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Period Mechanism of Semilunar Eclosion Rhythm of the Marine Midge Pontomyia oceanaChang, Yin-hao 07 August 2006 (has links)
We studied the eclosion rhythm of the marine midge Pontomyia oceana in southern Taiwan. The lunar/semilunr rhythm is known to be endogenous since it persists under continous light or dark conditions. In this study, we discovered that the period of the eclosion rhythm is about 15 days, although the midges have to spend an additional 15 days in the beginning of their lives before entering the eclosion rhythm. The period of the semilunrar eclosion rhythm is controlled by counting cycles of endogenous circadian rhythms which in term was entrainable by external light-dark (LD) cycles. We demonstrated this by modifying the period of LD cycles in different parts of their life histories with or without the entraining factor and then observing the ecolsion times in the laboratory. Night light can entrain the semilunar eclosion rhythm; we discovered that the cue and the eclosion are in the same phase of the semilunar rhythm but with a full cycle of shift. Temperature compensation in period control is demonstrated in this species. Q10 values close to 1 is found between 24 to 30¢XC in the laboratory.
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The Effect of Temperature on Synchronized Eclosion and the Study of Eclosion Rhythm of the Marine Midge Pontomyia oceanaLee, Pin-Hsien 15 June 2000 (has links)
Abstract
The effects of temperature on daily eclosion time and monthly eclosion days of the marine midge Pontomyia oceana were investigated. We changed temperature at different times on the eclosion day. The results show that P. oceana has started related metabolic processes at sunrise which lead to eclosion after sunset. Daily temperature cycles do not have concentrating effect on daily eclosion time. Two peaks of eclosion dates occurred from the same batch of fertilized eggs in the laboratory without cyclic environmental factors. High culturing temperature results in short interval (duration) between fertilization and eclosion, whereas more days are required at low temperature. The culturing temperature has a significant influence upon the numbers of P. oceana occurring in different eclosion peaks. High first/second peak ratio occurred at high temperatures whereas relatively more eclosed at the second peak at low temperature. The eclosion dates of offspring are not related to their parents with regard to the 2 peaks. There was an corresponding shift in eclosion days in eggs fertilized 2 days apart. It suggested that circasemilunar eclosion times were not caused by cues in the laboratory.
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Mechanism of Circasemilunar Eclosion rhythm of the Marine Midge Pontomyia oceanaLee, Yi-jen 31 July 2002 (has links)
The mechanism of semilunar emergence rhythm of the marine midge, Pontomyia oceana, was investigated. We used night light (1 lux) to entrain the emergence of the midge. Night light of 4 nights or more can effectively synchronize the semilunar emergence. Moreover, the night light has to be given about 10 days after fertilization to be effective. A batch of fertilized eggs of the marine midge emerge in two semilunar cycles, a second round of night-light treatment is necessary to synchronize the second peak of emergence. We also investigate whether the semilunar rhythm is dependent on the daily rhythm of the midge. Using different day length, from 20 to 28 hours per day, with equal light and dark periods, we want to know if the midges are counting numbers of light-dark cycles, or are independent of light-dark cycles, in determining their semilunar emergence. The results were intermediate between the two hypotheses. We suggest that the midge was not affected by light-dark cycle for the first 14 days of their life, afterward they count 15 light-dark cycles before emergence. This also explains how the second emergence peak occurs about 45 days after fertilization.
