939 resultados para Regime Shifts
Resumo:
O trabalho apresenta resultados de pesquisa acerca das políticas de educaçao no Brasil, do princípio regime de colaboraçao e da gestao da educaçao, apresentando, neste momento, aspectos da trajetória sociopolítica da elaboraçao ou adequaçao dos Planos Municipais de Educaçao (PMEs), deflagrada em 2013 pelo MEC/SASE, com as possibilidades de efetivaçao do regime de colaboraçao e da gestao democrática. Sua abordagem é qualitativa, de caráter teórico-empírico e exploratório, abarcando a documentaçao relativa aos PMEs dos Municípios. No Tocantins, até o início do ano de 2014, um georreferenciamento demonstra que dos 139 Municípios, apenas seis elaboraram seus PMEs. Neste contexto, predomina a visao de administraçao municipal restrita às suas instituiçoes escolares e ao tempo de sua gestao, sem relaçao ou articulaçao com metas nacionais comuns com vistas à materializaçao do Sistema Nacional de Educaçao. Deste processo, destaca-se o significativo movimento sociopolítico em torno do planejamento da educaçao no século XXI, enfrentado o desafio de definir o objetivo comum da educaçao brasileira. Entretanto, há ideias que merecem ser investigadas, como a sua concepçao de gestao e planejamento e as formas de colaboraçao estabelecidas
Resumo:
The late Cenozoic history of eolian sedimentation in the eastern Indian Ocean was developed from samples recovered during drilling of Sites 752, 754, and 756. Temporal changes in the mass accumulation rate of eolian material reflect major climatic shifts in the southern African source region. A significant drop in dust mass flux values occurs near the end of the lower Oligocene. Younger sediments are characterized by a gradual reduction in dust accumulation rates until the middle Miocene after which values remain consistently low throughout the late Cenozoic, although a slight increase in eolian accumulation rate occurs near 2.5 Ma. This pattern of dust mass flux appears related to the supply of dust-sized particles in the source region and represents a shift in the climatic regime of southern Africa to increasingly more arid conditions throughout the late Cenozoic.
Resumo:
O trabalho apresenta resultados de pesquisa acerca das políticas de educaçao no Brasil, do princípio regime de colaboraçao e da gestao da educaçao, apresentando, neste momento, aspectos da trajetória sociopolítica da elaboraçao ou adequaçao dos Planos Municipais de Educaçao (PMEs), deflagrada em 2013 pelo MEC/SASE, com as possibilidades de efetivaçao do regime de colaboraçao e da gestao democrática. Sua abordagem é qualitativa, de caráter teórico-empírico e exploratório, abarcando a documentaçao relativa aos PMEs dos Municípios. No Tocantins, até o início do ano de 2014, um georreferenciamento demonstra que dos 139 Municípios, apenas seis elaboraram seus PMEs. Neste contexto, predomina a visao de administraçao municipal restrita às suas instituiçoes escolares e ao tempo de sua gestao, sem relaçao ou articulaçao com metas nacionais comuns com vistas à materializaçao do Sistema Nacional de Educaçao. Deste processo, destaca-se o significativo movimento sociopolítico em torno do planejamento da educaçao no século XXI, enfrentado o desafio de definir o objetivo comum da educaçao brasileira. Entretanto, há ideias que merecem ser investigadas, como a sua concepçao de gestao e planejamento e as formas de colaboraçao estabelecidas
Resumo:
El ensayo apunta a pensar los cuadros realistas de Belmiro de Almeida a la luz de las teorías de Jacques Rancière, para quien el realismo literario del siglo XIX produce las condiciones de posibilidad para la fotografía y el cine. De este modo, se desplaza el foco de los análisis de la máquina (fotográfica o cinematográfica), más allá de reposicionarse el realismo como punto de articulación del régimen poético al régimen estético.
