Towards Interoperability of Biomedical Ontologies

Report on Dagstuhl Seminar 07132, Schloss Dagstuhl, March 27-30 , 2007

MARGINAL VALUE OF QUALITY ATTRIBUTES FOR NATURAL (ORGANIC) BEEF

Demand and Price Analysis,

On the t-Term Rank of a Matrix

For t a positive integer, the t-term rank of a (0,1)-matrix A is defined to be the largest number of 1s in A with at most one 1 in each column and at most t 1s in each row. Thus the 1-term rank is the ordinary term rank. We generalize some basic results for the term rank to the t-term rank, including a formula for the maximum term rank over a nonempty class of (0,1)-matrices with the the same row sum and column sum vectors. We also show the surprising result that in such a class there exists a matrix which realizes all of the maximum terms ranks between 1 and t.Comment: 18 page

Cyclic Matching Sequencibility of Graphs

We define the cyclic matching sequencibility of a graph to be the largest integer $d$ such that there exists a cyclic ordering of its edges so that every $d$ consecutive edges in the cyclic ordering form a matching. We show that the cyclic matching sequencibility of $K_{2m}$ and $K_{2m+1}$ equal $m-1$

Circulant Matrices and Mathematical Juggling

Circulants form a well-studied and important class of matrices, and they arise in many algebraic and combinatorial contexts, in particular as multiplication tables of cyclic groups and as special classes of latin squares. There is also a known connection between circulants and mathematical juggling. The purpose of this note is to expound on this connection developing further some of its properties. We also formulate some problems and conjectures with some computational data supporting them

CRISPR-Cas9 Editing of Nitrate Transporter Gene, um03849, in Ustilago maydis

Ustilago maydis, the basidiomycete smut-fungus, can infect and cause tumors in corn plants. For this, mating between compatible haploid cells is important. The mating and subsequent dimorphic transition in U. maydis require starvation for nutrients such as nitrogen, in addition to pheromone-receptor interactions between compatible partners. In this research, the CRISPR-Cas9 gene-editing technique was used to create INDEL mutations (sequence insertion or deletion) in the nitrate transporter gene, um03849, in U. maydis. The gene was edited in mating compatible haploid strains 1/2 and 2/9. The phenotypes were characterized for the um03849 mutants as to growth ability, mating efficiency and pathogenesis. DNA sequence analysis confirmed isolates with 3 bp-deletion, 19 bp-deletion and 2 bp-substitution in the 1/2 mating strain, while a 3 bp-deletion and a 66 bp-insertion were found in independent isolates of the 2/9 strain. The matting assay results showed that any forms of mutation in um03849 in U. maydis didn’t affect mating with its compatible partner, as assessed by “fuzz” on charcoal media. However, the growth of mutated 1/2 strains was affected when grown in a medium with nitrate or nitrite as a source of nitrogen. With respect to host plant pathogenesis, the 1/2 strain with 2 bp substitution crossed with 2/9 WT strain showed dramatically reduced infection. Base substitution in the 1/2 strain resulted in arginine being substituted for lysine. Thus, this study suggests that the nitrate transporter affects the growth and pathogenesis of U. maydis on its host plant in a manner dependent on the 1/2 background.https://ir.library.louisville.edu/uars/1006/thumbnail.jp

UBRI Photometry of Globular Clusters in the Leo Group Galaxy NGC 3379

We present wide area UBRI photometry for globular clusters around the Leo group galaxy NGC 3379. Globular cluster candidates are selected from their B-band magnitudes and their (U-B)o vs (B-I)o colours. A colour-colour selection region was defined from photometry of the Milky Way and M31 globular cluster systems. We detect 133 globular cluster candidates which, supports previous claims of a low specific frequency for NGC 3379. The Milky Way and M31 reveal blue and red subpopulations, with (U-B)o and (B-I)o colours indicating mean metallicities similar to those expected based on previous spectroscopic work. The stellar population models of Maraston (2003) and Brocato etal (2000) are consistent with both subpopulations being old, and with metallicities of [Fe/H] \~ -1.5 and -0.6 for the blue and red subpopulations respectively. The models of Worthey (1994) do not reproduce the (U-B)o colours of the red (metal-rich) subpopulation for any modelled age. For NGC 3379 we detect a blue subpopulation with similar colours and presumably age/metallicity, to that of the Milky Way and M31 globular cluster systems. The red subpopulation is less well defined, perhaps due to increased photometric errors, but indicates a mean metallicity of [Fe/H] ~ -0.6.Comment: 12 pages, Latex, 10 figures, 1 table, submitted for publication in MNRAS, Fig. 11 available in source file or from [email protected]