123 research outputs found
Overexpression of the Rieske FeS protein of the Cytochrome b 6 f complex increases C4 photosynthesis in Setaria viridis.
C4 photosynthesis is characterised by a CO2 concentrating mechanism that operates between mesophyll and bundle sheath cells increasing CO2 partial pressure at the site of Rubisco and photosynthetic efficiency. Electron transport chains in both cell types supply ATP and NADPH for C4 photosynthesis. Cytochrome b 6 f is a key control point of electron transport in C3 plants. To study whether C4 photosynthesis is limited by electron transport we constitutively overexpressed the Rieske FeS subunit in Setaria viridis. This resulted in a higher Cytochrome b 6 f content in mesophyll and bundle sheath cells without marked changes in the abundances of other photosynthetic proteins. Rieske overexpression plants showed better light conversion efficiency in both Photosystems and could generate higher proton-motive force across the thylakoid membrane underpinning an increase in CO2 assimilation rate at ambient and saturating CO2 and high light. Our results demonstrate that removing electron transport limitations can increase C4 photosynthesis
A method for automatic segmentation and splitting of hyperspectral images of raspberry plants collected in field conditions
Abstract Hyperspectral imaging is a technology that can be used to monitor plant responses to stress. Hyperspectral images have a full spectrum for each pixel in the image, 400–2500 nm in this case, giving detailed information about the spectral reflectance of the plant. Although this technology has been used in laboratory-based controlled lighting conditions for early detection of plant disease, the transfer of such technology to imaging plants in field conditions presents a number of challenges. These include problems caused by varying light levels and difficulties of separating the target plant from its background. Here we present an automated method that has been developed to segment raspberry plants from the background using a selected spectral ratio combined with edge detection. Graph theory was used to minimise a cost function to detect the continuous boundary between uninteresting plants and the area of interest. The method includes automatic detection of a known reflectance tile which was kept constantly within the field of view for all image scans. A method to split images containing rows of multiple raspberry plants into individual plants was also developed. Validation was carried out by comparison of plant height and density measurements with manually scored values. A reasonable correlation was found between these manual scores and measurements taken from the images (r2 = 0.75 for plant height). These preliminary steps are an essential requirement before detailed spectral analysis of the plants can be achieved
A Range of Earth Observation Techniques for Assessing Plant Diversity
AbstractVegetation diversity and health is multidimensional and only partially understood due to its complexity. So far there is no single monitoring approach that can sufficiently assess and predict vegetation health and resilience. To gain a better understanding of the different remote sensing (RS) approaches that are available, this chapter reviews the range of Earth observation (EO) platforms, sensors, and techniques for assessing vegetation diversity. Platforms include close-range EO platforms, spectral laboratories, plant phenomics facilities, ecotrons, wireless sensor networks (WSNs), towers, air- and spaceborne EO platforms, and unmanned aerial systems (UAS). Sensors include spectrometers, optical imaging systems, Light Detection and Ranging (LiDAR), and radar. Applications and approaches to vegetation diversity modeling and mapping with air- and spaceborne EO data are also presented. The chapter concludes with recommendations for the future direction of monitoring vegetation diversity using RS
Stylometry and the Defoe canon: a reply to Irving Rothman
In PBSA (94 (2000), pp. 375-98) Irving Rothman attacked P.N. Furbank and W.R. Owens for their work on the Defoe attribution problem, arguing that they had not paid sufficient attention to the stylometric work of Stieg Hargevik (published in 1962). This article is a rejoinder to Rothman, arguing that he has not grasped the fundamental principle that it is not necessary to prove a negative: in other words, where no good reason has ever been put forward for attributing a work to Defoe, that work has no right to a place in the 'canon' of his works. Hargevik's early attempt at a 'stylometric' method of attributing works to Defoe was deeply flawed, and provides no reason for believing that works tested under his method should be regarded as by Defoe
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Defoe and the sham Flying-Post
This article explores the complicated story of Defoe's involvement with William Hurt in the publication of a rival, imitation edition of George Ridpath's journal, The Flying-Post, or, The Post-Master, which appeared under the title The Flying-Post and Medley (subsequently shortened to The Flying-Post) from July to September 1714
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William Lee of Sheffield: Sanitary Reformer and Defoe Bibliographer
This article presents a biographical account of the leading Defoe scholar of the nineteenth century, William Lee, who added over sixty works to the canon of Defoe's writings, as well as a mass of journalism never before attributed to him. It argues Lee's understanding of Defoe was limited and that each of his attributions needs careful and unprejudiced re-examination before they can be accepted
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Defoe and A Curious Little Oration Deliver'd by Father Andrew
Argues that a pamphlet of 1717, entitled 'A Curious Little Oration . . . Translated from the Fourth Edition of the French, by Dan. De F-e', was not, as implied by the bibliographer J.R. Moore an original production by Defoe. Cites the existence in the Bodleian Library of a brief undated tract in French which corresponds closely, and in places word for word, with the Curious Little Oration
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On the attribution of periodicals and newspapers to Daniel Defoe
A study of some twenty-seven periodicals and newspapers listed by J.R. Moore in his Checklist of Defoe's Writings as ones to which Defoe contributed. Argues that in the case of seventeen of these periodicals there is no solid evidence that Defoe ever wrote for them, and that they should therefore not be included in the canon of his writings
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A political biography of Daniel Defoe
A detailed biographical account of Defoe's political activities, as journalist, polemicist, political theorist and government agent, putting forward a radically new interpretation of some aspects of his tangled political career.
In this new book, Furbank and Owens attempt to disentangle the story of Daniel Defoe’s political career, as journalist, polemicist, political theorist and secret agent. They argue that this remarkable career calls for a good deal of rethinking, not least because biography and bibliography are here inextricably intertwined. The book challenges the current account of Defoe’s political career – rather drastically in some cases. It argues, for example, that Defoe’s cherished story of his intimacy with King William – a staple of all previous Defoe biographies – was most probably an (immensely bold) fiction, a view which, if correct, entails considerable revision of his personality and career. Likewise, it offers a bold new interpretation of the famous series of letters Defoe wrote in 1718 to his Government paymaster, the Whig Undersecretary of State Charles de la Faye, in which he describes how he insinuated himself into the management of a number of opposition Tory journals to restrain and ‘enervate’ them. Modern biographers have taken these extraordinary letters at face value, constructing their accounts of Defoe’s later political career around them. By contrast, Furbank and Owens argue that they represented, instead, a dazzling piece of mendacity. If Defoe was deceiving anybody it was his Whig paymasters
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Defoe and the Dutch Alliance: some attributions examined
A study of six pamphlets on the peace-negotiations of 1710-1712 previously attributed to Daniel Defoe, arguing that only three can safely be attributed to him
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