19 research outputs found

    Factors that influence the prevalence of acaricide resistance and tick-borne diseases.

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    This manuscript provides a summary of the results presented at a symposium organized to accumulate information on factors that influence the prevalence of acaricide resistance and tick-borne diseases. This symposium was part of the 19th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP), held in New Orleans, LA, USA, during August 10-14, 2003. Populations of southern cattle ticks, Boophilus microplus, from Mexico have developed resistance to many classes of acaricide including chlorinated hydrocarbons (DDT), pyrethroids, organophosphates, and formamidines (amitraz). Target site mutations are the most common resistance mechanism observed, but there are examples of metabolic mechanisms. In many pyrethroid resistant strains, a single target site mutation on the Na(+) channel confers very high resistance (resistance ratios: >1000x) to both DDT and all pyrethroid acaricides. Acetylcholine esterase affinity for OPs is changed in resistant tick populations. A second mechanism of OP resistance is linked to cytochrome P450 monooxygenase activity. A PCR-based assay to detect a specific sodium channel gene mutation that is associated with resistance to permethrin has been developed. This assay can be performed on individual ticks at any life stage with results available in a few hours. A number of Mexican strains of B. microplus with varying profiles of pesticide resistance have been genotyped using this test. Additionally, a specific metabolic esterase with permethrin-hydrolyzing activity, CzEst9, has been purified and its gene coding region cloned. This esterase has been associated with high resistance to permethrin in one Mexican tick population. Work is continuing to clone specific acetylcholinesterase (AChE) and carboxylesterase genes that appear to be involved in resistance to organophosphates. Our ultimate goal is the design of a battery of DNA- or ELISA-based assays capable of rapidly genotyping individual ticks to obtain a comprehensive profile of their susceptibility to various pesticides. More outbreaks of clinical bovine babesisois and anaplasmosis have been associated with the presence of synthetic pyrethroid (SP) resistance when compared to OP and amidine resistance. This may be the result of differences in the temporal and geographic patterns of resistance development to the different acaricides. If acaricide resistance develops slowly, herd immunity may not be affected. The use of pesticides for the control of pests of cattle other than ticks can affect the incidence of tick resistance and tick-borne diseases. Simple analytical models of tick- and tsetse-borne diseases suggest that reducing the abundance of ticks, by treating cattle with pyrethroids for example, can have a variety of effects on tick-borne diseases. In the worst-case scenario, the models suggest that treating cattle might not only have no impact on trypanosomosis but could increase the incidence of tick-borne disease. In the best-case, treatment could reduce the incidence of both trypanosomosis and tick-borne diseases Surveys of beef and dairy properties in Queensland for which tick resistance to amitraz was known were intended to provide a clear understanding of the economic and management consequences resistance had on their properties. Farmers continued to use amitraz as the major acaricide for tick control after the diagnosis of resistance, although it was supplemented with moxidectin (dairy farms) or fluazuron, macrocyclic lactones or cypermethrin/chlorfenvinphos

    Learning regional attraction for line segment detection

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    This paper presents regional attraction of line segment maps, and hereby poses the problem of line segment detection (LSD) as a problem of region coloring. Given a line segment map, the proposed regional attraction first establishes the relationship between line segments and regions in the image lattice. Based on this, the line segment map is equivalently transformed to an attraction field map (AFM), which can be remapped to a set of line segments without loss of information. Accordingly, we develop an end-to-end framework to learn attraction field maps for raw input images, followed by a squeeze module to detect line segments. Apart from existing works, the proposed detector properly handles the local ambiguity and does not rely on the accurate identification of edge pixels. Comprehensive experiments on the Wireframe dataset and the YorkUrban dataset demonstrate the superiority of our method. In particular, we achieve an F-measure of 0.831 on the Wireframe dataset, advancing the state-of-the-art performance by 10.3 percent

    Behaviour and Population Dynamics of Entomopathogenic Nematodes Following Application

