How to improve Drenchrite

Understanding the strengths and weaknesses of DrenchRite and how it relates to faecal egg count reduction tests (FECRT) will lead to clearer interpretation of DrenchRite results and a better perspective on both tests. In previous studies efficacy was estimated for worms resistant to BZ, LEV and BZILEV combinations by FECRT, DrenchRite and post mortem worm counts. Correlations of in vivo efficacy with FECRT determined by them were: Trichostrongylus colubriformis 88%, Ostertagia circumcincta 56% and Haemonchus contortus 69%. The low correlation for O. circumcincta was associated with the variability in estimating species composition when O. circumcincta was present at low levels. Correlations of DrenchRite with in vivo efficacy were: O. circumcincta 87%, T. colubriformis 82% and H. contortus 80%. The correlation between resistance determined by Larval Development Assay (LDA) and FECRT was not high at 61% (averaged over drugs and species). Similar data for Macrocyclic Lactones (ML) resistant worms are not yet available. Previous studies have shown for some LDA systems that eggs are more likely to be inhibited in development to L3s early (2-3 weeks post infection (PI)) and late (beyond 10 weeks PI) after infection and are most resilient to the effect of drugs at about 7 weeks PI. No systematic changes in DrenchRite results were observed over age of worm infection when tested weekly for 2 to 14 week old worms. Large bowel worms of sheep have not generally been examined under LDA conditions so a study was undertaken to determine the LD50s of susceptible Oesophagostomum columbianum (nodule worm) and Chabertia ovina (large mouthed bowel worm) on DrenchRite plates. LD50s for BZ and LEV were approximately 0.04 and 0.8 uM respectively for both worms. For the ML O. columbianum had a much higher LD50 (45 nM) than C. ovina (8 nM). In relation to the other common sheep worms, development characteristics of C. ovina in LDA is like H. contortus while O. columbianum is more like O. circumcincta. Both large bowel worms were very sensitive to BZILEV combinations, with LD50s 4 to 8 fold lower than those observed for H. contortus and O. circumcincta

The structure of blocks with a Klein four defect group

We prove Erdmann’s conjecture [16] stating that every block with a Klein four defect group has a simple module with trivial source, and deduce from this that Puig’s finiteness conjecture holds for source algebras of blocks with a Klein four defect group. The proof uses the classification of finite simple groups

The Lee-Yang and P\'olya-Schur Programs. I. Linear Operators Preserving Stability

In 1952 Lee and Yang proposed the program of analyzing phase transitions in terms of zeros of partition functions. Linear operators preserving non-vanishing properties are essential in this program and various contexts in complex analysis, probability theory, combinatorics, and matrix theory. We characterize all linear operators on finite or infinite-dimensional spaces of multivariate polynomials preserving the property of being non-vanishing whenever the variables are in prescribed open circular domains. In particular, this solves the higher dimensional counterpart of a long-standing classification problem originating from classical works of Hermite, Laguerre, Hurwitz and P\'olya-Schur on univariate polynomials with such properties.Comment: Final version, to appear in Inventiones Mathematicae; 27 pages, no figures, LaTeX2

Plant functional and taxonomic diversity in European grasslands along climatic gradients

Aim: European grassland communities are highly diverse, but patterns and drivers of their continental-scale diversity remain elusive. This study analyses taxonomic and functional richness in European grasslands along continental-scale temperature and precipitation gradients. Location: Europe. Methods: We quantified functional and taxonomic richness of 55,748 vegetation plots. Six plant traits, related to resource acquisition and conservation, were analysed to describe plant community functional composition. Using a null-model approach we derived functional richness effect sizes that indicate higher or lower diversity than expected given the taxonomic richness. We assessed the variation in absolute functional and taxonomic richness and in functional richness effect sizes along gradients of minimum temperature, temperature range, annual precipitation, and precipitation seasonality using a multiple general additive modelling approach. Results: Functional and taxonomic richness was high at intermediate minimum temperatures and wide temperature ranges. Functional and taxonomic richness was low in correspondence with low minimum temperatures or narrow temperature ranges. Functional richness increased and taxonomic richness decreased at higher minimum temperatures and wide annual temperature ranges. Both functional and taxonomic richness decreased with increasing precipitation seasonality and showed a small increase at intermediate annual precipitation. Overall, effect sizes of functional richness were small. However, effect sizes indicated trait divergence at extremely low minimum temperatures and at low annual precipitation with extreme precipitation seasonality. Conclusions: Functional and taxonomic richness of European grassland communities vary considerably over temperature and precipitation gradients. Overall, they follow similar patterns over the climate gradients, except at high minimum temperatures and wide temperature ranges, where functional richness increases and taxonomic richness decreases. This contrasting pattern may trigger new ideas for studies that target specific hypotheses focused on community assembly processes. And though effect sizes were small, they indicate that it may be important to consider climate seasonality in plant diversity studies

How to improve Drenchrite

Understanding the strengths and weaknesses of DrenchRite and how it relates to faecal egg count reduction tests (FECRT) will lead to clearer interpretation of DrenchRite results and a better perspective on both tests. In previous studies efficacy was estimated for worms resistant to BZ, LEV and BZILEV combinations by FECRT, DrenchRite and post mortem worm counts. Correlations of in vivo efficacy with FECRT determined by them were: Trichostrongylus colubriformis 88%, Ostertagia circumcincta 56% and Haemonchus contortus 69%. The low correlation for O. circumcincta was associated with the variability in estimating species composition when O. circumcincta was present at low levels. Correlations of DrenchRite with in vivo efficacy were: O. circumcincta 87%, T. colubriformis 82% and H. contortus 80%. The correlation between resistance determined by Larval Development Assay (LDA) and FECRT was not high at 61% (averaged over drugs and species). Similar data for Macrocyclic Lactones (ML) resistant worms are not yet available. Previous studies have shown for some LDA systems that eggs are more likely to be inhibited in development to L3s early (2-3 weeks post infection (PI)) and late (beyond 10 weeks PI) after infection and are most resilient to the effect of drugs at about 7 weeks PI. No systematic changes in DrenchRite results were observed over age of worm infection when tested weekly for 2 to 14 week old worms. Large bowel worms of sheep have not generally been examined under LDA conditions so a study was undertaken to determine the LD50s of susceptible Oesophagostomum columbianum (nodule worm) and Chabertia ovina (large mouthed bowel worm) on DrenchRite plates. LD50s for BZ and LEV were approximately 0.04 and 0.8 uM respectively for both worms. For the ML O. columbianum had a much higher LD50 (45 nM) than C. ovina (8 nM). In relation to the other common sheep worms, development characteristics of C. ovina in LDA is like H. contortus while O. columbianum is more like O. circumcincta. Both large bowel worms were very sensitive to BZILEV combinations, with LD50s 4 to 8 fold lower than those observed for H. contortus and O. circumcincta

Design of a diplexing filter for the high resolution IFF antenna of the AN/FPS-3 radar

NRC publication: Ye

Photo-etching for laboratory production of printed circuits

NRC publication: Ye

Radiation patterns of Black Brant II antenna systems

NRC publication: Ye