834 resultados para unicellular and colonial Microcystis
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The diversification of life involved enormous increases in size and complexity. The evolutionary transitions from prokaryotes to unicellular eukaryotes to metazoans were accompanied by major innovations inmetabolicdesign.Hereweshowthat thescalingsofmetabolic rate, population growth rate, and production efficiency with body size have changed across the evolutionary transitions.Metabolic rate scales with body mass superlinearly in prokaryotes, linearly in protists, and sublinearly inmetazoans, so Kleiber’s 3/4 power scaling law does not apply universally across organisms. The scaling ofmaximum population growth rate shifts from positive in prokaryotes to negative in protists and metazoans, and the efficiency of production declines across these groups.Major changes inmetabolic processes duringtheearlyevolutionof life overcameexistingconstraints, exploited new opportunities, and imposed new constraints. The 3.5 billion year history of life on earth was characterized by
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This article examines the intertextual relationship between Marguerite Duras' pro-colonialist, propagandist text, L'Empire français (1943), and her seemingly anti-colonialist novel, Un barrage contre le Pacifique (1950). It explores both the transformative and the emulative uses to which descriptive elements, borrowed from the precursor text, are put in the novel's depictions of colonial Indochina. Going against prevalent critical readings of Barrage, the article highlights the ambivalent and ultimately only partial nature of Duras' apparent ideological volte-face
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Countries throughout the sub-Saharan (SSA) region have a complex linguistic heritage having their origins in opportunistic boundary changes effected by Western colonial powers at the Berlin Conference 1884-85. Postcolonial language-in-education policies valorizing ex-colonial languages have contributed at least in part to underachievement in education and thus the underdevelopment of human resources in SSA countries. This situation is not likely to improve whilst unresolved questions concerning the choice of language(s) that would best support social and economic development remain. Whilst policy attempts to develop local languages have been discussed within the framework of the African Union, and some countries have experimented with models of multilingual education during the past decade, the goalposts have already changed as a result of migration and trade. This paper argues that language policy makers need to be cognizant of changing language ecologies and their relationship with emerging linguistic and economic markets. The concept of language, within such a framework, has to be viewed in relation to the multiplicity of language markets within the shifting landscapes of people, culture, economics and the geo-politics of the 21st Century. Whilst, on the one hand, this refers to the hegemony of dominant powerful languages and the social relations of disempowerment, on the other hand, it also refers to existing and evolving social spaces and local language capabilities and choices. Within this framework the article argues that socially constructed dominant macro language markets need to be viewed also in relation to other, self-defined, community meso- and individual micro- language markets and their possibilities for social, economic and political development. It is through pursuing this argument that this article assesses the validity of Omoniyi’s argument in this volume, for the need to focus on the concept of language capital within multilingual contexts in the SSA region as compared to Bourdieu’s concept of linguistic capital.
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The quality of a country’s human-resource base can be said to determine its level of success in social and economic development. This study focuses on some␣of the major human-resource development issues that surround the implementation of South Africa’s policy of multilingualism in education. It begins by discussing the relationship between knowledge, language, and human-resource, social and economic development within the global cultural economy. It then considers the situation in South Africa and, in particular, the implications of that country’s colonial and neo-colonial past for attempts to implement the new policy. Drawing on the linguistic-diversity-in-education debate in the United Kingdom of the past three decades, it assesses the first phase of an in-service teacher-education programme that was carried out at the Project for Alternative Education in South Africa (PRAESA) based at the University of Cape Town. The authors identify key short- and long-term issues related to knowledge exchange in education in multilingual societies, especially concerning the use of African languages as mediums for teaching and learning.
