My favourite nematode – Phasmarhabditis hermaphrodita

The terrestrial gastropod parasitic nematode Phasmarhabditis hermaphrodita is the only nematode that evolved to infect and kill slugs and snails. Because of this ability it has been formulated into a biological control agent for gardeners. In this Forum article, the author outlines several reasons why P. hemaphrodita is a nematode that is worth studying, including its ability to control the behaviour and kill slug hosts. The author discusses how P. hemaphrodita is being developed as a model nematode to be used to study the genetic evolution of parasitism, as well as potential research ideas for the future

Organic slug control using Phasmarhabditis hermaphrodita

Phasmarhabditis hermaphrodita is a lethal slug parasitic nematode that has been formulated into an effective biological control agent called Nemaslug®. We investigated the possibility of using different application methods of P. hermaphrodita to reduce cost and the number of nematodes applied. We also compared P. hermaphrodita with a new slug pellet called Ferramol®, which is available for use on organic farms

Steady-state negative Wigner functions of nonlinear nanomechanical oscillators

We propose a scheme to prepare nanomechanical oscillators in nonclassical steady states, characterized by a pronounced negative Wigner function. In our optomechanical approach, the mechanical oscillator couples to multiple laser driven resonances of an optical cavity. By lowering the resonance frequency of the oscillator via an inhomogeneous electrostatic field, we significantly enhance its intrinsic geometric nonlinearity per phonon. This causes the motional sidebands to split into separate spectral lines for each phonon number and transitions between individual phonon Fock states can be selectively addressed. We show that this enables the preparation of the nanomechanical oscillator in a single phonon Fock state. Our scheme can for example be implemented with a carbon nanotube dispersively coupled to the evanescent field of a state of the art whispering gallery mode microcavity

All-optical non-demolition measurement of single-hole spin in a quantum-dot molecule

We propose an all-optical scheme to perform a non-demolition measurement of a single hole spin localized in a quantum-dot molecule. The latter is embedded in a microcavity and driven by two lasers. This allows to induce Raman transitions which entangle the spin state with the polarization of the emitted photons. We find that the measurement can be completed with high fidelity on a timescale of 100 ps, shorter than the typical T2. Furthermore, we show that the scheme can be used to induce and observe spin oscillations without the need of time-dependent magnetic fields

Exciton-assisted optomechanics with suspended carbon nanotubes

We propose a framework for inducing strong optomechanical effects in a suspended carbon nanotube based on deformation potential exciton-phonon coupling. The excitons are confined using an inhomogeneous axial electric field which generates optically active quantum dots with a level spacing in the milli-electronvolt range and a characteristic size in the 10-nanometer range. A transverse field induces a tunable parametric coupling between the quantum dot and the flexural modes of the nanotube mediated by electron-phonon interactions. We derive the corresponding excitonic deformation potentials and show that this interaction enables efficient optical ground-state cooling of the fundamental mode and could allow us to realise the strong and ultra-strong coupling regimes of the Jaynes-Cummings and Rabi models.Comment: 25 pages, 2 figure

Leprosy: with special reference to its occurrence in the Protectorate of Gambia

Central Africa presents the biggest leprosy problem which the Empire has to face and must face. The extent of the disease is not yet realised nor will it be so until thorough and systematic search be made in the villages in all the colonies. A superficial count is so inaccurate and misleading as to be absolutely dangerous. Vast improvement in treatment has been made in the last decade and if full advantage of this be taken the final stamping out of leprosy is only a matter of time. Supplies of the seeds of Hydnocarpus Wightiana can now be readily procured and grow well in these tropical possessions. In five years after planting,an adequate supply of the drug would exist locally. The contagiousness of leprosy is not m,Ftter of conjecture, but of fact, and if this be realised, then a proper combating of the scourge is only possible if some form of segregation be used. Compulsory segregation at present would do no good but rather infinite harm. Segregation must be undertaken voluntarily by the natives, commencing firstly with villages and then with groups of villages. The natives would consent to do this, as they do realise the danger of the disease and understand its spread

Nonlinear nanomechanical resonators for quantum optoelectromechanics

We present a scheme for tuning and controlling nano mechanical resonators by subjecting them to electrostatic gradient fields, provided by nearby tip electrodes. We show that this approach enables access to a novel regime of optomechanics, where the intrinsic nonlinearity of the nanoresonator can be explored. In this regime, one or several laser driven cavity modes coupled to the nanoresonator and suitably adjusted gradient fields allow to control the motional state of the nanoresonator at the single phonon level. Some applications of this platform have been presented previously [New J. Phys. 14, 023042 (2012), Phys. Rev. Lett. 110, 120503 (2013)]. Here, we provide a detailed description of the corresponding setup and its optomechanical coupling mechanisms, together with an in-depth analysis of possible sources of damping or decoherence and a discussion of the readout of the nanoresonator state.Comment: 15 pages, 6 figure

The gastropod parasitic nematode Phasmarhabditis hermaphrodita does not affect non-target freshwater snails Lymnaea stagnalis, Bithynia tentaculata and Planorbarius corneus

Phasmarhabditis hermaphroditais a lethal parasite of several slug and snail species that has been formulated into a biological control agent. However, the complete host range of this nematode is poorly understood, in particular its potential to affect non-target aquatic snail species. Here we exposed three species of juvenile and adult freshwater snail ( Lymnaea stagnalis, Planorbarius corneusand Bithynia tentaculata) to 30 and 150 P. hermaphroditacm −2and assessed survival, as well as differences in weight for 66 days. We show that P. hermaphroditahas no effect on the survival of L. stagnalis, P. corneusand B. tentaculataafter 66 days of exposure. In summary, we found little evidence of P. hermaphroditacausing mortality to three freshwater snail species at two different life stages and believe that P. hermaphroditawould have little effect on non-target snail species in the wild

Relationships of Socio-demographic Characteristics and Economic Wellbeing of Women in Oklahoma with Emphasis on Poverty and Near-poor

Housing, Design and Consumer Resource