This article reports key findings from a comparative survey of the role perceptions, epistemological orientations and ethical views of 1800 journalists from 18 countries. The results show that detachment, non-involvement, providing political information and monitoring the government are considered essential journalistic functions around the globe. Impartiality, the reliability and factualness of information, as well as adherence to universal ethical principles are also valued worldwide, though their perceived importance varies across countries. Various aspects of interventionism, objectivism and the importance of separating facts from opinion, on the other hand, seem to play out differently around the globe. Western journalists are generally less supportive of any active promotion of particular values, ideas and social change, and they adhere more to universal principles in their ethical decisions. Journalists from non-western contexts, on the other hand, tend to be more interventionist in their role perceptions and more flexible in their ethical views.

Based on interviews with 300 journalists in Chile, Brazil and Mexico, this article describes similarities and differences in their professional cultures. Two competing conceptual explanations are tested: the dominance of political structures, levels of press freedom and the size and concentration of media ownership vs the predominance of political cultures and political parallelism. Although the study provides some evidence in favour of the second scenario -overall in terms of the institutional roles supported by the journalists -neither of the two explanations can fully account for the differences between the countries. Meanwhile, the epistemological and ethical views of the journalists seem to be trapped in contesting terrains of ambiguity, where organizational, media routines and individual factors override country differences.

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Ionotropic glutamate receptors in cerebellar Bergmann glial cells are linked to transcriptional regulation and, by these means, are thought to play an important role in plasticity, learning and memory and in several neuropathologies. Within the CNS, the transcription factors of the POU family bind their target DNA sequences after a growth factordependent phosphorylation-dephosphorylation cascade. Exposure of cultured Bergmann glial cells to glutamate leads to a time-and dose-dependent increase in Oct-2 DNAbinding activity. The use of specific pharmacological tools established the involvement of Ca 2+ -permeable a-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors. Furthermore, the signaling cascade includes phosphatidyl inositol 3-kinase as well as protein kinase C activation. Interestingly, transcriptional as well as translational inhibitors abolish the glutamate effect, suggesting a transcriptional up-regulation of the oct-2 gene. These data demonstrate that Oct-2 expression is not restricted to neurons and further strengthen the notion that the glial glutamate receptors participate in the modulation of glutamatergic cerebellar neurotransmission.

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