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    Entomopathogenic nematodes (EPN) of the genera Steinernema and Heterorhabditis are widely used in inundative biological pest control programmes. It has long been recognised that increased understanding of the ecology of EPN is important for better predictions of field performance and environmental risk (Ehlers & Hokkanen, 1996; Gaugler, Lewis, & Stuart, 1997). Increasingly, EPN are also finding a place as model organisms for fundamental studies in behavioural ecology and evolutionary biology (Campos-Herrera, Barbercheck, Hoy, & Stock, 2012). In this chapter, I consider the fate of EPN used in biocontrol, focussing largely on inundative application to soil. The aim is to provide an overview of the transformation of a biotechnological product to an ecological entity, rather than a review of this rather broad topic. There are already several extensive reviews relevant to the subject, including EPN behaviour and their fate in soil (e.g. Griffin, 2012; Kaya, 2002; Lewis, Campbell, Griffin, Kaya, & Peters, 2006; Stuart, Barbercheck, Grewal, Taylor, & Hoy, 2006; see also Chap. 4). It should be noted that, while the concept of this chapter is to follow the fate of commercially produced EPN when applied to soil, many of the laboratory studies cited have used nematodes produced in insects rather than taken from commercial formulations

    Measurement of CP observables in B0 -> D K*0 with D -> K+ K-

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    The decay B0 -> D K*0 and the charge conjugate mode are studied using 1.0fb-1 of pp collision data collected by the LHCb experiment at sqrt(s) = 7TeV in 2011. The CP asymmetry between the B0 -> D K*0 and the B0bar -> D K*0bar decay rates, with the neutral D meson in the CP-even final state K+K-, is found to be A_d_KK = -0.45 +- 0.23 +- 0.02, where the first uncertainty is statistical and the second is systematic. In addition, favoured B0 -> D K*0 decays are reconstructed with the D meson in the non-CP eigenstate K+ pi-. The ratio of the B-flavour averaged decay rates in D decays to CP and non-CP eigenstates is measured to be R_d_KK = 1.36 (+0.37) (-0.32) +- 0.07, where the ratio of the branching fractions of D0 -> K- pi+ to D0 -> K+ K- decays is included as multiplicative factor. The CP asymmetries measured with two control channels, the favoured B0 -> DK*0 decay with D -> K+ pi- and the Bs0bar -> D K*0 decay with D K+ K-, are also reported

    Measurement of the branching fractions of the decays Bs -> D0bar K- π+ and B0 -> D0bar K+ π-

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    The first observation of the decay Bs -> D0bar K- {\pi}+ is reported. The analysis is based on a data sample, corresponding to an integrated luminosity of 1.0 fb-1 of pp collisions, collected with the LHCb detector. The branching fraction relative to that of the topologically similar decay B0 -> D0bar {\pi}+ {\pi}- is measured to be BR(Bs -> D0bar K- {\pi}+)/BR(B0 -> D0bar {\pi}+ {\pi}-) = 1.18 +- 0.05 (stat.) +- 0.12 (syst.). In addition, the relative branching fraction of the decay B0 -> D0bar K+ {\pi}- is measured to be BR(B0 -> D0bar K+ {\pi}-)/BR(B0 -> D0bar {\pi}+ {\pi}-) = 0.106 +- 0.007 (stat.) +- 0.008 (syst.)

    First Observation of the Decays (B)over-bar(0) -> D+K-pi(+)pi(-) and B- -> (DK-)-K-0 pi(+)pi(-)

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    First observations of the Cabibbo-suppressed decays (B) over bar (0) -> D+K-pi(+)pi(-) and B- -> (DK-)-K-0 pi(+)pi(-) are reported using 35 pb(-1) of data collected with the LHCb detector. Their branching fractions are measured with respect to the corresponding Cabibbo-favored decays, from which we obtain B((B) over bar (0) -> D+K-pi(+)pi(-))/B((B) over bar (0) -> D+pi(-)pi(+)pi(-) = (5.9 +/- 1.1 +/- 0.5) x 10(-2) and B(B- -> (DK-)-K-0 pi(+)pi(-))/B(B- -> D-0 pi(-)pi(+)pi(-)) = (0.9 +/- 1.3 +/- 0.9) x 10(-2), where the uncertainties are statistical and systematic, respectively. The B- -> (DK-)-K-0 pi(+)pi(-) decay is particularly interesting, as it can be used in a similar way to B- -> (DK-)-K-0 to measure the Cabibbo-Kobayashi-Maskawa phase gamma

