Learning to live with clover scorch

Recent research has increased our understanding of clover scorch disease in Western Australia. An economic control has yet to be developed but it appears that management can be adjusted to reduce damage to pastures and there is scope for using resistant species and less susceptible cultivars to escape the disease. A major research programme is in progress

Single-photon entanglement generation by wavefront shaping in a multiple-scattering medium

We demonstrate the control of entanglement of a single photon between several spatial modes propagating through a strongly scattering medium. Measurement of the scattering matrix allows the wavefront of the photon to be shaped to compensate the distortions induced by multiple scattering events. The photon can thus be directed coherently to a single or multi-mode output. Using this approach we show how entanglement across different modes can be manipulated despite the enormous wavefront disturbance caused by the scattering medium.Comment: 4 pages, 3 figures, reference adde

Progress in clover scorch research

Considerable progress has been made with the clover scorch problem since the devastation of the 971 epidemic when intensive research began. Over 2000 varieties and crossbreds of subterranean clover from various collections have been screened for resistance resulting in the release of the first resistant clover, Esperance, this year. Benefits of fungicidal spraying have been demonstrated and low cost spraying programmes for grazed pastures, and seed and hay crops are under field investigation

Ultra scale-down approaches to enhance the creation of bioprocesses at scale: impacts of process shear stress and early recovery stages

The sensitivity of biological materials to shear stress conditions encountered during large-scale bioprocessing makes successful scale up from the bench challenging. Ultra scale-down technologies seek to use just millilitre quantities to enhance our understanding of the impact of the process environment as a basis for process optimisation. They can help speed translation of new biological discoveries to market and reduce risks encountered in scale up. They are important both as process discovery tools and as preparative tools to yield material for study of subsequent stages. In this review the focus is on the early recovery stages post fermentation or cell culture and in particular the use of continuous-flow and dead-end centrifugation integrated with preparative stages (e.g. flocculation) and subsequent depth filtration. Examples range from therapeutic antibodies, to rationally engineered (synthetic biology) host strains, to stem cells for therapy

Laser-induced electron emission from a tungsten nanotip: identifying above threshold photoemission using energy-resolved laser power dependencies

We present an experiment studying the interaction of a strongly focused 25 fs laser pulse with a tungsten nanotip, investigating the different regimes of laser-induced electron emission. We study the dependence of the electron yield with respect to the static electric field applied to the tip. Photoelectron spectra are recorded using a retarding field spectrometer and peaks separated by the photon energy are observed with a 45 % contrast. They are a clear signature of above threshold photoemission (ATP), and are confirmed by extensive spectrally resolved studies of the laser power dependence. Understanding these mechanisms opens the route to control experiment in the strong-field regime on nanoscale objects.Comment: 9 pages, 6 figure

Ryegrass toxicity organism found on other grasses

Yellow slime disease caused by Corynebacterium sp. has recently been found in three grass species. The diseased grasses were found in the field growing with each other and with affected toxic annual ryegrass

Evaluation of options for harvest of a recombinant E. coli fermentation producing a domain antibody using ultra scale-down techniques and pilot-scale verification

Ultra scale-down (USD) methods operating at the millilitre scale were used to characterise full-scale processing of E. coli fermentation broths autolysed to different extents for release of a domain antibody. The focus was on the primary clarification stages involving continuous centrifugation followed by depth filtration. The performance of this sequence was predicted by USD studies to decrease significantly with increased extents of cell lysis. The use of polyethyleneimine (PEI) reagent was studied to treat the lysed cell broth by precipitation of soluble contaminants such as DNA and flocculation of cell debris material. The USD studies were used to predict the impact of this treatment on the performance and here it was found that the fermentation could be run to maximum productivity using an acceptable clarification process (e.g a centrifugation stage operating at 0.11 L per m(2) equivalent gravity settling area per h followed by a resultant required depth filter area of 0.07 m(2) per L supernatant). A range of USD predictions was verified at the pilot scale for centrifugation followed by depth filtration. This article is protected by copyright. All rights reserved

A pump-probe study of the formation of rubidium molecules by ultrafast photoassociation of ultracold atoms

An experimental pump-probe study of the photoassociative creation of translationally ultracold rubidium molecules is presented together with numerical simulations of the process. The formation of loosely bound excited-state dimers is observed as a first step towards a fully coherent pump-dump approach to the stabilization of Rb$_2$ into its lowest ground vibrational states. The population that contributes to the pump-probe process is characterized and found to be distinct from a background population of pre-associated molecules.Comment: Accepted for publication in Phys. Rev. A (10 pages, 9 figures