On the tropical Torelli map

AbstractWe construct the moduli spaces of tropical curves and tropical principally polarized abelian varieties, working in the category of (what we call) stacky fans. We define the tropical Torelli map between these two moduli spaces and we study the fibers (tropical Torelli theorem) and the image of this map (tropical Schottky problem). Finally we determine the image of the planar tropical curves via the tropical Torelli map and we use it to give a positive answer to a question raised by Namikawa on the compactified classical Torelli map

Homogeneous colourings of graphs

summary:A proper vertex $k$-colouring of a graph $G$ is called $l$-homogeneous if the number of colours in the neigbourhood of each vertex of $G$ equals $l$. We explore basic properties (the existence and the number of used colours) of homogeneous colourings of graphs in general as well as of some specific graph families, in particular planar graphs

Understanding and Optimizing Growth and Development of California Yellowtail (Seriola dorsalis) in Aquaculture Using Physiological Tools

Physical fitness metrics were used to assess the health and development of California Yellowtail, Seriola dorsalis, in an aquaculture environment during two grow-out experiments. The first experiment sought to evaluate the effects of a common aquaculture deformity (an improperly inflated swim bladder) that has been hypothesized to impact energy allocation, growth, and development. Metrics including metabolic rate, critical swimming speed, feed conversion ratio, and growth rate, were monitored over a 32-week period in three groups of California Yellowtail: wild-caught (“wild”), healthy hatchery-reared (“inflated”), and hatchery-reared with uninflated swim bladders (“uninflated”). At the start of the grow-out period, wild fish had a significantly lower standard metabolic rate (3.08 ± 0.23 mgO2 min-1 kg-1) than both the inflated and uninflated groups (5.60 ± 0.54 and 6.45 ± 0.66 mgO2 min-1 kg-1, respectively), but this difference was not maintained over time. After a 32-week growout, inflated fish had significantly greater mass (758.6 ± 92.7 g vs. 671.1 ± 128.9 g wild, 636.1 ± 80.4 g uninflated) and girth (23.2 ± 1.1 cm vs. 21.6 ± 1.7 cm wild, 21.5 ± 1.2 cm uninflated) than the other two groups, while uninflated fish had significantly shorter BL (36.5 ± 1.9 cm vs. 38.4 ± 2.7 cm wild, 39.6 ± 2.0 cm inflated). However, the wild fish had the most efficient feed conversion (1.41 vs. 1.49 inflated, 2.08 uninflated) and needed 5.8% less feed than the inflated group, and 47.8% less feed than the uninflated group to gain equivalent mass. In addition to indicating that it wouldn’t be economical to rear yellowtail with uninflated swim bladders due to their poor growth rates and feed conversion ratios, the results of this experiment revealed that there is room for improvement in the fitness of healthy aquaculture-reared yellowtail by potentially lowering their metabolic rate and feed conversion ratios. The subsequent experiment introduced exercise (which is typically lacking in aquaculture) as a means for improvement of fitness in hatchery-reared fish, and aimed to determine if a short duration of exercise could have lasting effects on the fitness of cultured yellowtail. Fish were forced to swim continuously against a flow in custom designed raceways for two, three, or four weeks, following which, metabolic rate, growth rate, and feed conversion were assessed over a 24-week grow-out period. Results showed that the duration of exercise may have an impact on standard metabolic rate immediately following exercise, with the exercised groups showing about a 9-15% reduction in metabolic rate. However, initial metabolic differences were not retained over time. Similarly, growth rates were stimulated by exercise, potentially because their lower standard metabolic rate reflected more efficient resource use and the ability to efficiently gain weight; however, the positive growth response also weakened with time. These results indicate that exercise could play an important role in the development of this species; however, the timing (e.g. yellowtail life stage and duration of exercise) and environmental variables (e.g. temperature and flow speed) likely play important roles in optimizing the response

Endocrine And Immune Profiles Of Immature Pinnipeds

Thesis (Ph.D.) University of Alaska Fairbanks, 2011There is increasing interest in assessing the health of individuals and populations of pinnipeds found in the North Pacific, primarily due to population declines leading to conservation concerns. This study assessed the "health" of animals by quantifying hormones associated with fat mass (leptin), lipid and water metabolism (cortisol and aldosterone), and growth and metabolism (thyroxine and triiodothyronine) as well as circulating total and differential leukocyte counts and in vitro proliferation of peripheral blood mononuclear cells (PBMC). Body mass and condition are influenced by an individual's disease and nutritional state. Glucocorticoids are known to affect the immune system and may be stimulated by a multitude of factors. I hypothesized that age or body mass would influence leukocyte counts, PBMC proliferation, and hormone concentrations in Steller sea lion (Eumetopias jubatus) pups and that the response of cortisol to an acute stressor would impact immune parameters in juvenile harbor seals (Phoca vitulina ). Further, given the inherent requirements of disturbance and animal handling necessary for sampling pinnipeds, the impact of these activities on endocrine and immune profiles was assessed. Total white blood cell (WBC) counts, neutrophil counts and T cell proliferation decreased with increasing age in Steller sea lion pups. However, no relationship between body condition index and circulating concentration of hormones quantified was detected. Circulating concentrations of cortisol, thyroxine, and triiodothyronine were influenced by the rookery disturbance. However, the variation attributed to the disturbance was low and did not alter total or differential WBC counts or in vitro proliferation of PBMC. In harbor seals, cortisol and aldosterone concentrations increased following an acute stressor which resulted in a stress leukogram. Total WBC decreased driven primarily by the decrease in neutrophil counts with simultaneous increase in lymphocytes leading to an overall decrease in neutrophil to lymphocyte ratio. These findings highlight the endocrine system's influence on the immune system in immature pinnipeds

SoftKiller, a particle-level pileup removal method

Existing widely-used pileup removal approaches correct the momenta of individual jets. In this article we introduce an event-level, particle-based pileup correction procedure, SoftKiller. It removes the softest particles in an event, up to a transverse momentum threshold that is determined dynamically on an event-by-event basis. In simulations, this simple procedure appears to be reasonably robust and brings superior jet resolution performance compared to existing jet-based approaches. It is also nearly two orders of magnitude faster than methods based on jet areas.Comment: 26 pages, 16 figures (2 appendices with further checks added