974 resultados para Robbins, John, d. 1855.


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This thesis focuses on the synthesis and analysis of novel chloride based platinum complexes derived from iminophosphine and phosphinoamide ligands, along with studies on their reactivity towards substitution and oxidation reactions. Also explored here are the potential applications of these complexes for biological and luminescent purposes. Chapter one provides an extensive overview of platinum coordination chemistry with examples of various mixed donor ligands along with the history of platinum anticancer therapy. It also looks at metals in medicine, both for biological functions as well as for therapeutic purposes and gives a background to some other applications for platinum complexes. Chapter two outlines the design and synthetic strategies employed for the development of novel platinum (II) chloride complexes from iminophosphine and phosphinoamide ligands. Also reported is the cyclometallation of these complexes to form stable tridentate mixed donor platinum (II) compounds. In Chapter three the development of a direct method for displacing a chloride from a platinum metal centre with a desired phosphine is reported. Numerous methods for successful oxidation of the platinum (II) complexes will also be explored, leading to novel platinum (IV) complexes being reported here also. The importance of stabilisation of the displaced anion, chloride, by the solvent system will also be discussed in this chapter. Chapter four investigates the reactivity of the platinum (II) complexes towards two different biomolecules to form novel platinum bio-adducts. The potential application of the platinum (II) cyclometallates as chemotherapeutics will also be explored here using in-vitro cancer cell testing. Finally, luminescence studies are also reported here for the ligands and platinum complexes reported in chapter two and three to investigate potential applications in this field also. Chapter five provides a final conclusion and an overall summary of the entire project as well as identifying key areas for future work.

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This dissertation examines how the crisis of World War I impacted imperial policy and popular claims-making in the British Caribbean. Between 1915 and 1918, tens of thousands of men from the British Caribbean volunteered to fight in World War I and nearly 16,000 men, hailing from every British colony in the region, served in the newly formed British West Indies Regiment (BWIR). Rousing appeals to imperial patriotism and manly duty during the wartime recruitment campaigns and postwar commemoration movement linked the British Empire, civilization, and Christianity while simultaneously promoting new roles for women vis-à-vis the colonial state. In Jamaica and Trinidad and Tobago, the two colonies that contributed over seventy-five percent of the British Caribbean troops, discussions about the meaning of the war for black, coloured, white, East Indian, and Chinese residents sparked heated debates about the relationship among race, gender, and imperial loyalty.

To explore these debates, this dissertation foregrounds the social, cultural, and political practices of BWIR soldiers, tracing their engagements with colonial authorities, military officials, and West Indian civilians throughout the war years. It begins by reassessing the origins of the BWIR, and then analyzes the regional campaign to recruit West Indian men for military service. Travelling with newly enlisted volunteers across the Atlantic, this study then chronicles soldiers' multi-sited campaign for equal status, pay, and standing in the British imperial armed forces. It closes by offering new perspectives on the dramatic postwar protests by BWIR soldiers in Italy in 1918 and British Honduras and Trinidad in 1919, and reflects on the trajectory of veterans' activism in the postwar era.

This study argues that the racism and discrimination soldiers experienced overseas fueled heightened claims-making in the postwar era. In the aftermath of the war, veterans mobilized collectively to garner financial support and social recognition from colonial officials. Rather than withdrawing their allegiance from the empire, ex-servicemen and civilians invoked notions of mutual obligation to argue that British officials owed a debt to West Indians for their wartime sacrifices. This study reveals the continued salience of imperial patriotism, even as veterans and their civilian allies invoked nested local, regional, and diasporic loyalties as well. In doing so, it contributes to the literature on the origins of patriotism in the colonial Caribbean, while providing a historical case study for contemporary debates about "hegemonic dissolution" and popular mobilization in the region.

This dissertation draws upon a wide range of written and visual sources, including archival materials, war recruitment posters, newspapers, oral histories, photographs, and memoirs. In addition to Colonial Office records and military files, it incorporates previously untapped letters and petitions from the Jamaica Archives, National Archives of Trinidad and Tobago, Barbados Department of Archives, and US National Archives.

