Simultaneous disruption of pheromone communication and mating in Cydia pomonella, Choristoneura rosaceana and Pandemis limitata Lepidoptera:Tortricidae) using Isomate-CM/LR in apple orchards

Simultaneous disruption of pheromone communication and mating of codling moth, Cydia pomonella (L), and four leafroller (Lepidoptera:Tortricidae) species, Choristoneura rosaceana (Harris), Pandemis limitata (Robinson), Archips rosanus (L.) and Archips argyrospilus (Walker ) using an incomplete mixture of their individual pheromone components was studied in organic apple orchards, in Cawston, BC, 1997. Multi-species disruption with a single 500 'rope' dispenser / ha application of Isomate-CM/LR was compared to a single 500 dispenser / ha application of Isomate-C. Season-long disruption was assessed using synthetic pheromone traps and laboratory-reared females in mating tables. Mean seasonal recaptures of sterile male C. pomonella, using 10 mg codlemone lures in orchards receiving releases of 1000 males / ha / week, were not significantly different in half-orchard plots (0.5 - 1 ha) of Isomate-CM/LR or Isomate-C. Mating of C. pomonella in Isomate-C- and Isomate-CM/LR-treated plots was negligible. Isomate-CM/LR significantly reduced catches of C. rosaceana and P. limitata relative to catches in Isomate-C-treated plots. Few A. rosanus and no A. argyrospilus were caught in any orchard. Mating of C. rosaceana and P. limitata in Isomate-CM/LR treated plots was significantly less than in Isomate-C-treated plots. Our results indicate Isomate-CM/LR will disrupt mating of C. pomonella equivalent to Isomate-C and may provide sufficient disruption of leafrollers to supplement biological control in organic orchards. Further studies are needed to show impacts of mating disruption on leafroller populations and damage when applied to larger areas and for several seasons sequentially

The time-reversal test for stochastic quantum dynamics

The calculation of quantum dynamics is currently a central issue in theoretical physics, with diverse applications ranging from ultra-cold atomic Bose-Einstein condensates (BEC) to condensed matter, biology, and even astrophysics. Here we demonstrate a conceptually simple method of determining the regime of validity of stochastic simulations of unitary quantum dynamics by employing a time-reversal test. We apply this test to a simulation of the evolution of a quantum anharmonic oscillator with up to $6.022\times10^{23}$ (Avogadro's number) of particles. This system is realisable as a Bose-Einstein condensate in an optical lattice, for which the time-reversal procedure could be implemented experimentally.Comment: revtex4, two figures, four page

Antennal detection of sex pheromone by female Pandemis limitata (Robinson) (Lepidoptera: Tortricidae) and its impact on their calling behaviour

Previous observations lead us to believe that female Pandemis limitata (Robinson) (0 to 24 h old) are as attractive as their pheromone gland extract to males in clean air, but are more attractive in an environment permeated with their major pheromone component(Z)-11-tetradecenyl acetate. Therefore, in this study, we tested the hypothesis that females can detect and/or respond to their pheromone components. Using electroantennographic detection, we found female P. limitata able to perceive both of their known pheromone components, (Z)-11-tetradecenyl acetate and (Z)-9-tetradecenyl acetate. Female antennal response was found to be 46.3% weaker than that of males, under identical conditions, with male antennae producing significantly higher deflections to the higher pheromone doses tested and to the plant volatile,(E)-2-hexanal. Observations of females in clean air versus (Z)-11-tetradecenyl acetate-permeated air showed no significant differences with respect to onset time, frequency or duration of calling. Females moved significantly less often in a (Z)-11-tetradecenyl acetate-permeated portion of a flight tunnel than in the corresponding clean-air portion

Loss-Induced Limits to Phase Measurement Precision with Maximally Entangled States

The presence of loss limits the precision of an approach to phase measurement using maximally entangled states, also referred to as NOON states. A calculation using a simple beam-splitter model of loss shows that, for all nonzero values L of the loss, phase measurement precision degrades with increasing number N of entangled photons for N sufficiently large. For L above a critical value of approximately 0.785, phase measurement precision degrades with increasing N for all values of N. For L near zero, phase measurement precision improves with increasing N down to a limiting precision of approximately 1.018 L radians, attained at N approximately equal to 2.218/L, and degrades as N increases beyond this value. Phase measurement precision with multiple measurements and a fixed total number of photons N_T is also examined. For L above a critical value of approximately 0.586, the ratio of phase measurement precision attainable with NOON states to that attainable by conventional methods using unentangled coherent states degrades with increasing N, the number of entangled photons employed in a single measurement, for all values of N. For L near zero this ratio is optimized by using approximately N=1.279/L entangled photons in each measurement, yielding a precision of approximately 1.340 sqrt(L/N_T) radians.Comment: Additional references include

Continuous macroscopic limit of a discrete stochastic model for interaction of living cells

In the development of multiscale biological models it is crucial to establish a connection between discrete microscopic or mesoscopic stochastic models and macroscopic continuous descriptions based on cellular density. In this paper a continuous limit of a two-dimensional Cellular Potts Model (CPM) with excluded volume is derived, describing cells moving in a medium and reacting to each other through both direct contact and long range chemotaxis. The continuous macroscopic model is obtained as a Fokker-Planck equation describing evolution of the cell probability density function. All coefficients of the general macroscopic model are derived from parameters of the CPM and a very good agreement is demonstrated between CPM Monte Carlo simulations and numerical solution of the macroscopic model. It is also shown that in the absence of contact cell-cell interactions, the obtained model reduces to the classical macroscopic Keller-Segel model. General multiscale approach is demonstrated by simulating spongy bone formation from loosely packed mesenchyme via the intramembranous route suggesting that self-organizing physical mechanisms can account for this developmental process.Comment: 4 pages, 3 figure

Monte Carlo techniques for real-time quantum dynamics

The stochastic-gauge representation is a method of mapping the equation of motion for the quantum mechanical density operator onto a set of equivalent stochastic differential equations. One of the stochastic variables is termed the "weight", and its magnitude is related to the importance of the stochastic trajectory. We investigate the use of Monte Carlo algorithms to improve the sampling of the weighted trajectories and thus reduce sampling error in a simulation of quantum dynamics. The method can be applied to calculations in real time, as well as imaginary time for which Monte Carlo algorithms are more-commonly used. The method is applicable when the weight is guaranteed to be real, and we demonstrate how to ensure this is the case. Examples are given for the anharmonic oscillator, where large improvements over stochastic sampling are observed.Comment: 28 pages, submitted to J. Comp. Phy