991 resultados para Reciprocity and Ritual. Homer and Tragedy in the Developing City-State
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Fil: Chazarreta, Daniela Evangelina. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.
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Fil: Chazarreta, Daniela Evangelina. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.
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Fil: Chazarreta, Daniela Evangelina. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.
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The neuroectodermal tissue close to the midbrain hindbrain boundary (MHB) is an important secondary organizer in the developing neural tube. This so-called isthmic organizer (IsO) regulates cellular survival, patterning and proliferation in the midbrain (Mb) and rhombomere 1 (R1) of the hindbrain. Signaling molecules of the IsO, such as fibroblast growth factor 8 (FGF8) and WNT1 are expressed in distinct bands of cells around the MHB. It has been previously shown that FGF-receptor 1 (FGFR1) is required for the normal development of this brain region in the mouse embryo. In the present study, we have compared the gene expression profiles of wild-type and Fgfr1 mutant embryos. We show that the loss of Fgfr1 results in the downregulation of several genes expressed close to the MHB and in the disappearance of gene expression gradients in the midbrain and R1. Our microarray screen identified several previously uncharacterized genes which may participate in the development of midbrain R1 region. Our results also show altered neurogenesis in the midbrain and R1 of the Fgfr1 mutants. Interestingly, the neuronal progenitors in midbrain and R1 show different responses to the loss of signaling through FGFR1. As Wnt1 expression at the MHB region requires the FGF signaling pathway, WNT target genes, including Drapc1, were also identified in our screen. The microarray data analysis also suggested that the cells next to the midbrain hindbrain boundary express distinct cell cycle regulators. We showed that the cells close to the border appeared to have unique features. These cells proliferate less rapidly than the surrounding cells. Unlike the cells further away from the boundary, these cells express Fgfr1 but not the other FGF receptors. The slowly proliferating boundary cells are necessary for development of the characteristic isthmic constriction. They may also contribute to compartmentalization of this brain region.
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Gamma-aminobutyric acid (GABA) is the most abundant inhibitory neurotransmitter in the vertebrate brain. In the midbrain, GABAergic neurons contribute to the regulation of locomotion, nociception, defensive behaviours, fear and anxiety, as well as sensing reward and addiction. Despite the clinical relevance of this group of neurons, the mechanisms regulating their development are largely unknown. In addition, their migration and connectivity patterns are poorly characterized. This study focuses on the molecular mechanisms specifying the GABAergic fate, and the developmental origins of midbrain GABAergic neurons. First, we have characterized the function of a zink-finger transcription factor Gata2. Using a tissue-specific mutagenesis in mouse midbrain and anteror hindbrain, we showed that Gata2 is a crucial determinant of the GABAergic fate in midbrain. In the absence of Gata2, no GABAergic neurons are produced from the otherwise competent midbrain neuroepithelium. Instead, the Gata2-mutant cells acquire a glutamatergic neuron phenotype. Ectopic expression of Gata2 was also sufficient to induce GABAergic in chicken midbrain. Second, we have analyzed the midbrain phenotype of mice mutant for a proneural gene Ascl1, and described the variable and region-dependent requirements for Ascl1 in the midbrain GABAergic neurogenesis. These studies also have implications on the origin of distinct anatomical and functional GABAergic subpopulations in midbrain. Third, we have identified unique developmental properties of GABAergic neurons that are associated with the midbrain dopaminergic nuclei, the substantia nigra pars reticulata (SNpr) and ventral tegmental area (VTA). Namely, the genetic regulation of GABAergic fate in these cells is distinct from the rest of midbrain. In accordance to this phenomenon, our detailed fate-mapping analyses indicated that the SNpr-VTA GABAergic neurons are generated outside midbrain, in the neuroepithelium of anterior hindbrain.
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Aniline pentamer and hexamer in the leucoemeraldine oxidation state were synthesized through a novel method. The method was accomplished by the reaction of parent aniline tetramer in the pernigraniline oxidation state with diphenylamine and N-phenyl-1,4-phenylenediamine in the leucoemeraldine oxidation state respectively. The oligomers in the leucoemeraldine oxidation state were characterized by IR, NMR, elemental analysis and MALDI-MS. Aniline pentamer and hexamer in the emeraldine oxidation state were synthesized by the oxidation of Ag2O in DMF. It was found that some fragmentation occurred when the pentamer and hexamer were oxidized by (NH4)(2)S2O8 and FeCl3. 6H(2)O. The pentamer and hexamer in the emeraldine oxidation state was studied by UV/Vis spectra. The relative intensity of exciton peak for pentaaniline showed a little increase compared with that of hexaaniline.
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Given the economic and social importance of agriculture in the early years of the Irish Free State, it is surprising that the development of organisations representing farmers has not received the attention it deserves from historians. While the issues of government agricultural policy and the land question have been extensively studied in the historiography, the autonomous response by farmers to agricultural policies and the detailed study of the farmers’ organisations has simply been ignored in spite of the existence of a range of relevant primary sources. Farmers’ organisations have only received cursory treatment in these studies; they have been presented as passive spectators, responding in a Pavlovian manner to outside events. The existing historiography has only studied farmers’ organisations during periods when they impinged on national politics, epecially during the War of Independence and the Economic War. Therefore chronological gaps exist which has led to much misinterpretation of farmers’ activities. This thesis will redress this imbalance by studying the formation and continuous development of farmers’ organisations within the twenty-six county area and the reaction of farmers to changing government agricultural policies, over the period 1919 to 1936. The period under review entailed many attempts by farmers to form representative organisations and encompassed differing policy regimes. The thesis will open in 1919, when the first national organisation representing farmers, the Irish Farmers’ Union, was formed. In 1922, the union established the Farmers’ Party. By the mid- 1920’s, a number of protectionist agricultural associations had been formed. While the Farmers’ Party was eventually absorbed by Cumann na nGaedheal, local associations of independent farmers occupied the resultant vacuum and contested the 1932 election. These organisations formed the nucleus of a new national organisation; the National Farmers’ and Ratepayers’ League. The agricultural crisis caused by both the Great Depression and the Economic War facilitated the expansion of the league. The league formed a political party, the Centre Party, to contest the 1933 election. While the Centre Party was absorbed by the newly-formed Fine Gael, activists from the former farmer organisations led the campaign against the payment of annuities and rates. Many of them continued this campaign after 1934, when the Fine Gael leadership opposed the violent resistance to the collection of annuities. New farmer organisations were formed to co-ordinate this campaign which continued until 1936, the closing point of the thesis.
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This paper explores the spatial conceptualisation of the themes of diaspora, displacement and desire in cinema, particularly in the work of Nuri Bilge Ceylan (Uzak) , Fatih Akin (Gegen Die Wand) and Michael Winterbottom (Code 46). All three directors explore the imagined cinematic city as a site of multiple (un)belongings and interrogate how notions of identity are displaced and disrupted by geopolitics, by the city and by cinema itself. Both Ceylan and Akin’s visions of Istanbul are haunted by Beyoglu, both as the site of Istanbul’s contemporary cultural regeneration and by unspoken histories repressed by the Republic’s offical rhetoric of Turkish identity. In contrast Akin and Winterbottom’s heterotopias of the hotel and the hospital provide possible metaphors for these dislocated global identities. This paper will engage with a series of questions. What is the (imagined) place created between the viewer and the screen, or is it a non-place? Do the identities/ memories created there produce a ‘third space’? This paper uses Winnicot, Soja and Bhabha to ask what that third space might be and its consequences for a contemporary global Turkish identity. If these films depict a (Freudian) screen memory of dislocated subjectivities then what is being suppressed and sutured?