1,950 research outputs found
Acid-adaption by a medic microsymbiont: new insights from the genome of Sinorhizobium medicae WSM419
The poor availability of nitrogen is one of the principal factors limiting global biomass. Legumes are vital components of agricultural systems because of their ability to associate symbiotically with root nodule bacteria (RNB) and subsequently fix atmospheric nitrogen to a form that can be utilised by the plant partner. Furthermore, this symbiotic relationship provides available soil nitrogen for subsequent non-leguminous crops. This RNB-legume interaction is affected by a number of environmental factors. Progressive acidification of agricultural soils is one of the big challenges in agriculture as soil acidity negatively impacts legume productivity. One genus of RNB, Sinorhizobium, is particularly acid-sensitive causing a major reduction in Medicago productivity in acidic soils. Due to the importance of Medic pasture production, alternative strains have been captured, and are still being captured, from the genetic pool that display superior acid tolerance characteristics. This presentation will focus on the acid-tolerant species S. medicae (previously known as S. meliloti) and in particular on the previously used commercial inoculant WSM419
All-Optical Production of a Degenerate Fermi Gas
We achieve degeneracy in a mixture of the two lowest hyperfine states of
Li by direct evaporation in a CO laser trap, yielding the first
all-optically produced degenerate Fermi gas. More than atoms are
confined at temperatures below K at full trap depth, where the Fermi
temperature for each state is K. This degenerate two-component mixture
is ideal for exploring mechanisms of superconductivity ranging from Cooper
pairing to Bose condensation of strongly bound pairs.Comment: 4 pgs RevTeX with 2 eps figs, to be published in Phys. Rev. Let
Dealing with mobility: Understanding access anytime, anywhere
The rapid and accelerating move towards the adoption and use of mobile technologies has increasingly provided people and organisations with the ability to work away from the office and on the move. The new ways of working afforded by these technologies are often characterised in terms of access to information and people ‘anytime, anywhere’. This paper presents a study of mobile workers that highlights different facets of access to remote people and information, and different facets of anytime, anywhere. Four key factors in mobile work are identified from the study: the role of planning, working in ‘dead time’, accessing remote technological and informational resources, and monitoring the activities of remote colleagues. By reflecting on these issues, we can better understand the role of technology and artefact use in mobile work and identify the opportunities for the development of appropriate technological solutions to support mobile workers
A path-independent approach to integrated variance under the CEV model
In this paper, a closed form path-independent approximation of the fair variance strike for a variance swap under the constant elasticity of variance (CEV) model is obtained by applying the small disturbance asymptotic expansion. The realized variance is sampled continuously in a risk-neutral market environment. With the application of a Brownian bridge, we derive a theorem for the conditionally expected product of a Brownian motion at two different times for arbitrary powers. This theorem enables us to provide a conditional Monte-Carlo scheme for simulating the fair variance strike. Compared with results in the recent literature, the method outlined in our paper leads to a simplified approach for pricing variance swaps. The method may also be applied to other more sophisticated volatility derivatives. An empirical comparison of this model with the Heston model and a conditional Monte Carlo scheme is also presented using option data on the S&P 500
PSS23 Patient Burden Associated With Lack of Treatment Satisfaction Amongst Psoriasis Patients Receiving Traditional Systemic Therapies
The Parliamentary Commissioner for Administration, the Foreign Office and the Sachsenhausen case, 1964–1968
This communication follows the evolution, reception, and implications of the parliamentary commissioner's critical 1968 report on Foreign Office ‘maladministration’ regarding compensation for British concentration camp inmates. It explores officials' and ministers' attitude to the investigative techniques associated with this new office, as well as their hostile reaction to the publicity and parliamentary controversy to which his work gave rise. It concludes by exploring the wider implications of the case, especially the inherent problems faced by governments seeking closer and more harmonious relationships with the governed
New histories of British imperial communications and the "networked world" of the nineteenth and early twentieth centuries
