17 results on '"Willis, R. J."'
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2. Approaching the Modern Era.
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Willis, R. J.
- Abstract
There was a general hiatus in interest in the chemical interaction of plants for at least a decade following about 1910. The reasons for this were twofold: 1) the work of Pickering at the Woburn Experimental Fruit Farm, and the relevant work of Whitney, Schreiner and various associates at United States Department of Agriculture, Bureau of Soils were seen as either unconvincing, unrepeatable, uneven, misinterpreted or biased, and were essentially regarded as best forgotten; and 2) events in Europe, including World War I (1914-1918), and the Russian Revolution of 1917 had farreaching effects on resources, and consequently directions and funding for agricultural and botanical research. [ABSTRACT FROM AUTHOR]
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- 2008
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3. The USDA Bureau of Soils and Its Influence.
- Author
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Willis, R. J.
- Abstract
Without doubt, the most tumultuous period in the history of allelopathy was that associated with the United States Department of Agriculture (USDA), and its Bureau of Soils, during the first two decades of the twentieth century. During this period, the academic debate on allelopathy became charged with emotion, the commentary eventually became libelous, and academic and political reputations were on the line, as were the budgets of numerous agricultural institutions and departments. [ABSTRACT FROM AUTHOR]
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- 2008
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4. Augustin Pyramus de Candolle, and His Era.
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Willis, R. J.
- Abstract
Interest in allelopathy in the first half of the nineteenth century has been linked primarily to one man, Augustin Pyramus de Candolle (Willis 1996, 2002). A.P. de Candolle (1778-1841; Figure 7.1) was born in Geneva into a moderately affluent Protestant family. At the age of seven, he was stricken with hydrocephalus, but survived seemingly with no ill affects. He became fluent in Latin while at school, and seemed destined for a literary career. The revolutionary fervour in France spread to the republic of Geneva, and de Candolle's family, being both Protestant and of privileged position, was forced to seek refuge during 1792-4 in Vaud on the shores of Lac Neuchâtel. This period was undoubtedly important for de Candolle's health, and for the development of his lifelong love of botany. [ABSTRACT FROM AUTHOR]
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- 2008
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5. Spencer Pickering, and The Woburn Experimental Fruit Farm, 1894-1921.
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Willis, R. J.
- Abstract
One of the key figures in the revival of interest in allelopathy in the twentieth century was the Englishman, S. U. Pickering (Willis 1994, 1997). Percival Spencer Umfreville Pickering1 (1858-1920; Figure 9.1) was born into an upper middle-class family, and as a youth he had the luxury of pursuing his interest in chemistry within a private laboratory at home. He eventually attended Oxford and had a relatively distinguished academic career, which culminated in an academic appointment in chemistry at Bedford College, Oxford, and ultimately in his becoming Professor of Chemistry there in 1886. In 1878 Pickering had lost his right eye, which he had initially damaged as a youth in a chemistry accident. In any case, Pickering suffered continuing poor health, and he also became disillusioned through the indifferent reception of his chemical research, which focused largely on the nature of aqueous solutions. He resigned from Bedford College in 1887, although he maintained a private interest in chemistry until about 1896. He recuperated routinely in the country at Harpenden in Hertfordshire, and to relieve any sense of idleness, he became a part-time labourer at the nearby Rothamsted Agricultural Station. He eventually decided that the lifestyle suited him, and he bought a small property in Harpenden in 1885, where he learned the rudiments of farming and horticulture, and which became his permanent home from 1902 onwards. [ABSTRACT FROM AUTHOR]
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- 2008
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6. The Decline of Allelopathy in the Latter Nineteenth Century.
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Willis, R. J.
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More or less commensurate with the death of Augustin Pyramus de Candolle in 1841, there was a groundswell of overt opposition to the root excretion theory. The reasons for this were manifold. Renewed interest in plant nutrition, led by Justus von Liebig at Giessen in Germany caused a re-examination of many of the precepts of the functioning of the root, at both an anatomical and physiological level. De Candolle had supposed that roots passively absorbed all solutes, and that the root spongioles were the active organs in this function. Since the early parts of the eighteenth century, there had been controversy about the function of the root, particularly in consideration of its structure. Moldenhawer (1820) had uniquely suggested that root exudations were not excretory in function, but occurred to assist in the absorption of food substances. Murray (1822a, 1822b) claimed that the structure of the root was not well suited to the absorption process, but was better suited for excretion. [ABSTRACT FROM AUTHOR]
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- 2008
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7. The Eighteenth Century - Root Excretion.
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Willis, R. J.
