48 resultados para Adiabatic potentials


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This study approaches the problem of poverty in the hinterlands of Northeast Brazil through the concept of structural violence, linking the environmental threats posed by climate change, especially those related to droughts, to the broader social struggles in the region. When discussions about potentials and rights are incorporated into the problematic of poverty, a deeper insight is obtained regarding the various factors behind the phenomenon. It is generally believed that climate change is affecting the already marginalized and poor more than those of higher social standing, and will increasingly do so in the future. The data for this study was collected during a three month field work in the states of Pernambuco and Paraíba in Northeast Brazil. The main methods used were semi-structured interviews and participant observation, including attending seminars concerning climate change on the field. The focus of the work is to compare both layman and expert perceptions on what climate change is about, and question the assumptions about its effects in the future, mainly that of increased numbers of ‘climate refugees’ or people forced to migrate due to changes in climate. The focus on droughts, as opposed to other manifestations of climate change, arises from the fact that droughts are not only phenomena that develop over a longer time span than floods or hurricanes, but is also due to the historical persistence of droughts in the region, and both the institutional and cultural linkages that have evolved around it. The instances of structural violence that are highlighted in this study; the drought industry, land use, and the social and power relations present in the region, including those between the civil society, the state and the private agribusiness sector, all work against a backdrop of symbolic and moral realms of value production, where relations between the different actors are being negotiated anew with the rise of the climate change discourse. The main theoretical framework of the study consists of Johan Galtung’s and Paul Farmer’s theory of structural violence, Ulrich Beck’s theory of the risk society, and James Scott’s theory of everyday peasant resistance.

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The Baltic Sea is one of the largest brackish water bodies in the world. Primary production in the Baltic Sea is limited by nitrogen (N) availability with the exception of river outlets and the northernmost phosphorus limited basin. The excess human induced N load from the drainage basin has caused severe eutrophication of the sea. The excess N loads can be mitigated by microbe mediated natural N removal processes that are found in the oxic-anoxic interfaces in sediments and water column redoxclines. Such interfaces allow the close coupling between the oxic nitrification process, and anoxic denitrification and anaerobic ammonium oxidation (anammox) processes that lead to the formation of molecular nitrogen gas. These processes are governed by various environmental parameters. The effects of these parameters on N processes were investigated in the northern Baltic Sea sediments. During summer months when the sediment organic content is at its highest, nitrification and denitrification reach their maximum rates. However, nitrification had no excess potential, which was probably because of high competition for molecular oxygen (O2) between heterotrophic and nitrification microbes. Subsequently, the limited nitrate (NO3-) availability inhibited denitrification. In fall, winter and spring, nitrification was limited by ammonium availability and denitrification limited by the availability of organic carbon and occasionally by NO3-. Anaerobic ammonium oxidation (anammox) was not an important N removal process in the northern Baltic Sea. Modeling studies suggest that when hypoxia expands in the Baltic Sea, N removal intensifies. However, the results of this study suggest the opposite because bottom water hypoxia (O2< 2 ml l-1) decreased the denitrification rates in sediments. Moreover, N was recycled by the dissimilatory nitrate reduction to ammonium (DNRA) process instead of being removed from the water ecosystem. High N removal potentials were found in the anoxic water column in the deep basins of the Baltic Proper. However, the N removal in the water column appeared to be limited by low substrate availability, because the water at the depths at which the substrate producing nitrification process occurred, rarely mix with the water at the depths at which N removal processes were found. Overall, the natural N removal capacity of the northern Baltic Sea decreased compared to values measured in mid 1990s and early 2000. The reason for this appears to be increasing hypoxia.

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The representation of morphologically complex words in the mental lexicon and their neurocognitive processing has been a vigorously debated topic in psycholinguistics and the cognitive neuroscience of language. This thesis investigates the effect of stimulus modality on morphological processing, the spatiotemporal dynamics of the neural processing of inflected (e.g., work+ed ) and derived (e.g., work+er ) words and their interaction, using the Finnish language. Overall, the results suggest that the constituent morphemes of isolated written and spoken inflected words are accessed separately, whereas spoken derived words activate both their full form and the constituent morphemes. The processing of both spoken and written inflected words elicited larger N400 responses than monomorphemic words (Study I), whereas the responses to spoken derived words did not differ from those to monomorphemic words (Study IV). Spoken inflected words elicited a larger left-lateralized negativity and greater source strengths in the left temporal cortices than derived words (Study IV). Thus, the results suggest different cortical processing for derived and inflected words. Moreover, the neural mechanisms underlying inflection and derivation seem to be not only different, but also independent as indexed by the linear summation of the responses to derived and inflected stimuli in a combined (derivation+inflection) condition (Study III). Furthermore, the processing of meaningless, spoken derived pseudowords was more difficult than for existing derived words, indexed by a larger N400-type effect for the pseudowords. However, no differences were observed between meaningful derived pseudowords and existing derived words (Study II). The results of Study II suggest that semantic compatibility between morphemes seems to have a crucial role in a successful morphological analysis. As a methodological note, time-locking the auditory event-related potentials/fields (ERP/ERF) to the suffix onset revealed the processes related to morphological analysis more precisely (Studies II and IV), which also enables comparison of the neural processes in different modalities (Study I).