1,163 research outputs found

    The impact of lianas on tree regeneration in tropical forest canopy gaps: evidence for an alternative pathway of gap‐phase regeneration

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    1 Regeneration in forest canopy gaps is thought to lead invariably to the rapid recruitment and growth of trees and the redevelopment of the canopy. Our observations, however, suggest that an alternate successional pathway is also likely, whereby gap‐phase regeneration is dominated by lianas and stalled in a low‐canopy state for many years. We investigated gap‐phase regeneration in an old‐growth tropical forest on Barro Colorado Island (BCI) in Panama to test the following two hypotheses: (i) many gaps follow a pathway in which they remain at a low canopy height and are dominated by lianas and (ii) the paucity of trees in this pathway is a function of liana density. 2 We surveyed a total of 428 gaps of varying ages (c. 5, c. 10, and 13+ years old) and identified those which followed the conventional pathway of regeneration and others that remained stalled in a low‐canopy state for many years and were dominated by either lianas or palms. Each of these pathways will likely have different successional trajectories that will favour the growth of a distinct suite of mature species and ultimately result in contrasting species composition. 3 The successional pathway of liana‐dominated, stalled gaps is common throughout the forest. We estimate conservatively that 7.5% of the gaps that form each year will follow this pathway, probably due to the suppression of tree regeneration by lianas, and that many of these stalled gaps will persist for much longer than 13 years. Consequently, a high proportion of gaps in the forest at any given time will be stalled. Furthermore, liana tangles, which persist in the tropical forest understorey for extended periods of time, almost certainly originate in these gaps. 4 Liana abundance was positively correlated with pioneer tree abundance and diversity while negatively correlated with non‐pioneer tree abundance and diversity. Thus, lianas appear to inhibit non‐pioneer tree survival while indirectly enhancing that of pioneer trees. 5 Lianas are abundant in many types of tropical and temperate forests and a successional pathway involving liana‐dominated, stalled gaps may therefore be frequent and widespread

    'Saving the lives of our dogs': the development of canine distemper vaccine in interwar Britain

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    This paper examines the successful campaign in Britain to develop canine distemper vaccine between 1922 and 1933. The campaign mobilized disparate groups around the com- mon cause of using modern science to save the nation’s dogs from a deadly disease. Spearheaded by landed patricians associated with the country journal The Field, and funded by dog owners and associations, it relied on collaborations with veterinary professionals, government scientists, the Medical Research Council (MRC) and the commercial pharma- ceutical house the Burroughs Wellcome Company (BWC). The social organization of the campaign reveals a number of important, yet previously unexplored, features of interwar science and medicine in Britain. It depended on a patronage system that drew upon a large base of influential benefactors and public subscriptions. Coordinated by the Field Distemper Fund, this system was characterized by close relationships between landed elites and their social networks with senior science administrators and researchers. Relations between experts and non-experts were crucial, with high levels of public engagement in all aspects of research and vaccine development. At the same time, experimental and commercial research supported under the campaign saw dynamic interactions between animal and human medicine, which shaped the organization of the MRC’s research programme and demonstrated the value of close collaboration between veterinary and medical science, with the dog as a shared object and resource. Finally, the campaign made possible the translation of ‘laboratory’ findings into field conditions and commercial products. Rather than a unidirectional process, translation involved negotiations over the very boundaries of the ‘laboratory’ and the ‘field’, and what constituted a viable vaccine. This paper suggests that historians reconsider standard historical accounts of the nature of patronage, the role of animals, and the interests of landed elites in interwar British science and medicine

    Regulating Prenuptial Agreements: Balancing Autonomy and Protection

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    This thesis looks at potential future reforms for the law in relation to pre-nuptial agreements in England and Wales. Following the Supreme Court decision in Radmacher v Granatino the idea that prenuptial agreements are contrary to public policy has been well and truly discarded. With such agreements now afforded far greater recognition by the Courts, this piece looks at some potential future avenues for reform, drawing comparisons with the way the law has developed in Australia

    Carbon-13 and proton nuclear magnetic resonance analysis of shale-derived refinery products and jet fuels and of experimental referee broadened-specification jet fuels

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    A proton and carbon-13 nuclear magnetic resonance (NMR) study was conducted of Ashland shale oil refinery products, experimental referee broadened-specification jet fuels, and of related isoprenoid model compounds. Supercritical fluid chromatography techniques using carbon dioxide were developed on a preparative scale, so that samples could be quantitatively separated into saturates and aromatic fractions for study by NMR. An optimized average parameter treatment was developed, and the NMR results were analyzed in terms of the resulting average parameters; formulation of model mixtures was demonstrated. Application of novel spectroscopic techniques to fuel samples was investigated
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