44 research outputs found

    Towards an early warning system for Rhodesian sleeping sickness in savannah areas: man-like traps for tsetse flies

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    Background: In the savannahs of East and Southern Africa, tsetse flies (Glossina spp.) transmit Trypanosoma brucei rhodesiense which causes Rhodesian sleeping sickness, the zoonotic form of human African trypanosomiasis. The flies feed mainly on wild and domestic animals and are usually repelled by humans. However, this innate aversion to humans can be undermined by environmental stresses on tsetse populations, so increasing disease risk. To monitor changes in risk, we need traps designed specifically to quantify the responsiveness of savannah tsetse to humans, but the traps currently available are designed to simulate other hosts. Methodology/Principal Findings: In Zimbabwe, two approaches were made towards developing a man-like trap for savannah tsetse: either modifying an ox-like trap or creating new designs. Tsetse catches from a standard ox-like trap used with and without artificial ox odor were reduced by two men standing nearby, by an average of 34% for Glossina morsitans morsitans and 56% for G. pallidipes, thus giving catches more like those made by hand-nets from men. Sampling by electrocuting devices suggested that the men stopped flies arriving near the trap and discouraged trap-entering responses. Most of human repellence was olfactory, as evidenced by the reduction in catches when the trap was used with the odor of hidden men. Geranyl acetone, known to occur in human odor, and dispensed at 0.2 mg/h, was about as repellent as human odor but not as powerfully repellent as wood smoke. New traps looking and smelling like men gave catches like those from men. Conclusion/Significance: Catches from the completely new man-like traps seem too small to give reliable indices of human repellence. Better indications would be provided by comparing the catches of an ox-like trap either with or without artificial human odor. The chemistry and practical applications of the repellence of human odor and smoke deserve further study

    Quantum numbers of the X(3872)X(3872) state and orbital angular momentum in its ρ0Jψ\rho^0 J\psi decay

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    Angular correlations in B+→X(3872)K+B^+\to X(3872) K^+ decays, with X(3872)→ρ0J/ψX(3872)\to \rho^0 J/\psi, ρ0→π+π−\rho^0\to\pi^+\pi^- and J/ψ→Ό+Ό−J/\psi \to\mu^+\mu^-, are used to measure orbital angular momentum contributions and to determine the JPCJ^{PC} value of the X(3872)X(3872) meson. The data correspond to an integrated luminosity of 3.0 fb−1^{-1} of proton-proton collisions collected with the LHCb detector. This determination, for the first time performed without assuming a value for the orbital angular momentum, confirms the quantum numbers to be JPC=1++J^{PC}=1^{++}. The X(3872)X(3872) is found to decay predominantly through S wave and an upper limit of 4%4\% at 95%95\% C.L. is set on the fraction of D wave.Comment: 16 pages, 4 figure

    A Novel Synthetic Odorant Blend for Trapping of Malaria and Other African Mosquito Species

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    Estimating the biting fraction of mosquitoes is of critical importance for risk assessment of malaria transmission. Here, we present a novel odor-based tool that has been rigorously assessed in semi-field assays and traditional African villages for estimating the number of mosquitoes that enter houses in search of a blood meal. A standard synthetic blend (SB) consisting of ammonia, (S)-lactic acid, tetradecanoic acid, and carbon dioxide was complemented with isovaleric acid, 4,5 dimethylthiazole, 2-methyl-1-butanol, and 3-methyl-1-butanol in various combinations and concentrations, and tested for attractiveness to the malaria mosquito Anopheles gambiae. Compounds were released through low density polyethylene (LDPE) material or from nylon strips (nylon). Studies were done in a semi-field facility and two traditional villages in western Kenya. The alcohol 3-methyl-1-butanol significantly increased the attraction of SB. The other compounds proved less effective or inhibitory. Tested in a village, 3-methyl-1-butanol, released from LDPE, increased the attraction of SB. Further studies showed a significantly enhanced attraction of adding 3-methyl-1-butanol to SB compared to previously-published attractive blends both under semi-field and village conditions. Other mosquito species with relevance for public health were collected with this blend in significantly higher numbers as well. These results demonstrate the advent of a novel, reliable odor-based sampling tool for the collection of malaria and other mosquitoes. The advantage of this odor-based tool over existing mosquito sampling tools is its reproducibility, objectiveness, and relatively low cost compared to current standards of CDC light traps or the human landing catch

