7,139 research outputs found

    New Host Records of Parasitic Hymenoptera in Clearwing Moths (Lepidoptera: Sesiidae)

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    Synanthedon pictipes is host for Dibrachus cavus; Podosesia aureocincta hosts Phaeogenes ater, Macrocentrus marginator, and Lissonota sp.; Podosesia syringae hosts Lissonota sp

    Emergence and Adult Biology of \u3ci\u3eAgrilus Difficilis\u3c/i\u3e (Coleoptera: Buprestidae), a Pest of Honeylocust, \u3ci\u3eGleditsia Triacanthos\u3c/i\u3e

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    Emergence and adult biology of Agrilus difficilis were examined in relation to its host Gleditsia triacanthos. began as early as 5 June in 1982 and completed as late as 22 July in 1983. Females lived significantly longer, 48 days, than males, 29 days. Average fecundity was one egg per day during a 36-day oviposition period

    Discrete-valued Levy processes and low latency financial econometrics

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    Motivated by features of low latency data in finance we study in detail discrete-valued Levy processes as the basis of price processes for high frequency econometrics. An important case of this is a Skellam process, which is the difference of two independent Poisson processes. We propose a natural generalisation which is the difference of two negative binomial processes. We apply these models in practice to low latency data for a variety of different types of futures contracts.futures markets; high frequency econometrics; low latency data; negative binomial; Skellam distribution.

    New Reports of Exotic and Native Ambrosia and Bark Beetle Species (Coleoptera: Curculionidae: Scolytinae) From Ohio

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    In a 2007 survey of ambrosia and bark beetles (Coleoptera: Curculionidae: Scolytinae) along a transect in northeastern Ohio, we collected six exotic and three native species not previously reported from the state. These species include the exotic ambrosia beetles Ambrosiodmus rubricollis (Eichhoff), Dryoxylon onoharaensum (Murayama), Euwallacea validus (Eichhoff), Xyleborus californicus Wood, Xyleborus pelliculosusEichhoff, and Xylosandrus crassiusculus (Motschulsky). The native ambrosia beetle Corthylus columbianus Hopkins, and the native bark beetles Dryocoetes autographus (Ratzeburg) and Hylastes tenuis Eichhoff are also reported from Ohio for the first time. Our study suggests a northward range expansion for five of the six exotic species including, X. crassiusculus, which is an important pest of nursery and orchard crops in the southeastern United States

    Monovalent counterion distributions at highly charged water interfaces: Proton-transfer and Poisson-Boltzmann theory

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    Surface sensitive synchrotron-X-ray scattering studies reveal the distributions of monovalent ions next to highly charged interfaces. A lipid phosphate (dihexadecyl hydrogen-phosphate) was spread as a monolayer at the air-water interface, containing CsI at various concentrations. Using anomalous reflectivity off and at the L3L_3 Cs+^+ resonance, we provide, for the first time, spatial counterion distributions (Cs+^+) next to the negatively charged interface over a wide range of ionic concentrations. We argue that at low salt concentrations and for pure water the enhanced concentration of hydroniums H3_3O+^+ at the interface leads to proton-transfer back to the phosphate group by a high contact-potential, whereas high salt concentrations lower the contact-potential resulting in proton-release and increased surface charge-density. The experimental ionic distributions are in excellent agreement with a renormalized-surface-charge Poisson-Boltzmann theory without fitting parameters or additional assumptions

    Isotopic evidence for the formation of the moon in a canonical giant impact

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nielsen, S. G., Bekaert, D. V., & Auro, M. Isotopic evidence for the formation of the moon in a canonical giant impact. Nature Communications, 12(1), (2021): 1817, https://doi.org/10.1038/s41467-021-22155-7.Isotopic measurements of lunar and terrestrial rocks have revealed that, unlike any other body in the solar system, the Moon is indistinguishable from the Earth for nearly every isotopic system. This observation, however, contradicts predictions by the standard model for the origin of the Moon, the canonical giant impact. Here we show that the vanadium isotopic composition of the Moon is offset from that of the bulk silicate Earth by 0.18 ± 0.04 parts per thousand towards the chondritic value. This offset most likely results from isotope fractionation on proto-Earth during the main stage of terrestrial core formation (pre-giant impact), followed by a canonical giant impact where ~80% of the Moon originates from the impactor of chondritic composition. Our data refute the possibility of post-giant impact equilibration between the Earth and Moon, and implies that the impactor and proto-Earth mainly accreted from a common isotopic reservoir in the inner solar system.This study was funded by NASA Emerging Worlds grant NNX16AD36G to S.G.N. We thank NASA-JSC, Tony Irving, and Thorsten Kleine for access to meteorite and Apollo mission samples. US Antarctic meteorite samples are recovered by the Antarctic Search for Meteorites (ANSMET) program, which has been funded by NSF and NASA, and characterized and curated by the Astromaterials Curation Office at NASA Johnson Space Center and the Department of Mineral Sciences of the Smithsonian Institution. J. Blusztajn is thanked for help with mass spectrometry support at WHOI

    Monitoring Entanglement Evolution and Collective Quantum Dynamics

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    We generalize a recently developed scheme for monitoring coherent quantum dynamics with good time-resolution and low backaction [Reuther et al., Phys. Rev. Lett. 102, 033602 (2009)] to the case of more complex quantum dynamics of one or several qubits. The underlying idea is to measure with lock-in techniques the response of the quantum system to a high-frequency ac field. We demonstrate that this scheme also allows one to observe quantum dynamics with many frequency scales, such as that of a qubit undergoing Landau-Zener transitions. Moreover, we propose how to measure the entanglement between two qubits as well as the collective dynamics of qubit arrays.Comment: 11 pages, 5 figure

    Dynamics of a quantum reference frame undergoing selective measurements and coherent interactions

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    We consider the dynamics of a quantum directional reference frame undergoing repeated interactions. We first describe how a precise sequence of measurement outcomes affects the reference frame, looking at both the case that the measurement record is averaged over and the case wherein it is retained. We find, in particular, that there is interesting dynamics in the latter situation which cannot be revealed by considering the averaged case. We then consider in detail how a sequence of rotationally invariant unitary interactions affects the reference frame, a situation which leads to quite different dynamics than the case of repeated measurements. We then consider strategies for correcting reference frame drift if we are given a set of particles with polarization opposite to the direction of drift. In particular, we find that by implementing a suitably chosen unitary interaction after every two measurements we can eliminate the rotational drift of the reference frame.Comment: 9 pages, 5 figure
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