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

Acoustic Events in the Solar Atmosphere from Hinode/SOT NFI observations

We investigate the properties of acoustic events (AEs), defined as spatially concentrated and short duration energy flux, in the quiet sun using observations of a 2D field of view (FOV) with high spatial and temporal resolution provided by the Solar Optical Telescope (SOT) onboard \textit{Hinode}. Line profiles of Fe \textsc{i} 557.6 nm were recorded by the Narrow band Filter Imager (NFI) on a $82" \times 82"$ FOV during 75 min with a time step of 28.75 s and 0.08$"$ pixel size. Vertical velocities were computed at three atmospheric levels (80, 130 and 180 km) using the bisector technique allowing the determination of energy flux in the range 3-10 mHz using two complementary methods (Hilbert transform and Fourier power spectra). Horizontal velocities were computed using local correlation tracking (LCT) of continuum intensities providing divergences. The net energy flux is upward. In the range 3-10 mHz, a full FOV space and time averaged flux of 2700 W m$^{-2}$ (lower layer 80-130 km) and 2000 W m$^{-2}$ (upper layer 130-180 km) is concentrated in less than 1% of the solar surface in the form of narrow (0.3$"$) AE. Their total duration (including rise and decay) is of the order of $10^{3}$ s. Inside each AE, the mean flux is $1.6 10^{5}$ W m$^{-2}$ (lower layer) and $1.2 10^{5}$ W m$^{-2}$ (upper). Each event carries an average energy (flux integrated over space and time) of $2.5 10^{19}$ J (lower layer) to $1.9 10^{19}$ J (upper). More than $10^{6}$ events could exist permanently on the Sun, with a birth and decay rate of 3500 s$^{-1}$. Most events occur in intergranular lanes, downward velocity regions, and areas of converging motions.Comment: 18 pages, 10 figure

On Nonlinear Functionals of Random Spherical Eigenfunctions

We prove Central Limit Theorems and Stein-like bounds for the asymptotic behaviour of nonlinear functionals of spherical Gaussian eigenfunctions. Our investigation combine asymptotic analysis of higher order moments for Legendre polynomials and, in addition, recent results on Malliavin calculus and Total Variation bounds for Gaussian subordinated fields. We discuss application to geometric functionals like the Defect and invariant statistics, e.g. polyspectra of isotropic spherical random fields. Both of these have relevance for applications, especially in an astrophysical environment.Comment: 24 page

Can sexual selection drive female life histories? A comparative study on Galliform birds

Sexual selection is an important driver of many of the most spectacular morphological traits that we find in the animal kingdom (for example see Andersson, 1994). As such, sexual selection is most often emphasized as

Elliptic curves of large rank and small conductor

For r=6,7,...,11 we find an elliptic curve E/Q of rank at least r and the smallest conductor known, improving on the previous records by factors ranging from 1.0136 (for r=6) to over 100 (for r=10 and r=11). We describe our search methods, and tabulate, for each r=5,6,...,11, the five curves of lowest conductor, and (except for r=11) also the five of lowest absolute discriminant, that we found.Comment: 16 pages, including tables and one .eps figure; to appear in the Proceedings of ANTS-6 (June 2004, Burlington, VT). Revised somewhat after comments by J.Silverman on the previous draft, and again to get the correct page break

Genetic clustering on the hippocampal surface for genome-wide association studies

Imaging genetics aims to discover how variants in the human genome influence brain measures derived from images. Genome-wide association scans (GWAS) can screen the genome for common differences in our DNA that relate to brain measures. In small samples, GWAS has low power as individual gene effects are weak and one must also correct for multiple comparisons across the genome and the image. Here we extend recent work on genetic clustering of images, to analyze surface-based models of anatomy using GWAS. We performed spherical harmonic analysis of hippocampal surfaces, automatically extracted from brain MRI scans of 1254 subjects. We clustered hippocampal surface regions with common genetic influences by examining genetic correlations (rg) between the normalized deformation values at all pairs of surface points. Using genetic correlations to cluster surface measures, we were able to boost effect sizes for genetic associations, compared to clustering with traditional phenotypic correlations using Pearson's r