A number of recent histories of Britain’s late-19th century telegraph network have taken inspiration from many sources, not least historians’ concern to test and delineate the contemporary and modern world of transnational policymaking, the return of maritime history to the forefront of historical studies, and the desire to understand the late 19th century empire that seemed to be drawing strength from technological progress. But another key reason for this new interest in the electric telegraph is clearly the communications revolution of the last 20 years, and the internet’s development as the main means of dealing with information in the modern world. This article demonstrates just how important this present-mindedness has been, but it also shows just how unlike the internet was the Victorian telegraph system, for it was expensive, patchy and often unreliable, encouraging letter-writing and ship-borne commerce just as much as electronic communication. The telegraph’s inauguration reinforced local and imperial nationalisms and rivalries, and arms races, whatever the liberal hopes invested in it; its arrival often led to the concentration of press ownership and a sense of intra-imperial, rather than global or trans-continental, links. The example of the telegraph, it is contended, should form a cautionary example of how problematical it is to take present-day developments and apply them – even as organising concepts – to the past
Britain and the sea since 1600
In this first full-scale treatment of Britain's relationship with the surrounding oceans, Glen O'Hara examines the history of British people's maritime lives and, in turn, the formation of British cultural identities. A lens through which to view British life, Britain and the Sea spans more than 400 years, beginning in 1600 and taking us through to the present day. Tying together every aspect in the development of Great Britain, from state formation, industrialization and modernization, through to histories of transport, migration, slavery, warfare and crime, this book illustrates how the rich tapestry of Britain's narrative was decided not among the fields of the 'green and pleasant land', but out at sea
Bradyrhizobium cenepequi sp. nov., Bradyrhizobium semiaridum sp. nov., Bradyrhizobium hereditatis sp. nov. and Bradyrhizobium australafricanum sp. nov., symbionts of different leguminous plants of Western Australia and South Africa and definition of three novel symbiovars
Bradyrhizobium is a heterogeneous bacterial genus capable of establishing symbiotic associations with a broad range of legume hosts, including species of economic and environmental importance. This study was focused on the taxonomic and symbiovar definition of four strains – CNPSo 4026T, WSM 1704T, WSM 1738T and WSM 4400T – previously isolated from nodules of legumes in Western Australia and South Africa. The 16S rRNA gene phylogenetic tree allocated the strains to the Bradyrhizobium elkanii supergroup. The multilocus sequence analysis (MLSA) with partial sequences of six housekeeping genes – atpD, dnaK, glnII, gyrB, recA and rpoB – did not cluster the strains under study as conspecific to any described Bradyrhizobium species. Average nucleotide identity and digital DNA–DNA hybridization values were calculated for the four strains of this study and the closest species according to the MLSA phylogeny with the highest values being 95.46 and 62.20 %, respectively; therefore, both being lower than the species delineation cut-off values. The nodC and nifH phylogenies included strains WSM 1738T and WSM 4400T in the symbiovars retamae and vignae respectively, and also allowed the definition of three new symbiovars, sv. cenepequi, sv. glycinis, and sv. cajani. Analysis of morphophysiological characterization reinforced the identification of four novel proposed Bradyrhizobium species that are accordingly named as follows: Bradyrhizobium cenepequi sp. nov. (CNPSo 4026T=WSM 4798T=LMG 31653T), isolated from Vigna unguiculata; Bradyrhizobium semiaridum sp. nov. (WSM 1704T=CNPSo 4028T=LMG 31654T), isolated from Tephrosia gardneri; Bradyrhizobium hereditatis sp. nov. (WSM 1738T=CNPSo 4025T=LMG 31652T), isolated from Indigofera sp.; and Bradyrhizobium australafricanum sp. nov. (WSM 4400T=CNPSo 4015T=LMG 31648T) isolated from Glycine sp
Pricing Extendible Options Using the Fast Fourier Transform
This paper applies the fast Fourier transform (FFT) approach, within the Black-Scholes framework, to the valuation of options whose time to maturity can be extended to a future date (extendible options). We determine the valuation of the extendible options as sums of expectations of indicator functions, leading to a semianalytic expression for the value of the options over a range of strikes. Compared to Monte Carlo simulation, numerical examples demonstrate that the FFT is both computationally more efficient and higher in accuracy.</jats:p
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