69 resultados para history of physics


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Nitrogen and phosphorus losses from the catchment of Slapton Ley, a small coastal lake in SW England, were calculated using an adaptation of a model developed by Jorgensen (1980). A detailed survey of the catchment revealed that its land use is dominated by both permanent and temporary grassland (respectively 38 and 32% of its total area), and that the remainder is made up of the cultivation of cereals and field vegetables, and market gardening. Livestock numbers in the catchment constitute ca. 6600 head of cattle, 10,000 sheep, 590 pigs, 1700 poultry and 58 horses. The permanent human population of the area is ca. 2000, served by two small gravity-fed sewage treatment works (STWs). Inputs to, and losses from, farmland in the catchment were computed using Jorgensen’s model, and coefficients derived from the data of Cooke (1976), Gostick (1982), Rast and Lee (1983) and Vollenweider (1968). Allowing for outputs from STWs, the total annual external load of N and P upon Slapton Ley is 160 t (35 kg ha-1) a-1 N, and 4.8 t (1.05 kg ha-1) a-1 P. Accordingly to Vollenweider (1968, 1975), such loadings exceed OECD permissible level by a factor of ca. 50 in the case of N, and ca. 5 in that of P. In order to reduce nutrient loads, attention would need to be paid to both STW and agricultural sources.

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Hippurate, the glycine conjugate of benzoic acid, is a normal constituent of the endogenous urinary metabolite profile and has long been associated with the microbial degradation of certain dietary components, hepatic function and toluene exposure, and is also commonly used as a measure of renal clearance. Here we discuss the potential relevance of hippurate excretion with regards to normal endogenous metabolism and trends in excretion relating to gender, age, and the intestinal microbiota. Additionally, the significance of hippurate excretion with regards to disease states including obesity, diabetes, gastrointestinal diseases, impaired renal function, psychological disorders and autism, as well as toxicity and parasitic infection, are considered.

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This paper presents a critical history of the concept of ‘structured deposition’. It examines the long-term development of this idea in archaeology, from its origins in the early 1980s through to the present day, looking at how it has been moulded and transformed. On the basis of this historical account, a number of problems are identified with the way that ‘structured deposition’ has generally been conceptualized and applied. It is suggested that the range of deposits described under a single banner as being ‘structured’ is unhelpfully broad, and that archaeologists have been too willing to view material culture patterning as intentionally produced – the result of symbolic or ritual action. It is also argued that the material signatures of ‘everyday’ practice have been undertheorized and all too often ignored. Ultimately, it is suggested that if we are ever to understand fully the archaeological signatures of past practice, it is vital to consider the ‘everyday’ as well as the ‘ritual’ processes which lie behind the patterns we uncover in the ground.

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In recent years, archives have been increasingly important to literary scholarship. Drawing upon Derrida’s description of ‘archive fever’ as an always elusive search for origins, this chapter considers the theoretical and methodological issues of reading in the publishers’ archive, questioning what this brings to our histories of the novel. Through examples drawn from the archives of two British publishers – the Hogarth Press (1917-46) and Chatto & Windus (established 1873) – focussing on Virginia Woolf’s Flush (1933) and James Hanley’s The Furys (1935), the chapter assesses the implications of bringing book history to bear on literary history.

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The origins of enterprise are often associated with the Industrial Revolution, but this article presents evidence of entrepreneurial activities from a much earlier date – the medieval period. Between 1250 and 1500 the church, merchants and members of the royal court all engaged in activities that demonstrated the entrepreneurial characteristics of innovation, risk-taking and judgement. The activities of the prior of Tynemouth and the career of the wool merchant William de la Pole illustrate these developments. By focusing on individuals rather than firms, it is possible to push back the study of entrepreneurship beyond the Industrial Revolution and early-modern trade to a period that witnessed the origins of the modern state.