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In the first half of the eighteenth century, there were scattered advancements in the understanding of how plants grow and function. In particular relevance to the discourse here, a topic that hitherto had received little attention, namely plant excretion, became a matter of progressive conjecture during the course of the eighteenth century. [ABSTRACT FROM AUTHOR]
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- 2008
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8. What is Allelopathy?
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Willis, R. J.
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Allelopathy is widely understood as the harmful effect that one plant has on another plant due to chemicals it releases into the environment. However, unfortunately, there has been substantial variation and confusion in defining and using the term over the past fifty years (Willis 1994). [ABSTRACT FROM AUTHOR]
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- 2008
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9. Ancient India, China and Japan.
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Willis, R. J.
- Abstract
The following accounts owe little more than a related geography and a common paucity of information for their inclusion together in one chapter. As far as I know, there has been no substantial treatment in English of the early Asian literature relating to allelopathy, and doubtless much has been omitted here. Particularly in the case of China, there is a very rich body of literature of which very little has been translated into European languages. Ironically, the survival of some of these ancient documents is due to the fact that copies have found their way into Western libraries where they have been preserved, whereas native copies have perished, as for examples appears to be case with the work of the Indian writer Surapala. [ABSTRACT FROM AUTHOR]
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- 2008
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10. Arabic Works.
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Willis, R. J.
- Abstract
Following the demise of the Roman Empire, most of Europe slid into decline, into the Mediaeval period, and what is sometimes referred to as the Dark Ages. In marked contrast to this, the Arab-dominated world, which at its height in about 900 A.D. included northern Africa, Asia Minor, the Middle East, and Iberia, was ascendant. There were great advancements in mathematics, the physical sciences, astronomy, geography, and medicine, although there was an enormous debt to Greek and Roman scholarship, which the Islamic world had conserved through copies and translations. Indeed during the period spanning from the 9th through to the 12th century, more books were written in Arabic than in any other language. Despite significant advances made in the sciences noted above, there was only modest progress in botany and agriculture, which were still heavily reliant on Greek and Roman works. [ABSTRACT FROM AUTHOR]
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- 2008
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11. Allelopathy in the Classical World - Greece and Rome.
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Willis, R. J.
- Abstract
The observation that certain animals were venomous to others, and that some plants were poisonous to livestock and even humans, likely led some individuals to wonder whether some plants were actually toxic to other plants. This concept is the core of allelopathy, that is, the chemical interaction of plants, although today we also acknowledge that many plants may benefit others through the chemicals they release. In any case, the concept that one plant could poison another plant was well known to the classical authors of Greece and Rome (see Figure 2.1 for a map of the Classical world). Furthermore, the idea that one plant was inimical to another fitted comfortably within the ancient concepts of antipathy and sympathy. The literature from ancient Greece and Rome, as it concerns antipathy (Pease 1927), or more specifically allelopathy, has been broached on a few occasions (Rice 1983, Willis 1985, Aliotta and Mallik 2004, Petriccione and Aliotta 2006); however, it is the intent of this chapter to investigate this matter more fully. What emerges is that the concept of allelopathy was well known to a wide range of classical authors, and not simply those remembered for their works on natural history. [ABSTRACT FROM AUTHOR]
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- 2008
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12. Die Bodenvergiftung durch die Wurzel-Ausscheidungen der Pflanzen als vorzüglichster Grund für die Pflanzen-Wechsel-Wirthschaft - About the Book and Translator's Note.
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Willis, R. J.
- Abstract
Von Uslar's book Die Bodenvergiftung durch die Wurzel-Ausscheidungen der Pflanzen als vorzüglichster Grund für die Pflanzen-Wechsel-Wirthschaft was first published in 1844 in Altona by Georg Blatt (Figure 6). The actual printer was Gustav Osch. The original issue appeared as a book in octavo format of 166 pages, including the title leaf, corrigenda, and tailpiece. It came in a green paper wrapper, as was the custom at the time, for the cost of proper binding was at the discretion of the owner. The selling price was apparently one thaler (taler), equivalent in today's terms to perhaps about $100. However, this is very difficult to assess, as the range in wages across the spectrum of German society was much broader than today. For example a peasant farmer could earn as little as 50 thaler in a year, whereas, a university student had costs of about 1000 thaler per annum. [ABSTRACT FROM AUTHOR]
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- 2004
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13. Justus Ludewig von Uslar (1780-1862) - A Brief Biography.
- Author
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Willis, R. J.
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Surprisingly little is known about Justus Ludewig von Uslar, who is the author of what is arguably the first book devoted to allelopathy, Die Bodenvergiftung durch die Wurzel-Ausscheidungen der Pflanzen als vorzüglichster Grund für die Pflanzen- Wechsel-Wirthschaft, published in 1844. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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14. The Historical Background to Allelopathy - from Antiquity to c. 1840.
