Automated pebble mosaic stylization of images

Digital mosaics have usually used regular tiles, simulating the historical "tessellated" mosaics. In this paper, we present a method for synthesizing pebble mosaics, a historical mosaic style in which the tiles are rounded pebbles. We address both the tiling problem, where pebbles are distributed over the image plane so as to approximate the input image content, and the problem of geometry, creating a smooth rounded shape for each pebble. We adapt SLIC, simple linear iterative clustering, to obtain elongated tiles conforming to image content, and smooth the resulting irregular shapes into shapes resembling pebble cross-sections. Then, we create an interior and exterior contour for each pebble and solve a Laplace equation over the region between them to obtain height-field geometry. The resulting pebble set approximates the input image while presenting full geometry that can be rendered and textured for a highly detailed representation of a pebble mosaic

Field and model assessment of the ecological impacts of redesigning compensation flow releases

Rivers around the world have been regulated for a variety of reasons. Historically the flows released from these reservoirs have been set with minimal attention to ecology. The aim of this study was to use both field and modelling techniques to assess the ecological implications for altering compensation flow regimes in upland millstone grit catchments. A simple paired-catchment approach was chosen. The study catchments used were the regulated Rivelin and Loxley (tributaries of the River Don), and the unregulated Hipper. Before the 1st of April 2004， the steady state compensation releases from the Rivelin and Loxley were set at 2,6 Thousand Cubic Metres per Day (TCMD) and 28 TCMD respectively. After the Ր՛ of April 2004 the compensation flows were altered on the Rivelin and Loxley to 8.6 TCMD and 22 TCMD. This study used three broad scales of enquiry: macroinvertebrates; fisheries and modelling. Detailed macroinvertebrate surveys were conducted over a four year period (2002-2005), with samples taken in the spring, summer and autumn of each of those years. Surber samples were taken, along with associated environmental variables. Data analysis was conducted using both univariate and multivariate techniques. The invertebrate results showed that the role of flow variability is key within both of the regulated systems. The influence of flow variability is different on each of the study rivers, and the influence changes due to the alteration in compensation flows. Fisheries surveys were also conducted over this four year study period (2002-2005). Nine sites were surveyed yearly on the Rivelin and Loxley; and three on the Hipper. The fish populations in each of the rivers are dominated by brown trout (Salmo trutta). The importance of the interaction of reach scale morphology and discharge was evident in the fisheries populations with the Rivelin having similar observed densities of brown trout as the Loxley. Altering the compensation flow regimes appears to lead to an increase in the growth rate of older trout within the Rivelin.A two-dimensional hydraulic model was used to simulate the distributions of depths and velocities on four study reaches (two on the Rivelin; two on the Loxley). The model was calibrated to three separate calibration data sets. Subsequently, steady state simulations were conduced for the pre and post change compensation flows in each of the reaches. This output was subsequently linked to a fuzzy-logic based habitat model in order to generate predictions of available habitat. Predictions of available habitat were generated for four life stages of brown trout and for functional feeding groups of macroinvertebrates

Black Holes in 4 Nearby Radio Galaxies

We study the velocity dispersion profiles of the nuclei of NGC 1326, 2685, 5273 and 5838 in the CO first overtone band. There is evidence for a black hole (BH) in NGC 1326 and 5838. Gas is seen flowing out of the nuclear region of NGC 5273. We put upper limits on the nuclear BHs responsible for its activity and that of NGC 2685.Comment: to appear in ApS

Infrared Spectroscopy of Nearby Radio Active Elliptical Galaxies

In preparation for a study of their circumnuclear gas we have surveyed 60% of a complete sample of elliptical galaxies within 75 Mpc that are radio sources. Some 20% of our nuclear spectra have infrared emission lines, mostly Paschen lines, Brackett γ, and [Fe II]. We consider the influence of radio power and black hole mass in relation to the spectra. Access to the spectra is provided here as a community resource

The integrins of the urochordate Ciona intestinalis provide novel insights into the molecular evolution of the vertebrate integrin family

BACKGROUND: Integrins are a functionally significant family of metazoan cell surface adhesion receptors. The receptors are dimers composed of an alpha and a beta chain. Vertebrate genomes encode an expanded set of integrin alpha and beta chains in comparison with protostomes such as drosophila or the nematode worm. The publication of the genome of a basal chordate, Ciona intestinalis, provides a unique opportunity to gain further insight into how and when the expanded integrin supergene family found in vertebrates evolved. RESULTS: The Ciona genome encodes eleven α and five β chain genes that are highly homologous to their vertebrate homologues. Eight of the α chains contain an A-domain that lacks the short alpha helical region present in the collagen-binding vertebrate alpha chains. Phylogenetic analyses indicate the eight A-domain containing α chains cluster to form an ascidian-specific clade that is related to but, distinct from, the vertebrate A-domain clade. Two Ciona α chains cluster in laminin-binding clade and the remaining chain clusters in the clade that binds the RGD tripeptide sequence. Of the five Ciona β chains, three form an ascidian-specific clade, one clusters in the vertebrate β1 clade and the remaining Ciona chain is the orthologue of the vertebrate β4 chain. CONCLUSION: The Ciona repertoire of integrin genes provides new insight into the basic set of these receptors available at the beginning of vertebrate evolution. The ascidian and vertebrate α chain A-domain clades originated from a common precursor but radiated separately in each lineage. It would appear that the acquisition of collagen binding capabilities occurred in the chordate lineage after the divergence of ascidians

The Protean Challenge of Game Collections at Academic Libraries

The rise of game development and game studies on university campuses prompts academic libraries to consider how to support teaching and research in this area. This article examines current issues and challenges in the development of game collections at academic libraries. The gaming ecosystem has become more complex and libraries may need to move beyond collections largely based on console video games. This article will advance the discussion by considering emerging issues to support access to the full range of games. The article will use examples from Carleton University Library, Ottawa, which has been developing a game collection since 2008