7,908 research outputs found
New Host Records of Parasitic Hymenoptera in Clearwing Moths (Lepidoptera: Sesiidae)
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
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
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
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
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 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
HO 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
© 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
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
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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