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Willis, R. J.
- Abstract
Allelopathy is a facet of plant ecology that concerns the interactions of plants as influenced by the chemical substances that they release into the air, water and soil. It engenders the fascinating idea that seemingly innocent and passive plants can engage in a form of chemical warfare, as well as selectively foster the presence of other plants. The word originates from a German publication of 1937, entitled Der Einfluss einer Pflanze auf die andere - Allelopathie, by Hans Molisch, a professor of botany in Vienna. For many, this book marks the beginning of the history of allelopathy, although in fact, most of Molisch's book deals with the effects of the gas ethylene on plants, a topic which is deemed more closely allied to plant physiology than to plant ecology. For those interested in Molisch's book, an English translation has only very recently been published (Narwal et al., 2001). [ABSTRACT FROM AUTHOR]
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- 2004
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15. National estimates of the quantity and cost of informal caregiving for the elderly with dementia.
- Author
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Langa, Kenneth M., Chernew, Michael E., Kabeto, Mohammed U., Regula Herzog, A., Beth Ofstedal, Mary, Willis, Robert J., Wallace, Robert B., Mucha, Lisa M., Straus, Walter L., Fendrick, A. Mark, Langa, K M, Chernew, M E, Kabeto, M U, Herzog, A R, Ofstedal, M B, Willis, R J, Wallace, R B, Mucha, L M, Straus, W L, and Fendrick, A M
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DEMENTIA ,ELDER care - Abstract
Objective: Caring for the elderly with dementia imposes a substantial burden on family members and likely accounts for more than half of the total cost of dementia for those living in the community. However, most past estimates of this cost were derived from small, nonrepresentative samples. We sought to obtain nationally representative estimates of the time and associated cost of informal caregiving for the elderly with mild, moderate, and severe dementia.Design: Multivariable regression models using data from the 1993 Asset and Health Dynamics Study, a nationally representative survey of people age 70 years or older (N = 7,443).Setting: National population-based sample of the community-dwelling elderly.Main Outcome Measures: Incremental weekly hours of informal caregiving and incremental cost of caregiver time for those with mild dementia, moderate dementia, and severe dementia, as compared to elderly individuals with normal cognition. Dementia severity was defined using the Telephone Interview for Cognitive Status.Results: After adjusting for sociodemographics, comorbidities, and potential caregiving network, those with normal cognition received an average of 4.6 hours per week of informal care. Those with mild dementia received an additional 8.5 hours per week of informal care compared to those with normal cognition (P < .001), while those with moderate and severe dementia received an additional 17.4 and 41.5 hours (P < .001), respectively. The associated additional yearly cost of informal care per case was 3,630 dollars for mild dementia, 7,420 dollars for moderate dementia, and 17,700 dollars for severe dementia. This represents a national annual cost of more than 18 billion dollars.Conclusion: The quantity and associated economic cost of informal caregiving for the elderly with dementia are substantial and increase sharply as cognitive impairment worsens. Physicians caring for elderly individuals with dementia should be mindful of the importance of informal care for the well-being of their patients, as well as the potential for significant burden on those (often elderly) individuals providing the care. [ABSTRACT FROM AUTHOR]- Published
- 2001
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16. © PARTIAL CHARACTERIZATION OF HAEMOLYTIC LIPIDS FROM PEROXIDIZED RAT LIVER MICROSOMES.
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WILLIS, R. J.
- Abstract
Toxic substances are generated by microsomes undergoing NADPH-dependent lipid peroxidation. In the present experiments the nature of the haemolytic material extracted from peroxidized microsomes is further examined. Suspensions of peroxidized rat liver microsomes were extracted with lipid solvents and the haemolytic material obtained subjected to get exclusion chromatography. The haemolytic activity eluted as a single broad peak with an average size of 720 daltons. There was no evidence of haemolytic compounds less than 500 daltons. On a silicic acid column the activity eluted with the phospholipid. In both separations the presence of haemolytic activity correlated well with the peroxide content. [ABSTRACT FROM AUTHOR]
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- 1982
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17. CHANGES IN LEVELS OF TISSUE NUCLEOTIDES AND GLUTATHIONE AFTER HYPERBARIC OXYGEN TREATMENT.
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Willis, R. J. and Kratzing, C. C.
- Abstract
Cites a study conducted by researchers in Australia which examines the changes in levels of tissue nucleotides and glutathione after hyperbaric oxygen treatment. Destruction of tissue constituents by autoxidation; Factors that influenced the changes in glutathione and pyridine nucleotides; Detection of the small amounts of lipid peroxide in the erythrocytes of mice.
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- 1972
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