133,184 research outputs found
Measurement of ATP in soil: correcting for incomplete recovery
No full textMartens [Soil Biol. Biochem. 33 (2001) 701] recently reported that Jenkinson and Oades [Soil Biol. Biochem. II (1979) 193] method for measuring adenosine 5′ triphosphate (ATP) in soil leads to serious underestimations. We have now compared the Jenkinson and Oades extraction technique, which corrects for incomplete extraction of ATP by reference to a 'spike' of added ATP, with a sequential extraction procedure as used by Martens. Measurements of the ATP contents of four soils by the two procedures showed no significant differences, in contrast to Martens' finding
David Stewart Jenkinson. 25 February 1928 — 16 February 2011
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David Jenkinson was one of the most influential soil scientists of his generation, bringing new insights into the transformations of organic matter and nitrogen in soil. He spent the majority of his career at Rothamsted Research, Harpenden, UK. His studies were influential regarding the role of soil carbon stocks in the context of climate change and the role of nitrogen fertilizer in delivering adequate supplies of food for a growing world population. His research encompassed both fundamental studies on soil processes and immensely practical applications of this knowledge, often utilizing the Rothamsted long-term experiments that have run for over 170 years. He is particularly well known for his development of a method for determining the quantity of organic carbon held in the cells of living micro-organisms in soil, termed the ‘soil microbial biomass’. This breakthrough opened the way for a new wave of soil biological research. David developed one of the earliest computer models for the turnover of organic carbon in soil, known as the Rothamsted Carbon Model, RothC. This model, conceptually very simple, has proved highly successful in simulating and predicting changes in soil organic carbon (SOC) content under different management practices worldwide, being used by over 2600 people in 115 countries. His research using the stable isotope of nitrogen,
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N, in large-scale field experiments drew attention to the factors leading to inefficiencies in the use of nitrogen fertilizer but also demonstrated that it is possible to achieve high efficiency if good agricultural management practices are followed. It also demonstrated, more clearly than previously, the great importance of soil organic matter as a source of nitrogen for crops and the role of the soil microbial biomass both in immobilizing a proportion of applied fertilizer nitrogen and also in causing confusion in the interpretation of such experiments. By calculating nitrogen budgets for the Rothamsted long-term experiments he quantified the deposition of nitrogen compounds from atmosphere to land, laying foundations for later studies concerning the ecological and agricultural impacts of this significant input of nitrogen.
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Competition in regulated industries
No full textEleven papers analyze and draw some preliminary lessons from the British experience in introducing competition into regulated industries. Part 1 provides an overview, discussing regulation, competition, and the structure of prices and network industries. Part 2 focuses on the electricity industry in England and Wales and U.K. experiences with the introduction of competition in the gas industry, telecommunications, the water industry, and the rail industry. Part 3 provides the regulators' perspective on the generation and supply of electricity, the regulation of telecommunications, competition in the water and sewerage industry, and competition in the rail industry. Contributors are mainly economists and some are regulators. Helm is at New College, Oxford. Jenkinson is at the University of Oxford and at Keble College. Bibliography; index
Competition in regulated industries
No full textEleven papers analyze and draw some preliminary lessons from the British experience in introducing competition into regulated industries. Part 1 provides an overview, discussing regulation, competition, and the structure of prices and network industries. Part 2 focuses on the electricity industry in England and Wales and U.K. experiences with the introduction of competition in the gas industry, telecommunications, the water industry, and the rail industry. Part 3 provides the regulators' perspective on the generation and supply of electricity, the regulation of telecommunications, competition in the water and sewerage industry, and competition in the rail industry. Contributors are mainly economists and some are regulators. Helm is at New College, Oxford. Jenkinson is at the University of Oxford and at Keble College. Bibliography; index
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Thomas Jenkinson Woodward, Bungay, [Suffolk], to James Edward Smith, 12 Great Marlborough Street, London
No full textDetails of his journey and pending visit to London. Expects [Charles] Bryant [(d 1799)] to be "very angry" on reading his paper [on 'Lycoperdons'], expects an attack in the "Gentleman's Magazine". Saw the attack on Smith's 'Geranium lucidum' of "English botany" in "Gentleman's Magazine"; unsure who the author is and attempts to apologise for him. Approves of "English botany" including cryptogams but warns against figuring too many for fear of "disgusting the florists & the ladies". Hopes to send [James] Sowerby 'Cineraria palustris' and others from Yarmouth; doubts whether the drawing of 'Agaric' is the 'Clypeolarias' of Bulliard, as [William] Withering refers to it. Visits from Sir John Rous [1st Earl of Stradbroke (1750-1827), politician] who grows exotic trees in his plantations, does not study them scientifically but knows their names in "Hortus Kewensis"
Thomas Jenkinson Woodward, Bungay, [Suffolk], to James Edward Smith, 12 Great Marlborough Street, London
No full textDetails of his journey and pending visit to London. Expects [Charles] Bryant [(d 1799)] to be "very angry" on reading his paper [on 'Lycoperdons'], expects an attack in the "Gentleman's Magazine". Saw the attack on Smith's 'Geranium lucidum' of "English botany" in "Gentleman's Magazine"; unsure who the author is and attempts to apologise for him. Approves of "English botany" including cryptogams but warns against figuring too many for fear of "disgusting the florists & the ladies". Hopes to send [James] Sowerby 'Cineraria palustris' and others from Yarmouth; doubts whether the drawing of 'Agaric' is the 'Clypeolarias' of Bulliard, as [William] Withering refers to it. Visits from Sir John Rous [1st Earl of Stradbroke (1750-1827), politician] who grows exotic trees in his plantations, does not study them scientifically but knows their names in "Hortus Kewensis"
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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