Resumo:
Vesicomyidae clams harbor sulfide-oxidizing endosymbionts and are typical members of cold seep communities associated with tectonic faults where active venting of fluids and gases takes place. We investigated the central biogeochemical processes that supported a vesicomyid clam colony as part of a locally restricted seep community in the Japan Trench at 5346 m water depth, one of the deepest seep settings studied to date. An integrated approach of biogeochemical and molecular ecological techniques was used combining in situ and ex situ measurements. During the cruise YK06-05 in 2006 with the RV Yokosuka to the Japan Trench, we investigated a clam colony inhabited by Abyssogena phaseoliformis (former known as Calyptogena phaseoliformis) and Isorropodon fossajaponicum (former known as Calyptogena fossajaponica). The targeted sampling and precise positioning of the in situ instruments were achieved with the manned research submersible Shinkai 6500 (JAMSTEC, Nankoku, Kochi, Japan). Sampling was first performed close to the rim of the JTC colony and then at the center. Immediately after sample recovery onboard, the sediment core was sub-sampled for ex situ rate measurements or preserved for later analyses. In sediment of the clam colony, low sulfate reduction (SR) rates (max. 128 nmol ml**-1 d**-1) were coupled to the anaerobic oxidation of methane (AOM). They were observed over a depth range of 15 cm, caused by active transport of sulfate due to bioturbation of the vesicomyid clams. A distinct separation between the seep and the surrounding seafloor was shown by steep horizontal geochemical gradients and pronounced microbial community shifts. The sediment below the clam colony was dominated by anaerobic methanotrophic archaea (ANME-2c) and sulfate-reducing Desulfobulbaceae (SEEP-SRB-3, SEEP-SRB-4). Aerobic methanotrophic bacteria were not detected in the sediment and the oxidation of sulfide seemed to be carried out chemolithoautotrophically by Sulfurovum species. Thus, major redox processes were mediated by distinct subgroups of seep-related microorganisms that might have been selected by this specific abyssal seep environment. Fluid flow and microbial activity was low but sufficient to support the clam community over decades and to build up high biomasses. Hence, the clams and their microbial communities adapted successfully to a low-energy regime and may represent widespread chemosynthetic communities in the Japan Trench.
Resumo:
Relict dune fields that are found as far south as 14° N in the modern-day African Sahel are testament to equatorward expansions of the Sahara desert during the Late Pleistocene. However, the discontinuous nature of dune records means that abrupt millennial-timescale climate events are not always resolved. High-resolution marine core studies have identified Heinrich stadials as the dustiest periods of the last glacial in West Africa although the spatial evolution of dust export on millennial timescales has so far not been investigated. We use the major-element composition of four high-resolution marine sediment cores to reconstruct the spatial extent of Saharan-dust versus river-sediment input to the continental margin from West Africa over the last 60 ka. This allows us to map the position of the sediment composition corresponding to the Sahara-Sahel boundary. Our records indicate that the Sahara-Sahel boundary reached its most southerly position (13° N) during Heinrich stadials and hence suggest that these were the periods when the sand dunes formed at 14° N on the continent. Heinrich stadials are associated with cold North Atlantic sea surface temperatures which appear to have triggered abrupt increases of aridity and wind strength in the Sahel. Our study illustrates the influence of the Atlantic meridional overturning circulation on the position of the Sahara-Sahel boundary and on global atmospheric dust loading.
Resumo:
The objective of this study was to determine shifts in the microbial community structure and potential function based on standard Integrated Ocean Drilling Program (IODP) storage procedures for sediment cores. Standard long-term storage protocols maintain sediment temperature at 4°C for mineralogy, geochemical, and/or geotechnical analysis whereas standard microbiological sampling immediately preserves sediments at -80°C. Storage at 4°C does not take into account populations may remain active over geologic time scales at temperatures similar to storage conditions. Identification of active populations within the stored core would suggest geochemical and geophysical conditions within the core change over time. To test this potential, the metabolically active fraction of the total microbial community was characterized from IODP Expedition 325 Great Barrier Reef sediment cores prior to and following a 3-month storage period. Total RNA was extracted from complementary 2, 20, and 40 m below sea floor sediment samples, reverse transcribed to complementary DNA and then sequenced using 454 FLX sequencing technology, yielding over 14,800 sequences from the six samples. Interestingly, 97.3% of the sequences detected were associated with lineages that changed in detection frequency during the storage period including key biogeochemically relevant lineages associated with nitrogen, iron, and sulfur cycling. These lineages have the potential to permanently alter the physical and chemical characteristics of the sediment promoting misleading conclusions about the in situ biogeochemical environment. In addition, the detection of new lineages after storage increases the potential for a wider range of viable lineages within the subsurface that may be underestimated during standard community characterizations.