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[en] OVERSEAS REPUBLICS: IDEAL SOCIETIES IN EARLY MODERN ENGLAND / [pt] REPÚBLICAS DO ALÉM-MAR: SOCIEDADES IDEAIS NA INGLATERRA DA PRIMEIRA MODERNIDADEVICTOR DE SA MACHADO 22 June 2020 (has links)
[pt] O presente trabalho tem como proposta discutir The Commonwealth of Oceana (1656), de James Harrington, situando-a no âmbito de uma literatura política dedicada à constituição de sociedades ideais na Inglaterra da Primeira Modernidade. Para tanto, abordaremos os conceitos de sociedade ideal e de utopia a partir de uma leitura de Utopia (1516) de Thomas More. Tanto Utopia, quanto Oceana são repúblicas ficcionais que, inspiradas na Antiguidade Clássica, apresentam uma sociedade livre, com ampla participação popular e fundadas em leis virtuosas. No entanto, esses textos são separados por mais de um século e também escritos sob diferentes contextos políticos. Ainda assim, destacam-se as sagazes imaginações políticas que os atravessam. Assim, esta dissertação analisa as diferenças e semelhanças tanto nas formas quanto nas funções dessas obras, ressaltando as transformações que o gênero utópico sofreu no decorrer dos anos e como isso transformou a sua interpretação. O debate em torno das sociedades ideais, especialmente do conceito de utopia, é substancial para a pesquisa, uma vez que se considera possível interpretar a obra de Harrington como utópica. / [en] The present work proposes to discuss The Commonwealth of Oceana (1656) by James Harrington, placing the work within the framework of a political literature dedicated to the constitution of ideal societies in Early Modernity England. It treats the concepts of ideal society and utopia while engaging in a reading of Thomas More s Utopia (1516). Both Utopia and Oceana are fictional republics, which, inspired by Classical Antiquity, present a free society with broad popular participation and founded on virtuous laws. These texts are separated by a time gap of more than a century and also written under different political contexts. Nonetheless, the shrewd political imaginations that made them stand out. Thus, this dissertation analyzes the differences and similarities both in the forms and the functions of these works, highlighting the transformations that the utopian genre has undergone over the years and how this has transformed its interpretation. The debate about ideal societies, especially the concept of utopia, is substantial for this research since it deems possible to interpret Harrington s work as utopia.
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Through the vale of darkness : history in South Malakula, Vanuatude Lannoy, Jean January 2004 (has links)
The thesis is a multi-vocal and localized history of the destruction of ancient Malakulan society through depopulation, migration and conversion, of the salvation of some people who gathered around Christian communities, and of the relationship of these people and their descendants to the places they have left and to the communities in which they now live. The thesis brings a historical perspective to Vanuatu anthropology. Compared to earlier work in anthropological history in the Pacific by Sahlins, Dening and Bronwen Douglas, the main innovation in method is that all historical statements are set in their context, emphasizing the multiplicity of view points and revealing the significance of even minor variations which refer to important local issues, from land disputes to conversion to Christianity. Innovative use is made of funerary inscriptions, local maps and court archives, reflecting local forms of historical literacy. The research is part of a growing interest in Christianity in Oceania, after a long neglect by anthropologists. This is the first historical anthropology of Vanuatu and perhaps Melanesia to consider the long-term social impact of the dramatic depopulation that accompanied the colonial expansion of Europeans. The abandonment of the interior of the island of Malakula and the weakening of traditional links with other islands have reduced the social space of Malakula to the original zone of contact with Europeans, the coastal areas and nearby small islands. I argue that Christianity allowed the people of Malakula to create a new form of sociality in response to these events. The new society has its own time and space organized around the nuclear family meal and Sunday service, which were the two cornerstones of the conversion process, symbolizing the abandonment of former ritual activities and of the segregation of cooking fires according to ritual status. This process of cultural adaptation continues with the appropriation by villagers of the historical perspective of official courts favouring material evidence and legalistic principles in land disputes. Earlier research on Vanuatu was dominated by the themes of 'kastom', a discourse on tradition opposed to Western ways, and of the rootedness of people in place. This double emphasis is linked to the fact that most fieldwork in the country was done in the 1970s before a fifteen years ban on foreign research after Independence in 1980. In the context of the struggle for Independence and the restitution of alienated land, Vanuatu people needed to emphasize indigenous values and attachment to land. Today, priorities on the ground have changed and new types of discourses have come to the fore emphasizing conversion to Christianity and adopting new concepts reflecting a shift in preoccupation from recovering colonial land to the relation between indigenous Christian migrants and original owners.