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Supercontinuum generation is investigated experimentally and numerically in a highly nonlinear indexguiding photonic crystal optical fiber in a regime in which self-phase modulation of the pump wave makes a negligible contribution to spectral broadening. An ultrabroadband octave-spanning white-light continuum is generated with 60-ps pump pulses of subkilowatt peak power. The primary mechanism of spectral broadening is identified as the combined action of stimulated Raman scattering and parametric four-wave mixing. The observation of a strong anti-Stokes Raman component reveals the importance of the coupling between stimulated Raman scattering and parametric four-wave mixing in highly nonlinear photonic crystal fibers and also indicates that non-phase-matched processes contribute to the continuum. Additionally, the pump input polarization affects the generated continuum through the influence of polarization modulational instability. The experimental results are in good agreement with detailed numerical simulations. These findings demonstrate the importance of index-guiding photonic crystal fibers for the design of picosecond and nanosecond supercontinuum light sources. © 2002 Optical Society of America.

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The generation of a spatially single-mode white-light supercontinuum has been observed in a photonic crystal fiber pumped with 60-ps pulses of subkilowatt peak power. The spectral broadening is identified as being due to the combined action of stimulated Raman scattering and parametric four-wave-mixing generation, with a negligible contribution from the self-phase modulation of the pump pulses. The experimental results are in good agreement with detailed numerical simulations. These findings demonstrate that ultrafast femtosecond pulses are not needed for efficient supercontinuum generation in photonic crystal fibers. © 2001 Optical Society of America.

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info:eu-repo/semantics/published

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In the framework of the European project Platform of Local Authorities and Communicators Engaged in Science (PLACES), we analyse the articulations between scientifi c communication, public perception of science, processes of citizen participation and apropiation of space, based on a case study of the inhabitants of Teruel city, Autonomous Community of Aragon, Spain. On the interrelationships between these issues, there are a number of contradictions, such as the difference between a high interest for information about science and technology and a low level of recognition and interaction with local institutions involved in those activities, the complex conceptualization of scientifi c space in relation to the “public-private” pair, or an articulation of a claiming civic rethoric and an insuffi cient co-responsibility. We conclude that, in a local context, the dimension of territoriality and, in particular, the identifi cation with the town, is a central mediation for activating citizen participation as part of processes of appropriation of space for setting up cities of scientifi c culture.

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The joint-stock banks that established after the liberalizing legislation of 1826 were periodically criticized during the nineteenth century for their low-quality and rapidly deteriorating shareholder constituencies. The quality of a bank's shareholding constituency was of paramount importance because of unlimited shareholder liability. Using archival records, this article examines the quality of bank shareholder constituencies over the nineteenth century. The main finding is that shareholder constituencies did not deteriorate in quality until the introduction of limited liability. The non-deterioration of constituencies is attributed to bank deeds which locked in the aggregate quality of shareholder constituencies by empowering directors to vet all share transfers.

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In 1878, one of Britain's largest banks, the City of Glasgow Bank, collapsed, leaving a huge deficit between its assets and liabilities. As this bank, similar to many other contemporary British banks, had unlimited liability, its failure was accompanied by the bankruptcy of the vast majority of its stockholders. It is generally believed that the collapse of this depository institution revealed the extent to which ownership in large joint-stock banks had been diffused to investors of very modest means. It is also believed that the failure resulted in bank shareholders dumping their shares unto the market. Our evidence, garnered from ownership records, trading data, and stock prices, offers no support for these widely held beliefs. © 2007 Elsevier Inc. All rights reserved.

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The kinetics of the acid-catalysed hydrolysis of cellobiose in the ionic liquid 1-ethyl-3-methylimidazolium chloride, [C(2)mim]Cl, was studied as a model for general lignocellulosic biomass hydrolysis in ionic liquid systems. The results show that the rate of the two competing reactions, polysaccharide hydrolysis and sugar decomposition, vary with acid strength, and that for acids with an aqueous pK(a) below approximately zero, the hydrolysis reaction is significantly faster than the degradation of glucose, thus allowing hydrolysis to be performed with a high selectivity in glucose. In tests with soluble cellulose, hemicellulose (xylan), and lignocellulosic biomass (Miscanthus grass), comparable hydrolysis rates were observed with bond scission occurring randomly along the biopolymer chains, in contrast to end-group hydrolysis observed with aqueous acids.

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Using annual will indexes, a series of wealth concentration is constructed for the north of Ireland on a decennial basis for the period 1858 to 2001. Wealth was highly concentrated at the beginning of the sample period, but inequality falls towards the end of the nineteenth century and continues to fall until the 1970s. However, there does not appear to be a Kuznets-type process at work. Instead, using data on socio-occupational status, it is suggested that the fall in wealth concentration appears to be associated with the demise of the titled classes. Interestingly, similar to the findings of other studies, wealth has become more concentrated since the 1970s.