The Crossing Statistic: Dealing with Unknown Errors in the Dispersion of Type Ia Supernovae

We propose a new statistic that has been designed to be used in situations where the intrinsic dispersion of a data set is not well known: The Crossing Statistic. This statistic is in general less sensitive than `chi^2' to the intrinsic dispersion of the data, and hence allows us to make progress in distinguishing between different models using goodness of fit to the data even when the errors involved are poorly understood. The proposed statistic makes use of the shape and trends of a model's predictions in a quantifiable manner. It is applicable to a variety of circumstances, although we consider it to be especially well suited to the task of distinguishing between different cosmological models using type Ia supernovae. We show that this statistic can easily distinguish between different models in cases where the `chi^2' statistic fails. We also show that the last mode of the Crossing Statistic is identical to `chi^2', so that it can be considered as a generalization of `chi^2'.Comment: 14 pages, 5 figures. Paper restructured and extended and new interpretation of the method presented. New results concerning model selection. Treatment and error-analysis made fully model independent. References added. Accepted for publication in JCA

Higher Twist Distribution Amplitudes of the Nucleon in QCD

We present the first systematic study of higher-twist light-cone distribution amplitudes of the nucleon in QCD. We find that the valence three-quark state is described at small transverse separations by eight independent distribution amplitudes. One of them is leading twist-3, three distributions are twist-4 and twist-5, respectively, and one is twist-6. A complete set of distribution amplitudes is constructed, which satisfies equations of motion and constraints that follow from conformal expansion. Nonperturbative input parameters are estimated from QCD sum rules.Comment: 29 pages, 4 figures, eqn in (3.19) corrected, table 3 accordingly changed, some typos fixe

Multiscale magnetic underdense regions on the solar surface: Granular and Mesogranular scales

The Sun is a non-equilibrium dissipative system subjected to an energy flow which originates in its core. Convective overshooting motions create temperature and velocity structures which show a temporal and spatial evolution. As a result, photospheric structures are generally considered to be the direct manifestation of convective plasma motions. The plasma flows on the photosphere govern the motion of single magnetic elements. These elements are arranged in typical patterns which are observed as a variety of multiscale magnetic patterns. High resolution magnetograms of quiet solar surface revealed the presence of magnetic underdense regions in the solar photosphere, commonly called voids, which may be considered a signature of the underlying convective structure. The analysis of such patterns paves the way for the investigation of all turbulent convective scales from granular to global. In order to address the question of magnetic structures driven by turbulent convection at granular and mesogranular scales we used a "voids" detection method. The computed voids distribution shows an exponential behavior at scales between 2 and 10 Mm and the absence of features at 5-10 Mm mesogranular scales. The absence of preferred scales of organization in the 2-10 Mm range supports the multiscale nature of flows on the solar surface and the absence of a mesogranular convective scale

Active region formation through the negative effective magnetic pressure instability

The negative effective magnetic pressure instability operates on scales encompassing many turbulent eddies and is here discussed in connection with the formation of active regions near the surface layers of the Sun. This instability is related to the negative contribution of turbulence to the mean magnetic pressure that causes the formation of large-scale magnetic structures. For an isothermal layer, direct numerical simulations and mean-field simulations of this phenomenon are shown to agree in many details in that their onset occurs at the same depth. This depth increases with increasing field strength, such that the maximum growth rate of this instability is independent of the field strength, provided the magnetic structures are fully contained within the domain. A linear stability analysis is shown to support this finding. The instability also leads to a redistribution of turbulent intensity and gas pressure that could provide direct observational signatures.Comment: 19 pages, 10 figures, submitted to Solar Physic