Ecology of anthocorid (Hemipt.: Anthocoridae) predators of the pear psylla (Homopt.: Psyllidae) in the Okanagan Valley, British Columbia

The supposition is not valid that the disappearance of the native <i>Anthocoris melanocerus</i> from pear orchards late in the summer is because of competitive displacement by the introduced <i>A. nemoralis</i>. It is because <i>A. melanocerus</i> migrates to where prey are most abundant whereas <i>A. nemoralis</i> remains on pear. <i>A. melanocerus</i> is concentrated on willows in the spring, moves to pear when <i>Psylla pyricola</i> becomes abundant, and moves to cottonwood when aphids on it become abundant and the numbers of <i>P. pyricola</i> on pear have become low

Influence of the charge carrier tunneling processes on the recombination dynamics in single lateral quantum dot molecules

We report on the charge carrier dynamics in single lateral quantum dot molecules and the effect of an applied electric field on the molecular states. Controllable electron tunneling manifests itself in a deviation from the typical excitonic decay behavior which is strongly influenced by the tuning electric field and inter-molecular Coulomb energies. A rate equation model is developed to gain more insight into the charge transfer and tunneling mechanisms. Non-resonant (phonon-mediated) electron tunneling which changes the molecular exciton character from direct to indirect, and vice versa, is found to be the dominant tunable decay mechanism of excitons besides radiative recombination.Comment: 4 pages, 4 figure

Probing the switching mechanism in ZnO nanoparticle memristors

We investigate the resistance switching mechanism in memristors based on colloidal ZnO nanoparticles using electroabsorption (EA) spectroscopy. In this EA experiment, we incorporate a small amount of low-bandgap polymer, poly(9,9-dioctylfluorene-cobenzothiadiazole) (F8BT), as a probe molecule in ZnO-nanoparticle memristors. By characterizing this polymer, we can study the change of built-in potential (VBI) in the device during the resistance switching process without disturbing the resistance state by the EA probe light. Our results show that VBI increases when the device is switched to the high resistance state, suggesting a shift of effective workfunction of the electrode. Thus, we attribute the resistance switching to the field-dependent migration of oxygen vacancies associated with the adsorption and desorption of oxygen molecules at the Al/ZnO interface. This process results in the modulation of the interfacial injection barrier which governs the resistance state of the device.This work was supported by the Engineering and Physical Sciences Research Council [Grant Number EP/G060738/1]Copyright 2014 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article "Probing the switching mechanism in ZnO nanoparticle memristors" has been accepted by Journal of Applied Physics. After it is published, it will be found at http://scitation.aip.org/content/aip/journal/ja

Polarization fine-structure and enhanced single-photon emission of self-assembled lateral InGaAs quantum dot molecules embedded in a planar micro-cavity

Single lateral InGaAs quantum dot molecules have been embedded in a planar micro-cavity in order to increase the luminescence extraction efficiency. Using a combination of metal-organic vapor phase and molecular beam epitaxy samples could be produced that exhibit a 30 times enhanced single-photon emission rate. We also show that the single-photon emission is fully switchable between two different molecular excitonic recombination energies by applying a lateral electric field. Furthermore, the presence of a polarization fine-structure splitting of the molecular neutral excitonic states is reported which leads to two polarization-split classically correlated biexciton exciton cascades. The fine-structure splitting is found to be on the order of 10 micro-eV.Comment: 14 pages, 4 figures; the following article has been submitted to Journal of Applied Physics (29th ICPS - invited paper); after it is published, it will be found at http://jap.aip.org

Ecology of anthocorid (Hemipt.: Anthocoridae) predators of the pear psylla (Homopt.: Psyllidae) in the Okanagan Valley, British Columbia

The supposition is not valid that the disappearance of the native Anthocoris melanocerus from pear orchards late in the summer is because of competitive displacement by the introduced A. nemoralis. It is because A. melanocerus migrates to where prey are most abundant whereas A. nemoralis remains on pear. A. melanocerus is concentrated on willows in the spring, moves to pear when Psylla pyricola becomes abundant, and moves to cottonwood when aphids on it become abundant and the numbers of P. pyricola on pear have become low

RSPCA and the criminology of social control

This paper contributes to a rethinking of animal abuse control and animal welfare protection in criminology, specifically, and in the social sciences more broadly. We do this, first, through a broad mapping of the institutional control complex around animal abuse in contemporary Britain. Second, we focus on the institutional strategies and practices, past and present, of the main agency of animal protection, and the policing thereof, in this society, namely the Royal Society for the Prevention of Cruelty to Animals (RSPCA). In looking back to this charity’s growth since the first decades of the nineteenth century at the time of the birth of modern industrial capitalism and also to its current rationale and practices as a late-modern, corporate organisation, we explore the seeming paradox of a private body taking a lead on the regulation and prosecution of illegalities associated with animal-human relationships. Finally, the ideology and strategy of the RSPCA are explored in the context of the often visceral and culturally influential ‘morality war’ associated with proponents, respectively, of animal rights (‘abolition’) and ‘anthropic’ welfare proponents (‘regulation’ and ‘protection’)

Single and coupled L3 photonic crystal cavities for cavity-QED experiments

Here we discuss the experimental characterization of the spatial far-field profiles for the confined modes in a photonic crystal cavity of the L3 type, finding a good agreement with FDTD simulations. We then link the far-field profiles to relevant features of the cavity mode near-fields, using a simple Fabry-Perot resonator model. Finally, we describe a technique for independent all-electrical control of the wavelength of quantum dots in separated L3 cavities, coupled by a waveguide, by electrical isolation via proton implantation

Nanoscale Piezoelectric Properties of Self-Assembled Fmoc-FF Peptide Fibrous Networks

Fibrous peptide networks, such as the structural framework of self-assembled fluorenylmethyloxycarbonyl diphenylalanine (Fmoc-FF) nanofibrils, have mechanical properties that could successfully mimic natural tissues, making them promising materials for tissue engineering scaffolds. These nanomaterials have been determined to exhibit shear piezoelectricity using piezoresponse force microscopy, as previously reported for FF nanotubes. Structural analyses of Fmoc-FF nanofibrils suggest that the observed piezoelectric response may result from the noncentrosymmetric nature of an underlying β-sheet topology. The observed piezoelectricity of Fmoc-FF fibrous networks is advantageous for a range of biomedical applications where electrical or mechanical stimuli are required. © 2015 American Chemical Society