dust. This allows us to accurately measure both the scale length and scale height of the stellar disc, plus the shape parameters of the bulge. By combining this data with the previously reported integrated magnitudes of each galaxy, we can infer their true luminosities. We have successfully modelled seven out of the eight galaxies in our sample. We find that stellar discs can be modelled correctly, but have not been able to model the stellar bulge reliably. Our sample consists for the most part of slow rotating galaxies, and we find that the average dust layer is much thicker than what is reported for faster rotating galaxies.Comment: Accepted for publication by Monthly Notices RAS. Hi-res. version available at www.astro.rug.nl/~vdkruit/Petersetal-IV.pd

The intrinsic strangeness and charm of the nucleon using improved staggered fermions

We calculate the intrinsic strangeness of the nucleon, - , using the MILC library of improved staggered gauge configurations using the Asqtad and HISQ actions. Additionally, we present a preliminary calculation of the intrinsic charm of the nucleon using the HISQ action with dynamical charm. The calculation is done with a method which incorporates features of both commonly-used methods, the direct evaluation of the three-point function and the application of the Feynman- Hellman theorem. We present an improvement on this method that further reduces the statistical error, and check the result from this hybrid method against the other two methods and find that they are consistent. The values for and found here, together with perturbative results for heavy quarks, show that dark matter scattering through Higgs-like exchange receives roughly equal contributions from all heavy quark flavors.Comment: 17 pages, 14 figure

Some General Regularities of Techno-Economic Evolution

One of the most exciting phenomena of the modern world is the fundamentally homogeneous direction of the overall techno-economic development trajectory in practically all regions of the world. The existing economic systems in different countries are collapsing one after another under the pressure of an expanding industrial culture and are becoming drawn into the international division of labor. Simultaneously, their economic development is influenced by the general regularities of the world techno-economic system, the rhythm of which is set by the industrially developed countries. These general regularities of long-term techno-economic development, invariant under different sociopolitical systems, are the subject of this chapter

More pieces of the puzzle: Chemistry and substructures in the Galactic thick disk

We present a study of the chemical abundances of Solar neighbourhood stars associated to dynamical structures in the Milky Way's (thick) disk. These stars were identified as overdensity in the eccentricity range 0.3< ecc < 0.5 in the Copenhagen-Geneva Survey by Helmi et al. (2006). We find that the stars with these dynamical characteristics do not constitute a homogeneous population. A relatively sharp transition in dynamical and chemical properties appears to occur at a metallicity of [Fe/H] ~ -0.4. Stars with [Fe/H] > -0.4 have mostly lower eccentricities, smaller vertical velocity dispersions, are alpha-enhanced and define a rather narrow sequence in [alpha/Fe] vs [Fe/H], clearly distinct from that of the thin disk. Stars with [Fe/H] < -0.4 have a range of eccentricities, are hotter vertically, and depict a larger spread in [alpha/Fe]. We have also found tentative evidence of substructure possibly associated to the disruption of a metal-rich star cluster. The differences between these populations of stars is also present in e.g. [Zn/Fe], [Ni/Fe] and [SmII/Fe], suggesting a real physical distinction.Comment: Astrophysical Journal in press. 5 pages, 4 figure

An HI census of Loose Groups of Galaxies

We present results from our Parkes Multibeam HI survey of 3 loose groups of galaxies that are analogous to the Local Group. This is a survey of groups containing only spiral galaxies with mean separations of a few hundred kpc, and total areas of approximately 1 sq. Mpc; groups similar to our own Local Group. We present a census of the HI-rich objects in these groups down to an M(HI), 1-sigma sensitivity ~7x10^5 M(sun), as well as the detailed properties of these detections from follow-up Compact Array observations. We found 7 new HI-rich members in the 3 groups, all of which have stellar counterparts and are, therefore, typical dwarf galaxies. The ratio of low-mass to high-mass gas-rich galaxies in these groups is less than in the Local Group meaning that the ``missing satellite'' problem is not unique. No high-velocity cloud analogs were found in any of the groups. If HVCs in these groups are the same as in the Local Group, this implies that HVCs must be located within ~300-400 kpc of the Milky Way.Comment: 6 pages, to appear in the ASP proceedings of IAU Symposium 217, "Recycling intergalactic and interstellar matter", eds. Pierre-Alain Duc, Jonathan Braine, Elias Brink

Project for the analysis of technology transfer Quarterly report, 1 Oct. - 31 Dec. 1969

Analysis of Tech Brief-Technical Support Package progra

Peatlands and the carbon cycle: from local processes to global implications - a synthesis

Peatlands cover only 3% of the Earth's land surface but boreal and subarctic peatlands store about 15-30% of the world's soil carbon ( C) as peat. Despite their potential for large positive feedbacks to the climate system through sequestration and emission of greenhouse gases, peatlands are not explicitly included in global climate models and therefore in predictions of future climate change. In April 2007 a symposium was held in Wageningen, the Netherlands, to advance our understanding of peatland C cycling. This paper synthesizes the main findings of the symposium, focusing on (i) small-scale processes, (ii) C fluxes at the landscape scale, and (iii) peatlands in the context of climate change. The main drivers controlling most are related to some aspects of hydrology. Despite high spatial and annual variability in Net Ecosystem Exchange ( NEE), the differences in cumulative annual NEE are more a function of broad scale geographic location and physical setting than internal factors, suggesting the existence of strong feedbacks. In contrast, trace gas emissions seem mainly controlled by local factors. Key uncertainties remain concerning the existence of perturbation thresholds, the relative strengths of the CO2 and CH4 feedback, the links among peatland surface climate, hydrology, ecosystem structure and function, and trace gas biogeochemistry as well as the similarity of process rates across peatland types and climatic zones. Progress on these research areas can only be realized by stronger co-operation between disciplines that address different spatial and temporal scales

Plain packaging: a time for action

It is almost thirty years since a senior vice president of marketing at British American Tobacco forewarned that tobacco products may eventually have to sell themselves through the pack.1 His prediction has now come true for countries with wide-ranging marketing controls. The tobacco industry has shown remarkable resilience and marketing ingenuity to continue promoting its wares, and the pack has become the focus of its efforts