    Observation of Z production in proton-lead collisions at LHCb

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    The first observation of Z boson production in proton-lead collisions at a centre-of-mass energy per proton-nucleon pair of root(s) N N = 5TeV is presented. The data sample corresponds to an integrated luminosity of 1.6 nb(-1) collected with the LHCb detector. The Z candidates are reconstructed from pairs of oppositely charged muons with pseudorapidities between 2.0 and 4.5 and transverse momenta above 20 GeV/c. The invariant dimuon mass is restricted to the range 60-120 GeV/c. The Z production cross-section is measured to be sigma(Z ->mu+mu-) (fwd) = 13.5(-4.0)(+5.4)(stat.) +/- 1.2(syst.) nb in the direction of the proton beam and sigma(Z ->mu+mu-) (bwd) = 10.7(-5.1)(+8.4)(stat.) +/- 1.0(syst.) nb in the direction of the lead beam, where the first uncertainty is statistical and the second systematic

    Measurement of the Bs0→J/ψK∗0B^0_s\rightarrow J/\psi K^{*0} branching fraction and angular amplitudes

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    A search for the decay Bs0→J/ψK∗0B^0_s\rightarrow J/\psi K^{*0} with K∗0→K−π+K^{*0} \rightarrow K^-\pi^+ is performed with 0.37 fb−1^{-1} of pppp collisions at s\sqrt{s} = 7 TeV collected by the LHCb experiment, finding a \Bs \to J\psi K^-\pi^+ peak of 114±11114 \pm 11 signal events. The K−π+K^-\pi^+ mass spectrum of the candidates in the Bs0B^0_s peak is dominated by the K∗0K^{*0} contribution. Subtracting the non-resonant K−π+K^-\pi^+ component, the branching fraction of \BsJpsiKst is (4.4−0.4+0.5±0.8)×10−5(4.4_{-0.4}^{+0.5} \pm 0.8) \times 10^{-5}, where the first uncertainty is statistical and the second systematic. A fit to the angular distribution of the decay products yields the \Kst polarization fractions fL=0.50±0.08±0.02f_L = 0.50 \pm 0.08 \pm 0.02 and f∣∣=0.19−0.08+0.10±0.02f_{||} = 0.19^{+0.10}_{-0.08} \pm 0.02

    Remote Acoustic Emission Spectrography (RAES)

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    Measurements of long-range near-side angular correlations in √sN N = 5 TeV proton-lead collisions in the forward region

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    Two-particle angular correlations are studied in proton-lead collisions at a nucleon–nucleon centre-of-mass energy of sNN=5 TeV, collected with the LHCb detector at the LHC. The analysis is based on data recorded in two beam configurations, in which either the direction of the proton or that of the lead ion is analysed. The correlations are measured in the laboratory system as a function of relative pseudorapidity, Δη, and relative azimuthal angle, Δϕ, for events in different classes of event activity and for different bins of particle transverse momentum. In high-activity events a long-range correlation on the near side, Δϕ≈0, is observed in the pseudorapidity range 2.0<η<4.9. This measurement of long-range correlations on the near side in proton-lead collisions extends previous observations into the forward region up to η=4.9. The correlation increases with growing event activity and is found to be more pronounced in the direction of the lead beam. However, the correlation in the direction of the lead and proton beams are found to be compatible when comparing events with similar absolute activity in the direction analysed

    Measurements of long-range near-side angular correlations in √sN N = 5 TeV proton-lead collisions in the forward region

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    Two-particle angular correlations are studied in proton-lead collisions at a nucleon–nucleon centre-of-mass energy of sNN=5 TeV, collected with the LHCb detector at the LHC. The analysis is based on data recorded in two beam configurations, in which either the direction of the proton or that of the lead ion is analysed. The correlations are measured in the laboratory system as a function of relative pseudorapidity, Δη, and relative azimuthal angle, Δϕ, for events in different classes of event activity and for different bins of particle transverse momentum. In high-activity events a long-range correlation on the near side, Δϕ≈0, is observed in the pseudorapidity range 2.0<η<4.9. This measurement of long-range correlations on the near side in proton-lead collisions extends previous observations into the forward region up to η=4.9. The correlation increases with growing event activity and is found to be more pronounced in the direction of the lead beam. However, the correlation in the direction of the lead and proton beams are found to be compatible when comparing events with similar absolute activity in the direction analysed
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