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The cold dark matter model has become the leading theoretical picture for the formation of structure in the Universe. This model, together with the theory of cosmic inflation, makes a clear prediction for the initial conditions for structure formation and predicts that structures grow hierarchically through gravitational instability. Testing this model(More)
Nile perch, Lates niloticus, and Nile tilapia, Oreochromis niloticus, were originally transplanted from Lake Albert in western Uganda to the African Great Lakes, Lake Victoria and Lake Kyoga, where they are partially implicated in reduction of the fish species diversity. Lake Albert is facing multiple environmental changes, including declining fish species(More)
A., et al. (2005). Simulating the joint evolution of quasars, galaxies and their large-scale distribution. It is posted here with the permission of the publisher for your personal use. No further distribution is permitted. If your library has a subscription to this journal, you may also be able to access the published version via the library catalogue.
We discuss the design and implementation of a parallel adaptive P 3 M code, for massively parallel architectures. The code, although primarily designed for conducting gravitational simulations in a cosmological context, also includes a Smoothed Particle Hydrodynamics solver. The code is written in a combination of C, FORTRAN 77 and FORTRAN 90. The MPI-2(More)
We present a detailed investigation of a number of different approaches to modelling feedback in simulations of galaxy formation. Gas-dynamic forces are evaluated using Smoothed Particle Hydrodynamics (SPH). Star formation and supernova feedback are included using a three parameter model which determines the star formation rate (SFR) normalization, feedback(More)
We analyse the performance of twelve different implementations of Smoothed Particle Hydrodynamics (SPH) using seven tests designed to isolate key hydrodynamic elements of cosmological simulations which are known to cause the SPH algorithm problems. In order, we consider a shock tube, spherical adiabatic collapse, cooling flow model, drag, a cosmological(More)
We discuss the design and implementation of HYDRA OMP a parallel implementation of the Smoothed Particle Hydrodynamics–Adaptive P 3 M (SPH-AP 3 M) code HYDRA. The code is designed primarily for conducting cosmological hydrodynamic simulations and is written in Fortran77+OpenMP. A number of optimizations for RISC processors and SMP-NUMA architectures have(More)
Aims. We examine radial and vertical metallicity gradients using a suite of disk galaxy hydrodynamical simulations, supplemented with two classic chemical evolution approaches. We determine the rate of change of gradient slope and reconcile the differences existing between extant models and observations within the canonical " inside-out " disk growth(More)
We examine the effects of galaxy outflows on the formation of dwarf galaxies in numerical simulations of the high-redshift Universe. Using a Smoothed Particle Hydrodynamic code, we conduct two detailed simulations of a (5.2 Mpc/h) 3 comoving volume of the Universe. In both simulations we implement simple, well-motivated models of galaxy identification and(More)