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This paper juxtaposes postmodernist discourses on language, identity and cultural power with historical forms of language inequalities grounded in the nation-state. The discussion is presented in three sections. The first section focuses on the mixed legacies of language-state relations within the pluralist nation-state, colonial and postcolonial language policies. The second section examines the concept of linguistic minority rights beyond the nation-state. This incorporates discussion of transmigration, the breaking up of previous power blocs in Eastern Europe and the role of language in the articulation of emergent 'ethnic' nationalisms. The third section examines the concept of multilingualism within the interactive cultural landscape defined by 'informationalism'. Discussing the collective impact of these variables on the shaping of new cultural, economic and political inequalities, the paper highlights the tensions in which the concept of linguistic minority rights exists in the world today.
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This piece is a contribution to the exhibition catalogue of Barbadian / Canadian artist Joscelyn Gardner's exhibition, 'Bleeding & Breeding' curated by Olexander Wlasenko, January 14-February 12, 2012 in the Station Gallery, Whitby, Ontario, Canada. The piece examines the ways in which Gardner's Creole Portraits II (2007) and Creole Portraits III (2009) issue a provocative and carefully crafted contestation to the journals of the slave-owner and amateur botanist Thomas Thistlewood. It argues that while Thistlewood’s journals make raced and gendered bodies seemingly available to knowledge, incorporating them within the colonial archive as signs of subjection, Gardener’s portraits disrupt these acts of history and knowledge. Her artistic response marks a radical departure from the significant body of scholarship that has drawn on the Thistlewood journals to date. Creatively contesting his narratives’ dispossession of Creole female subjects and yet aware of the problems of innocent recovery, her works style representations that retain the consciousness and effect of historical erasure. Through an oxymoronic aesthetic that assembles a highly crafted verisimilitude alongside the condition of invisibility and brings atrocity into the orbit of the aesthetic, these portraits force us to question what stakes are involved in bringing the lives of the enslaved and violated back into regimes of representation.
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The elaboration of curli fimbriae by Escherichia coli is associated with the development of a lacy colony morphology when groan on colonisation factor antigen agar at 25 degrees C. Avian colisepticaemia E. coli isolates screened for curliation by this culture technique showed lacy and smooth colonial morphologies and the genetic basis of the non-curliated smooth colonial phenotype was analysed. Two smooth E, coli O78:K80 isolates possessed about 40 copies of the IS1 element within their respective genomes of which one copy insertionally inactivated the csgB gene, the nucleator gene for curli fibril formation. One of these two isolates also possessed a defective rpoS gene which is a known regulator of curli expression. In the day-old chick model, both smooth isolates were as invasive as a known virulent O78:K80 isolate as determined by extent of liver and spleen colonisation post oral inoculation but were less persistent in terms of caecal colonisation. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.
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Survival of enteric pathogens exposed to various environmental stresses depends upon a number of protective responses, some of which are associated with induction of virulence determinants. Flagella and fimbriae are putative virulence determinants of Salmonella spp, and ELISAs specific for the detection of flagella and SEF21, SEF14 and SEF17 fimbriae were used to assess the effect of temperature and pH upon their elaboration by isolates of Salmonella serotype Enteritidis in planktonic growth and on the surface of two-dimensional gradient agar plates, For three phage type 4 isolates of Enteritidis of comparative clinical provenance, similar phenotypes for the elaboration of these surface antigens were observed. SEF14 fimbriae were elaborated in planktonic growth at 37 degrees C, but not 20 degrees C, at pH 4.77 and above but not at pH 4.04; whereas on agar gradient plates SEF14 fimbriae were elaborated poorly but with best yields at pH 4.04, SEF17 fimbriae were elaborated in planktonic growth at 20 degrees C, but not at 37 degrees C, at pH 6.18 and above but not at pH 5.09 or below; whereas on agar gradient plates SEF17 fimbriae were elaborated well even at pH 4.65, SEF21 fimbriae were expressed very poorly under all conditions tested, Planktonic growth at 37 degrees C induced least flagella whereas growth at 20 degrees C, and particularly surface growth at lower pH values, induced a 'hyper-flagellate' phenotype, Single colonies allowed to form on gradient agar plates were shown to generate different colonial morphologies which were dependent on initial pH. These results demonstrate that the physicochemical environment is an important determinant of bacterial response, especially the induction of putative virulence factors.
