The role of the Interstellar Medium in Galaxy Formation Simulations

There is a strong connection between the formation of a disk galaxy and the properties of the interstellar medium (ISM). Theoretical work has typically either focused on the cosmological buildup of a galaxy with a relatively crude model for the gas physics, or examined local processes in the ISM and ignored the global evolution of the galaxy itself. Here, I briefly review what has been learned from both of these approaches, and what can be done to bridge the gap between them. I argue that cosmological simulations need to learn from observational and theoretical work on local ISM properties and adopt more sophisticated models for the processes that they cannot resolve. Since the ISM is still incompletely understood, there are a number of reasonable approaches for these "subgrid" models, and I will discuss the strengths and limitations of each.Comment: 10 pages, 4 figures, appeared in the proceedings of the CRAL-Conference Series I "Chemodynamics: from first stars to local galaxies", Lyon 10-14 July 2006, France, Eds. Emsellem, Wozniak, Massacrier, Gonzalez, Devriendt, Champavert, EAS Publications Serie

The impact of childhood health conditions: examining experiences of the family around the child

Background: Research has examined family functioning in relation to childhood chronic conditions; some findings suggest a detrimental impact of illness on functioning, others suggest no impact or instances of improved functioning. This review collated qualitative data, to understand the factors facilitating healthy functioning. Method: Four electronic databases were searched: Web of Science, Medline, CINAHL and Psych INFO and ten papers were identified. Results: A meta-ethnographic synthesis showed that families encounter a variety of potential stressors, such as distress following diagnosis. They manage these through various resources including contact with health services. The synthesis highlighted an appraisal process mediating the perception of stressors and resources. This process occurs on interconnected levels (individual, family and wider system) and it is this, rather than the specific stressors or resources encountered, that impacts functioning. Discussion: The challenges commonly encountered by families managing childhood chronic conditions can be experienced very differently depending on their systems of appraisal. This has clinical implications as health services should not only offer holistic support to families but regularly review how this support is perceived. Research could be extended to investigate which factors promote a more positive appraisal of challenging situations

Achieving Extreme Resolution in Numerical Cosmology Using Adaptive Mesh Refinement: Resolving Primordial Star Formation

As an entry for the 2001 Gordon Bell Award in the "special" category, we describe our 3-d, hybrid, adaptive mesh refinement (AMR) code, Enzo, designed for high-resolution, multiphysics, cosmological structure formation simulations. Our parallel implementation places no limit on the depth or complexity of the adaptive grid hierarchy, allowing us to achieve unprecedented spatial and temporal dynamic range. We report on a simulation of primordial star formation which develops over 8000 subgrids at 34 levels of refinement to achieve a local refinement of a factor of 10^12 in space and time. This allows us to resolve the properties of the first stars which form in the universe assuming standard physics and a standard cosmological model. Achieving extreme resolution requires the use of 128-bit extended precision arithmetic (EPA) to accurately specify the subgrid positions. We describe our EPA AMR implementation on the IBM SP2 Blue Horizon system at the San Diego Supercomputer Center.Comment: 23 pages, 5 figures. Peer reviewed technical paper accepted to the proceedings of Supercomputing 2001. This entry was a Gordon Bell Prize finalist. For more information visit http://www.TomAbel.com/GB