Modelling end-pumped solid state lasers

The operation dynamics of end-pumped solid-state lasers are investigated by means of a spatially resolved numerical rate-equation model and a time-dependent analytical thermal model. The rate-equation model allows the optimization of parameters such as the output coupler transmission and gain medium length, with the aim of improving the laser output performance. The time-dependent analytical thermal model is able to predict the temperature and the corresponding induced thermal stresses on the pump face of quasi-continuous wave (qcw) end-pumped laser rods. Both models are found to be in very good agreement with experimental results

Bulge Globular Clusters in Spiral Galaxies

There is now strong evidence that the metal-rich globular clusters (GC) near the center of our Galaxy are associated with the Galactic bulge rather than the disk as previously thought. Here we extend the concept of bulge GCs to the GC systems of nearby spiral galaxies. In particular, the kinematic and metallicity properties of the GC systems favor a bulge rather than a disk origin. The number of metal-rich GCs normalized by the bulge luminosity is roughly constant (i.e. bulge S_N ~ 1) in nearby spirals, and this value is similar to that for field ellipticals when only the red (metal--rich) GCs are considered. We argue that the metallicity distributions of GCs in spiral and elliptical galaxies are remarkably similar, and that they obey the same correlation of mean GC metallicity with host galaxy mass. We further suggest that the metal-rich GCs in spirals are the direct analogs of the red GCs seen in ellipticals. The formation of a bulge/spheroidal stellar system is accompanied by the formation of metal-rich GCs. The similarities between GC systems in spiral and elliptical galaxies appear to be greater than the differences.Comment: 5 pages, Latex, 2 figures, 1 table, Accepted for publication in ApJ Letter

The aphids (Homoptera: Aphididae) of British Columbia. 11. Further additions

Ten species of aphids and new host records are added to the taxonomic list of the aphids of British Columbia

The Connection between Globular Cluster Systems and the Host Galaxies

A large number of early type galaxies are now known to possess blue and red subpopulations of globular clusters. We have compiled a database of 28 such galaxies exhibiting bimodal globular cluster colour distributions. After converting to a common V-I colour system, we investigate correlations between the mean colour of the blue and red subpopulations with galaxy velocity dispersion. We support previous claims that the mean colour of the blue globular clusters are unrelated to their host galaxy. They must have formed rather independently of the galaxy potential they now inhabit. The mean blue colour is similar to that for halo globular clusters in our Galaxy and M31. The red globular clusters, on the other hand, reveal a strong correlation with galaxy velocity dispersion. Futhermore, in well-studied galaxies the red subpopulation has similar, and possibly identical, colours to the galaxy halo stars. Our results indicate an intimate link between the red globular clusters and the host galaxy; they share a common formation history. A natural explanation for these trends would be the formation of the red globular clusters during galaxy collapse.Comment: 6 pages, Latex, 3 figures, 1 table, submitted to MNRA

Quantum diffusion on a cyclic one dimensional lattice

The quantum diffusion of a particle in an initially localized state on a cyclic lattice with N sites is studied. Diffusion and reconstruction time are calculated. Strong differences are found for even or odd number of sites and the limit N->infinit is studied. The predictions of the model could be tested with micro - and nanotechnology devices.Comment: 17 pages, 5 figure

The aphids (Homoptera: Aphididae) of British Columbia. 16. Further additions

Six species of aphids and new host records are added to the taxonomic list of the aphids of British Columbia

The aphids (Homoptera: Aphididae) of British Columbia 8. Further additions

Twenty-four species of aphids and new host records are added to the taxonomic list of the aphids of British Columbia

The aphids (Homoptera: Aphididae) of British Columbia 13. further additions

Eleven species of aphids and new host records are added to the taxonomic list of the aphids of British Columbia