Powdery bark in Eucalyptus accedens deters arthropods? An evaluation using ants

Powderbark wandoo (Eucalyptus accedens) has a powdery triterpenoid-containing substance on the surface of its smooth bark, which is formed from sloughing peridermal cells. When compared with the similar-appearing wandoo (E. wandoo), which occurs inthe same area and which does not accumulate powder, fewer bark-associated arthropods are found. Exposure to this powder accelerated mortality of the ant, Iridomyrmexchasei, a species that tends scale and other sap-sucking insects on the foliage of eucalypts. Ants of this and two other species were unable to reach baits on the top of vertical wooden dowels that had been coated with powder taken from the bark of E. accedens. The powdermay deter arthropods from living or moving on the bark by chemical or physical means. It is postulated that the function of the powder is to reduce the threat from herbivorous or scale-tending arthropods that may live on, or traverse, the bark of this species

Geophysical Methods: an Overview

Geophysics is expected to have a major role in lunar resource assessment when manned systems return to the Moon. Geophysical measurements made from a lunar rover will contribute to a number of key studies: estimating regolith thickness, detection of possible large-diameter lava tubes within maria basalts, detection of possible subsurface ice in polar regions, detection of conductive minerals that formed directly from a melt (orthomagmatic sulfides of Cu, Ni, Co), and mapping lunar geology beneath the regolith. The techniques that can be used are dictated both by objectives and by our abilities to adapt current technology to lunar conditions. Instrument size, weight, power requirements, and freedom from orientation errors are factors we have considered. Among the geophysical methods we believe to be appropriate for a lunar resource assessment are magnetics, including gradiometry, time-domain magnetic induction, ground-penetrating radar, seismic reflection, and gravimetry

Trunk invertebrate faunas of Western Australian forests and woodlands: Influence of tree species and season

Trunk-associated invertebrates were sampled on two rough-barked tree species (jarrah, Eucalyptus marginata and marri, E. calophylla) at Karragullen, in the hills near Perth, Western Australia, and on these two species plus two smooth-barked species (wandoo, E. wandoo, and powderbark wandoo, E. accedens) at Dryandra, a drier site situated 150 km to the south-east. Invertebrates were sampled by intercept traps, which collect animals that attempt to land on the trunks, and photo-eclector bark traps, which collect invertebrates that move, or live, on the trunk. The range and abundance of invertebrates sampled was generally greater in the intercept than the bark traps. Invertebrate abundance and activity (but not biomass) on bark was strongly seasonal, with greater numbers being found during the moister periods. The two smooth-barked species supported, and were visited by, more invertebrates than the two rough-barked species. There was some evidence that jarrah supported more invertebrates than marri at both Karragullen and Dryandra, although the results were equivocal. Within the two smooth-barked species, wandoo tended to support more invertebrates than powderbark wandoo. These trends are discussed in terms of the characteristics of the bark of these trees and the environments in which they occur

Strong magnetic coupling of an ultracold gas to a superconducting waveguide cavity

Placing an ensemble of $10^6$ ultracold atoms in the near field of a superconducting coplanar waveguide resonator (CPWR) with $Q \sim 10^6$ one can achieve strong coupling between a single microwave photon in the CPWR and a collective hyperfine qubit state in the ensemble with $g_\textit{eff} / {2 \pi} \sim 40$ kHz larger than the cavity line width of ${\kappa}/{2 \pi} \sim 7$ kHz. Integrated on an atomchip such a system constitutes a hybrid quantum device, which also can be used to interconnect solid-state and atomic qubits, to study and control atomic motion via the microwave field, observe microwave super-radiance, build an integrated micro maser or even cool the resonator field via the atoms

Approaching Unit Visibility for Control of a Superconducting Qubit with Dispersive Readout

In a Rabi oscillation experiment with a superconducting qubit we show that a visibility in the qubit excited state population of more than 90 % can be attained. We perform a dispersive measurement of the qubit state by coupling the qubit non-resonantly to a transmission line resonator and probing the resonator transmission spectrum. The measurement process is well characterized and quantitatively understood. The qubit coherence time is determined to be larger than 500 ns in a measurement of Ramsey fringes.Comment: 4 pages, 5 figures, version with high resolution figures available at http://www.eng.yale.edu/rslab/Andreas/content/science/PubsPapers.htm

Risk patterns and correlated brain activities. Multidimensional statistical analysis of FMRI data in economic decision making study

Decision making usually involves uncertainty and risk. Understanding which parts of the human brain are activated during decisions under risk and which neural processes underly (risky) investment decisions are important goals in neuroeconomics. Here, we analyze functional magnetic resonance imaging (fMRI) data on 17 subjects who were exposed to an investment decision task from Mohr, Biele, Krugel, Li, and Heekeren (in NeuroImage 49, 2556–2563, 2010b). We obtain a time series of three-dimensional images of the blood-oxygen-level dependent (BOLD) fMRI signals. We apply a panel version of the dynamic semiparametric factor model (DSFM) presented in Park, Mammen, Wolfgang, and Borak (in Journal of the American Statistical Association 104(485), 284–298, 2009) and identify task-related activations in space and dynamics in time. With the panel DSFM (PDSFM) we can capture the dynamic behavior of the specific brain regions common for all subjects and represent the high-dimensional time-series data in easily interpretable low-dimensional dynamic factors without large loss of variability. Further, we classify the risk attitudes of all subjects based on the estimated low-dimensional time series. Our classification analysis successfully confirms the estimated risk attitudes derived directly from subjects’ decision behavior

Qubit-photon interactions in a cavity: Measurement induced dephasing and number splitting

We theoretically study measurement induced-dephasing of a superconducting qubit in the circuit QED architecture and compare the results to those obtained experimentally by Schuster {\it et al.}, [Phys. Rev. Lett. 94, 123602 (2005)]. Strong coupling of the qubit to the resonator leads to a significant ac-Stark shift of the qubit transition frequency. As a result, quantum fluctuations in the photon number populating the resonator cause dephasing of the qubit. We find good agreement between the predicted line shape of the qubit spectrum and the experimental results. Furthermore, in the strong dispersive limit, where the Stark shift per photon is large compared to the cavity decay rate and the qubit linewidth, we predict that the qubit spectrum will be split into multiple peaks, with each peak corresponding to a different number of photons in the cavity.Comment: 15 pages and 10 figures. Section IV revised. Author and references added. Version with high resolution figures available at available at http://www.physique.usherbrooke.ca/~ablais/publications.ht

Abrupt Transition between Thermally-Activated Relaxation and Quantum Tunneling in a Molecular Magnet

We report Hall sensor measurements of the magnetic relaxation of Mn$_{12}$ acetate as a function of magnetic field applied along the easy axis of magnetization. Data taken at a series of closely-spaced temperatures between 0.24 K and 1.4 K provide strong new evidence for an abrupt ``first-order'' transition between thermally-assisted relaxation and magnetic decay via quantum tunneling.Comment: 4 pages, including 7 figure