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The drug quinine figured as an object of enforced consumption in British India between the late 1890s and the 1910s, when the corresponding diagnostic category malaria itself was redefined as a mosquito-borne fever disease. This article details an overlapping milieu in which quinine, mosquitoes and malaria emerged as intrinsic components of shared and symbiotic histories. It combines insights from new imperial histories, constructivism in the histories of medicine and literature about non-humans in science studies to examine the ways in which histories of insects, drugs, disease and empire interacted and shaped one another. Firstly, it locates the production of historical intimacies between quinine, malaria and mosquitoes within the exigencies and apparatuses of imperial rule. In so doing, it explores the intersections between the worlds of colonial governance, medical knowledge, vernacular markets and pharmaceutical business. Secondly, it outlines ways to narrate characteristics and enabling properties of non-humans (such as quinines and mosquitoes) while retaining a constructivist critique of scientism and empire. Thirdly, it shows how empire itself was reshaped and reinforced while occasioning the proliferation of categories and entities like malaria, quinine and mosquitoes.
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David Arnold who retired this year as the Professor of Asian and Global History at the University of Warwick remains one of the most prolific historians of colonial medicine and modern South Asia. A founding member of the subaltern studies collective, he is considered widely as a pioneer in the histories of colonial medicine, environment, penology, hunger and famines within South Asian studies and beyond. In this interview he recalls his formative inspirations, ideological motivations and reflects critically on his earlier works, explaining various shifts as well as map- ping the possible course of future work. He talks at length about his forthcoming works on everyday technology, food and monsoon Asia. Finally, he shares with us his desire of initiating work on an ambitious project about the twin themes of poison and poverty in South Asian his- tory, beginning with the Bengal famine in the late eighteenth century and ending with the Bhopal gas tragedy of the early 1980s. This conversation provides insights into the ways in which the field of medical history in modern South Asia has been shaped over the past three decades through interactions with broader discussions on agency, resistance, power, everydayness, subal- tern studies, global and spatial histories. It hints further at the newer directions which are being opened up by such persisting intellectual entanglements.
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This paper examines two late medieval abridgements of Gerald of Wales’ Expugnatio Hibernica, one in Hiberno-English and one in Irish. The manuscripts in which these adaptations survive all date from the late fifteenth century and appear to bear witness to a sudden and pronounced interest in Gerald’s text. Drawing on evidence from the extant manuscripts, this paper explores the readerships of, and the nature of their interest in, these adaptations. A key conclusion is that the Expugnatio, which gives prominence to Gerald's own relatives, the Fitzgeralds, was valued as a family history by the Fitzgerald Earls of Kildare and their allies. The Earls were at the height of their power in the period in which these manuscripts were produced. Examination of this neglected evidence of the adaptation and readership of the Expugnatio in late medieval Ireland suggests that, for some medieval readers at least, the primary identities Gerald’s text expressed were familial and local rather than colonial or national.
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This is a study of institutional change and continuity, comparing the trajectories followed by Mozambique and its formal colonial power Portugal in HRM, based on two surveys of firm level practices. The colonial power sought to extend the institutions of the metropole in the closing years of its rule, and despite all the adjustments and shocks that have accompanied Mozambique’s post-independence years, the country continues to retain institutional features and associated practices from the past. This suggests that there is a post-colonial impact on human resource management. The implications for HRM theory are that ambitious attempts at institutional substitution may have less dramatic effects than is commonly assumed. Indeed, we encountered remarkable similarities between the two countries in HRM practices, implying that features of supposedly fluid or less mature institutional frameworks (whether in Africa or the Mediterranean world) may be sustained for protracted periods of time, pressures to reform notwithstanding. This highlights the complexities of continuities which transcend formal rules; as post-colonial theories alert us, informal conventions and embedded discourse may result in the persistence of informal power and subordination, despite political and legal changes.