    Measurement of the cross-section for Z->e+e- production in pp collisions at sqrt{s}=7TeV

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    A measurement of the cross-section for pp->Z->e+e- is presented using data at sqrt{s}=7TeV corresponding to an integrated luminosity of 0.94 fb^{-1}. The process is measured within the kinematic acceptance pT>20GeV/c and 2<\eta<4.5 for the daughter electrons and dielectron invariant mass in the range 60--120GeV/c^2. The cross-section is determined to be \sigma(pp->Z->e+e-)=76.0+-0.8+-2.0+-2.6pb where the first uncertainty is statistical, the second is systematic and the third is the uncertainty in the luminosity. The measurement is performed as a function of Z rapidity and as a function of an angular variable which is closely related to the Z transverse momentum. The results are compared with previous LHCb measurements and with theoretical predictions from QCD

    Search for the rare decays B-s(0) -> mu(+)mu(-) and B-0 -> mu(+)mu(-)

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    A search for the decays B-s(0) -> mu(+)mu(-) and B-0 -> mu(+)mu(-) is performed with 0.37 fb(-1) of pp collisions at root s = 7 TeV collected by the LHCb experiment in 2011. The upper limits on the branching fractions are B(B-s(0) -> mu(+)mu(-)) mu(+)mu(-)) mu(+)mu(-)) mu(+)mu(-)) < 3.2 x 10(-9) at 95% confidence level

    First observation of the decays (B)over-bar((s))(0) -> Ds+K-pi(+)pi(-) and (B)over-bar((s))(0) -> Ds(1)(2536)(+)pi(-)

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    The first observation of the decays (B) over bar (0)(s) -> Ds+K-pi(+)pi(-) and (B) over bar (0)(s) -> Ds+K-pi(+)pi(-) are reported using an integrated luminosity of 1.0 fb(-1) recorded by the LHCb experiment. The branching fractions, normalized with respect to (B) over bar (0)(s) -> D-s(+)pi(-)pi(+)pi(-) and (B) over bar (0)(s) -> Ds+K-pi(+)pi(-), respectively, are measured to be B((B) over bar (0)(s)-> DsK-pi(+)pi(-))/B((B) over bar (0)(s)-> D-s pi(-)pi(+)pi(-)) = (5.2 +/- 0.5 +/- 0.3) x 10(-2) and B((B) over bar (0)(s)-> DsK-pi(+)pi(-))/B((B) over bar (0)(s)-> DsK-pi(+)pi(-)) = 0.54 +/- 0.07 +/- 0.07, where the first uncertainty is statistical and the second is systematic. The (B) over bar (0)(s) -> D-s(+) K-pi(+)pi(-) decay is of particular interest as it can be used to measure the weak phase gamma. First observation of the (B) over bar (0)(s) -> D-s1(2536)(+)pi(-), D-s1(+) -> D-s(+) pi(-)pi(+) decay is also presented, and its branching fraction relative to (B) over bar (0)(s) -> D-s(+) pi(-)pi(+)pi(-) is found to be B((B) over bar (0)(s) -> D-s1(2536)(+)pi(-),D-s1(+)-> D-s(+)pi(-)pi(+)/B((B) over bar (0)(s) -> D-s(+)pi(-)pi(+)pi(-))) = (4.0 +/- 1.0 +/- 0.4) x 10(-3). DOI: 10.1103/PhysRevD.86.112005 RI Coca, Cornelia/B-6015-2012; Galli, Domenico/A-1606-2012; Sarti, Alessio/I-2833-201
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