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Hopeful Politics: The Interregnum UtopiasHayduk, Ulf Christoph January 2005 (has links)
The period of English history between the second Civil War and the Restoration opened up seemingly unlimited possibilities for shaping the country�s future. The period likewise witnessed an unprecedented surge of political imagination, a development which is particularly visible in Interregnum utopianism. More than ever before, utopianism orientates itself to a hopeful and expectant reality. It is no longer fictional or contemplative. Its ambitions and fulfilment are political; there is a drive towards active political participation. Utopianism reshapes its former boundaries and reinvents itself as reality utopianism. Considering this new reality-orientated identity, the utopias of the 1650s are especially useful in providing an insight into the political imagination of this period. This thesis studies three reality utopias of the 1650s: Winstanley�s The Law of Freedom, Harrington�s Oceana and Hobbes�s Leviathan. Each work represents a uniquely different utopian vision: Winstanley imagines an agrarian communism, Harrington revives classical republicanism, and Hobbes stresses absolute sovereignty. These three different utopian visions not only illustrate the range of the political imagination; they provide an opportunity to examine different ways to deal with the existing political and social concerns of the Interregnum and different perspectives for ideal solutions. Interregnum utopianism is shaped by the expectations and violence of the English Revolution and accordingly it is characterised by the heightened hopes and fears of its time. Despite substantial differences in the three utopias, the elemental hopes and fears expressed in these works remain similar. The hope for change and a better future is negotiated textually with a fear of anarchy and violence. In the end a compromise between opportunity and security has to be found. It is this compromise that shapes the face of Interregnum utopianism and reflects a major aspect of the post-revolutionary political imagination in England.
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Adaptation Mechanism of Eclosion Date Dimorphism in the Marine Midge Pontomyia oceana (Diptera¡GChironomidae)Leu, Yi-Jye 16 July 2001 (has links)
Two peaks of eclosion dates, about 15 days apart, occur in the same batch of fertilized eggs in the marine midge, Pontomyia oceana. Two hypotheses, the variable adaptive peaks and the bet-hedging hypotheses, were proposed as the ultimate factor of the polymorphic phenomenon. They were tested by experiments controlling feeding amount and photoperiod, as well as selective breeding experiments. The offspring eclosing in the two peaks do not differ in fecundities, egg diameters, thorax and head lengths of males; this is not compatible with the variable adaptive peaks hypothesis. Both peaks exist under various feeding and photoperiods, although peak ratios differed in the former. The results in the first peak lineage did not support there is genetic component in peak ratio determination. The experiments in the second peak lineage had much lower success rates, although the results seemed to suggest a genetic component. The results in a more extreme selection experiment did not support that there is genetic component either. The present results are more compatible with the bet-hedging hypothesis. Wind velocity may be a factor hard to predict by the midges, and it may cause reproductive failure of them. Whereas high emergence synchronization, a prominent feature of the marine midge, may have advantages in many aspects, it also concentrates the risk of total reproductive failure. Spreading offspring to more than one suitable eclosion peak, the midge may have sacrificed short-term reproductive rate for long-term fitness.
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Hopeful Politics: The Interregnum UtopiasHayduk, Ulf Christoph January 2005 (has links)
The period of English history between the second Civil War and the Restoration opened up seemingly unlimited possibilities for shaping the country�s future. The period likewise witnessed an unprecedented surge of political imagination, a development which is particularly visible in Interregnum utopianism. More than ever before, utopianism orientates itself to a hopeful and expectant reality. It is no longer fictional or contemplative. Its ambitions and fulfilment are political; there is a drive towards active political participation. Utopianism reshapes its former boundaries and reinvents itself as reality utopianism. Considering this new reality-orientated identity, the utopias of the 1650s are especially useful in providing an insight into the political imagination of this period. This thesis studies three reality utopias of the 1650s: Winstanley�s The Law of Freedom, Harrington�s Oceana and Hobbes�s Leviathan. Each work represents a uniquely different utopian vision: Winstanley imagines an agrarian communism, Harrington revives classical republicanism, and Hobbes stresses absolute sovereignty. These three different utopian visions not only illustrate the range of the political imagination; they provide an opportunity to examine different ways to deal with the existing political and social concerns of the Interregnum and different perspectives for ideal solutions. Interregnum utopianism is shaped by the expectations and violence of the English Revolution and accordingly it is characterised by the heightened hopes and fears of its time. Despite substantial differences in the three utopias, the elemental hopes and fears expressed in these works remain similar. The hope for change and a better future is negotiated textually with a fear of anarchy and violence. In the end a compromise between opportunity and security has to be found. It is this compromise that shapes the face of Interregnum utopianism and reflects a major aspect of the post-revolutionary political imagination in England.
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