University of Victoria

About: University of Victoria is a education organization based out in Victoria, British Columbia, Canada. It is known for research contribution in the topics: Population & Galaxy. The organization has 14994 authors who have published 41051 publications receiving 1447972 citations. The organization is also known as: Victoria College.

Two Strikes Against Perfect Phylogeny

Abstract: One of the major efforts in molecular biology is the computation of phytogenies for species sets. A longstanding open problem in this area is called the Perfect Phylogeny problem. For almost two decades the complexity of this problem remained open, with progress limited to polynomial time algorithms for a few special cases, and many relaxations of the problem shown to be NP-Complete. From an applications point of view, the problem is of interest both in its general form, where the number of characters may vary, and in its fixed-parameter form. The Perfect Phylogeny problem has been shown to be equivalent to the problem of triangulating colored graphs[30]. It has also been shown recently that for a given fixed number of characters the yes-instances have bounded treewidth[45], opening the possibility of applying methodologies for bounded treewidth to the fixed-parameter form of the problem. We show that the Perfect Phylogeny problem is difficult in two different ways. We show that the general problem is NP-Complete, and we show that the various finite-state approaches for bounded treewidth cannot be applied to the fixed-parameter forms of the problem.

The Detection and Attribution Model Intercomparison Project (DAMIP v1.0)contribution to CMIP6

Abstract: . Detection and attribution (DA to contribute to the estimation of how historical emissions have altered and are altering contemporary climate risk; and to facilitate improved observationally constrained projections of future climate change. D&A studies typically require unforced control simulations and historical simulations including all major anthropogenic and natural forcings. Such simulations will be carried out as part of the DECK and the CMIP6 historical simulation. In addition D&A studies require simulations covering the historical period driven by individual forcings or subsets of forcings only: such simulations are proposed here. Key novel features of the experimental design presented here include firstly new historical simulations with aerosols-only, stratospheric-ozone-only, CO2-only, solar-only, and volcanic-only forcing, facilitating an improved estimation of the climate response to individual forcing, secondly future single forcing experiments, allowing observationally constrained projections of future climate change, and thirdly an experimental design which allows models with and without coupled atmospheric chemistry to be compared on an equal footing.

Insight into water oxidation by mononuclear polypyridyl Ru catalysts.

Abstract: A family of compounds based on the mononuclear coordination complex [Ru(tpy)(bpy)(OH2)]2+ (1b; tpy = 2,2′:6′,2′′-terpyridine, bpy = 2,2′-bipyridine) are shown to be competent catalysts in the Ce(IV)-driven oxidation of water in acidic media. The systematic installation of electron-withdrawing (e.g., −Cl, −COOH) and −donating (e.g., −OMe) groups at various positions about the periphery of the polypyridyl framework offers insight into how electronic parameters affect the properties of water oxidation catalysts. It is observed, in general, that electron-withdrawing groups (EWGs) on the bpy ligands suppress catalytic activity (kobs) and enhance catalytic turnover numbers (TONs); conversely, the presence of electron-donating groups (EDGs) accelerate catalytic rates while decreasing catalyst stability. We found that 2,2′-bipyridine N,N′-dioxide is produced when 1b is subject to excess Ce(IV) in acidic media, which suggests that dissociation of the bpy ligand is a source of catalyst deactivation and/or decomposi...

The Pareto law of incomes—an explanation and an extension

Abstract: A stochastic model for the generation of observed income distributions is used to provide an explanation for the Pareto law of incomes. Analysis of the model also yields a prediction of Paretian (power law) behaviour in the lower tail of the distribution and this is shown to occur in a number of empirical distributions. A tractable four-parameter distribution is derived, and shown to fit extremely well to a number of different empirical income distributions.