The Impact of Acid Deposition on Groundwater: A Review

Theoretical mechanisms and empirical evidence of the potential acidification of groundwater under forested soils in Europe have been reviewed in order to provide a starting point for an assessment of the acidification of groundwater in the scope of the Acid Rain study carried out at IIASA. Basic characteristics of forested soil-water systems are presented as a background to a discussion of the transport and the release and retention of elements. The report relates the impact of acid deposition of groundwater to the pedology, the climatic regime and the geohydrology of the region. Some approaches of modeling the problem are reviewed, including dynamic models and sensitivity analysis. A procedure for assessing the impact of various energy pathways on the potential for acidification of groundwater is outlined. The method proposed combines a regional ranking of the static sensitivity with a dynamic simulation of the impact of acid deposition on the chemistry of top soil

The Properties of Satellite Galaxies in External Systems. I. Morphology and Structural Parameters

We present the first results of an ongoing project to study the morphological, kinematical, dynamical, and chemical properties of satellite galaxies of external giant spiral galaxies. The sample of objects has been selected from the catalogue by Zaritsky et al. (1997). The paper analyzes the morphology and structural parameters of a subsample of 60 such objects. The satellites span a great variety of morphologies and surface brightness profiles. About two thirds of the sample are spirals and irregulars, the remaining third being early-types. Some cases showing interaction between pairs of satellites are presented and briefly discussed.Comment: Accepted for publication in Astrophys. Journal Supp. Se

Viking '75 spacecraft design and test summary. Volume 1: Lander design

The Viking Mars program is summarized. The design of the Viking lander spacecraft is described

Seeing Galaxies Through Thick & Thin. III. HST Imaging of the Dust in Backlit Spiral Galaxies

We present analysis of WFPC2 imaging of two spiral galaxies partially backlit by E/S0 systems in the pairs AM1316-241 and AM0500-620, and the spiral foreground system in NGC 1275. Images in B and I are used to determine the reddening curve of in these systems. The spiral component of AM1316-241 shows dust strongly concentrated in discrete arms, with a reddening law very close to the Milky Way mean. The dust distribution is scale-free between about 100 pc and the arm scale. The spiral in AM0500-620 shows dust concentrated in arms and interarm spurs, with measurable interarm extinction as well. Although its dust properties are less well-determined, we find evidence for a steeper extinction law here. The shape of the reddening law suggests that, at least in AM1316-241, we have resolved most of the dust structure. In AM0500-620, the slope of the fractal perimeter-scale relation steepens systematically from low to high extinction. In AM1316-241, we cannot determine a unique fractal dimension from the defining area-perimeter relation, so the projected dust distribution is best defined as fractal-like. In neither galaxy do we see regions even on single-pixel scales in spiral arms with AB > 2.5. The measurements in NGC 1275 are compromised by our lack of independent knowledge of the foreground system's light distribution, but masked sampling of the absorption suggests an effective reddening curve much flatter than the Milky Way mean (perhaps indicating that the foreground system has been affected by immersion in the hot intracluster gas).Comment: Astronomical Journal, in press. 13 figures. Full-size PostScript figures available at http://www.astr.ua.edu/preprints/kee

Simulation and Evaluation of Zonal Electricity Market Designs

Zonal pricing with countertrading (a market-based redispatch) gives arbitrage opportunities to the power producers located in the export-constrained nodes. They can increase their profit by increasing the output in the day-ahead market and decrease it in the real-time market (the inc-dec game). We show that this leads to large inefficiencies in a standard zonal market. We also show how the inefficiencies can be significantly mitigated by changing the design of the real-time market. We consider a two-stage game with oligopoly producers, wind-power shocks and real-time shocks. The game is formulated as a two-stage stochastic equilibrium problem with equilibrium constraints (EPEC), which we recast into a two-stage stochastic Mixed-Integer Bilinear Program (MIBLP). We present numerical results for a six-node and the IEEE 24-node system

Changing Academic Medicine: Strategies Used by Academic Leaders of Integrative Medicine—A Qualitative Study

In Western countries, complementary and alternative medicine (CAM) is more and more provided by practitioners and family doctors. To base this reality of health care provision on an evidence-base, academic medicine needs to be included in the development. In the study we aimed to gain information on a structured approach to include CAM in academic health centers. We conducted a semistructured interview study with leading experts of integrative medicine to analyze strategies of existing academic institutions of integrative medicine. The study sample consisted of a purposive sample of ten leaders that have successfully integrated CAM into medical schools in the USA, Great Britain, and Germany and the Director of the National Center for Alternative and Complementary Medicine. Analysis was based on content analysis. The prerequisite to foster change in academic medicine was a strong educational and professional background in academic medicine and research methodologies. With such a skill set, the interviewees identified a series of strategies to align themselves with colleagues from conventional medicine, such as creating common goals, networking, and establishing well-functioning research teams. In addition, there must be a vision of what should be needed to be at the center of all efforts in order to implement successful change

Modelling the effects of climate on long-term patterns of dissolved organic carbon concentrations in the surface waters of a boreal catchment

International audienceDissolved organic carbon concentrations ([DOC]) in surface waters are increasing in many regions of Europe and North America. These increases are likely driven by a combination of changing climate, recovery from acidification and change in severity of winter storms in coastal areas. INCA-C, a process-based model of climate effects on surface water [DOC], was used to explore the mechanisms by which changing climate controls seasonal to inter-annual patterns of [DOC] in the lake and outflow stream of a small Finnish catchment between 1990 and 2003. Both production in the catchment and mineralization in the lake controlled [DOC] in the lake. Concentrations in the catchment outflow were controlled by rates of DOC production in the surrounding organic soils. The INCA-C simulation results were compared to those obtained using artificial neural networks (ANN). In general, "black box" ANN models provide better fits to observed data but process-based models can identify the mechanism responsible for the observed pattern. A statistically significant increase was observed in both INCA-C modelled and measured annual average [DOC] in the lake. This suggests that some of the observed increase in surface water [DOC] is caused by climate-related processes operating in the lake and catchment. However, a full understanding of surface water [DOC] dynamics can only come from catchment-scale process-based models linking the effects of changing climate and deposition on aquatic and terrestrial environments

Substructure around M31 : Evolution and Effects

We investigate the evolution of a population of 100 dark matter satellites orbiting in the gravitational potential of a realistic model of M31. We find that after 10 Gyr, seven subhalos are completely disrupted by the tidal field of the host galaxy. The remaining satellites suffer heavy mass loss and overall, 75% of the mass initially in the subhalo system is tidally stripped. Not surprisingly, satellites with pericentric radius less than 30 kpc suffer the greatest stripping and leave a complex structure of tails and streams of debris around the host galaxy. Assuming that the most bound particles in each subhalo are kinematic tracers of stars, we find that the halo stellar population resulting from the tidal debris follows an r^{-3.5} density profile at large radii. We construct B-band photometric maps of stars coming from disrupted satellites and find conspicuous features similar both in morphology and brightness to the observed Giant Stream around Andromeda. An assumed star formation efficiency of 5-10% in the simulated satellite galaxies results in good agreement with the number of M31 satellites, the V-band surface brightness distribution, and the brightness of the Giant Stream. During the first 5 Gyr, the bombardment of the satellites heats and thickens the disk by a small amount. At about 5 Gyr, satellite interations induce the formation of a strong bar which, in turn, leads to a significant increase in the velocity dispersion of the disk.Comment: 45 pages, 18 figures. To be submitted to the Astrophysical Journal, version 2.0 : scale height value corrected, references added, and some figures have been modifie