Single-shot measurement of quantum optical phase

Although the canonical phase of light, which is defined as the complement of photon number, has been described theoretically by a variety of distinct approaches, there have been no methods proposed for its measurement. Indeed doubts have been expressed about whether or not it is measurable. Here we show how it is possible, at least in principle, to perform a single-shot measurement of canonical phase using beam splitters, mirrors, phase shifters and photodetectors.Comment: This paper was published in PRL in 2002 but, at the time, was not placed on the archive. It is included now to make accessing this paper easie

Host range of the ginger strain of Pseudomonas solanacearum in Queensland

The host range of Pseudomonas solanacearum biotype 4, the strain responsible for a rapid wilt of ginger, was found to include tomato, potato, capsicum, egg plant, peanut, tobacco, Solanum nigrum, Physalis minima, P. peruviana, and Solanm mauritianum. During the summer months of 1967-68 and 1969-70, weeds growing in bacterial wilt affected ginger plantings were examined for the presence of P. solanacearum. Biotype 4 was isolated from S. nigrum, Crassocephalum crepidioides, S. mauritianum, P. minima, P. peruviana, and Ageratum houstonianum. Biotype 3, the strain commonly found in the ginger growing district of southern Queensland was isolated from S. nigrum, C. crepidioides, S. mauritianum, Xanthium pungens, Dodonaea lanceolata, Bidens pilosa, and Sida spinosa. These weeds were all collected from ginger fields. It appears from these results and previous observations that biotype 4 has a more restricted and slightly different host range from biotype 3. Consequently it has been suggested that in any crop rotation, ginger growers should eliminate known biotype 4 susceptible weeds. Both biotypes 4 and 3 survived, in the experimental plots, a 20-month period of severe drought during 1968-69. However, no attempt was made to control weed growth in the trial area

The fundamental cycle of concept construction underlying various theoretical frameworks

In this paper, the development of mathematical concepts over time is considered. Particular reference is given to the shifting of attention from step-by-step procedures that are performed in time, to symbolism that can be manipulated as mental entities on paper and in the mind. The development is analysed using different theoretical perspectives, including the SOLO model and various theories of concept construction to reveal a fundamental cycle underlying the building of concepts that features widely in different ways of thinking that occurs throughout mathematical learning

Resistance to Digitisation: Curated Memory Cards Artefact

date-added: 2015-03-24 04:16:59 +0000 date-modified: 2015-03-24 04:16:59 +0000date-added: 2015-03-24 04:16:59 +0000 date-modified: 2015-03-24 04:16:59 +0000The act of networking in any context has some element of ceremonial performance attached to it. In an analogue world these performances have historically included the act of exchanging business cards. This ‘ceremony of networking’ has the potential to be altered by the emergence of new media, especially digital technology, displacing the old ceremony of business card exchanges and disrupting what can traditional be seen as networking. The history of business cards have shown that, despite several digital alternatives, they are still resistant to digitisation and so predominantly still physical and tangible. So, we sought to explore the ceremony around giving business cards as the sharing of ‘curated memory’, to better understand how and why we share and co-create curated memories with others. Including the sharing curated memories more generally, and the changing nature of networking, arising from the ever-increasing connectivity and digital embeddedness associated with the information age. Therefore, exploring the ceremony around needing, creating, sharing and using business cards, within different contexts and cultures. Also, identifying the tasks that people are trying to perform and optimise at different stages (before, during, and after) in a range of scenarios. Also, to explore how the ceremonies of networking might be significantly altered as a result of digital media and tools. The approach of using sets of cards around Who, How, Why and Where emerged from the need for a tool that could build narratives around the considerable diversity of the disjointed scenarios of networking we observed. So, the cards provide a reference by which to share general understanding in an entertaining and easily accessible manner. Second, provides a tool to summarise narratives from the scenarios we observed, and that we could then use to create new scenarios to explore insights such as post-meeting curation of ‘shared memories’ when networking. Third, define a number of ‘games’ to help anyone explore how to better understand and utilise aspects of networking in their current approaches, and challenge them to develop new approaches. Therefore, generating debate and self-reflection on the ways players use business cards themselves

Heart rot of Australian pineapples caused by Dickeya zeae

Pineapple plants (hybrid MD2) with bacterial heart rot were detected in a commercial plantation at Glasshouse Mountains, Queensland, in November 2015. The bacterial strain BRIP64263 isolated from infected tissue was shown to be a Gram negative soft-rotting bacterium capable of growth at 41 ºC, and based on its culture properties was provisionally identified as Dickeya. This strain was compared with other putative Dickeya strains affecting banana (BRIP64262) and potato (BRIP29490). Sequence analysis of the recombinase A genes of the pineapple strain placed it in phylotype I of D. zeae, whereas the banana strain was placed in phylotype II. This was confirmed by sequence comparisons for the phosphofructose kinase, RNA polymerase and aconitase genes which showed that the pineapple strain BRIP64263 is distinct from other strains that infect pineapples and other hosts in Australia and overseas. Furthermore, phylogenetic analysis of the replication initiation factor gene showed that strains affecting pineapples were distributed among both phylotypes of D. zeae, indicating multiple acquisitions or opportunistic infections of pineapple from this group of pathogens. The potato isolate, BRIP29490, was shown to be Rahnella aquatica, and is not likely to be pathogenic. It is not known whether the new isolate represents an incursion or whether it has long been associated with pineapples in Australia. Further study is required to determine the epidemiological characteristics of this strain, and what threat it poses to Australian pineapple production

Retrodiction with two-level atoms: atomic previvals

In the Jaynes-Cummings model a two-level atom interacts with a single-mode electromagnetic field. Quantum mechanics predicts collapses and revivals in the probability that a measurement will show the atom to be excited at various times after the initial preparation of the atom and field. In retrodictive quantum mechanics we seek the probability that the atom was prepared in a particular state given the initial state of the field and the outcome of a later measurement on the atom. Although this is not simply the time reverse of the usual predictive problem, we demonstrate in this paper that retrodictive collapses and revivals also exist. We highlight the differences between predictive and retrodictive evolutions and describe an interesting situation where the prepared state is essentially unretrodictable.Comment: 15 pages, 3 (5) figure

Heart rot of Australian pineapples caused by Dickeya zeae

Pineapple plants (hybrid MD2) with bacterial heart rot were detected in a commercial plantation at Glasshouse Mountains, Queensland, in November 2015. The bacterial strain BRIP64263 isolated from infected tissue was shown to be a Gram negative soft-rotting bacterium capable of growth at 41 ºC, and based on its culture properties was provisionally identified as Dickeya. This strain was compared with other putative Dickeya strains affecting banana (BRIP64262) and potato (BRIP29490). Sequence analysis of the recombinase A genes of the pineapple strain placed it in phylotype I of D. zeae, whereas the banana strain was placed in phylotype II. This was confirmed by sequence comparisons for the phosphofructose kinase, RNA polymerase and aconitase genes which showed that the pineapple strain BRIP64263 is distinct from other strains that infect pineapples and other hosts in Australia and overseas. Furthermore, phylogenetic analysis of the replication initiation factor gene showed that strains affecting pineapples were distributed among both phylotypes of D. zeae, indicating multiple acquisitions or opportunistic infections of pineapple from this group of pathogens. The potato isolate, BRIP29490, was shown to be Rahnella aquatica, and is not likely to be pathogenic. It is not known whether the new isolate represents an incursion or whether it has long been associated with pineapples in Australia. Further study is required to determine the epidemiological characteristics of this strain, and what threat it poses to Australian pineapple production