Late Pleistocene history of turbidite sedimentation in a submarine canyon off the northern Great Barrier Reef, Australia

Cores from slopes east of the Great Barrier Reef (GBR) challenge traditional models for sedimentation on tropical mixed siliciclastic-carbonate margins. However, satisfactory explanations of sediment accumulation on this archetypal margin that include both hemipelagic and turbidite sedimentation remain elusive, as submarine canyons and their role in delivering coarse-grained turbidite deposits, are poorly understood. Towards addressing this problem we investigated the shelf and canyon system bordering the northern Ribbon Reefs and reconstructed the history of turbidite deposition since the Late Pleistocene. High-resolution bathymetric and seismic data show a large paleo-channel system that crosses the shelf before connecting with the canyons via the inter-reef passages between the Ribbon Reefs. High-resolution bathymetry of the canyon axis reveals a complex and active system of channels, sand waves, and local submarine landslides. Multi-proxy examination of three cores from down the axis of the canyon system reveals 18 turbidites and debrites, interlayered with hemipelagic muds, that are derived from a mix of shallow and deep sources. Twenty radiocarbon ages indicate that siliciclastic-dominated and mixed turbidites only occur prior to 31 ka during Marine Isotope Stage (MIS) 3, while carbonate-dominated turbidites are well established by 11 ka in MIS1 until as recently as 1.2 ka. The apparent lack of siliciclastic-dominated turbidites and presence of only a few carbonate-dominated turbidites during the MIS2 lowstand are not consistent with generic models of margin sedimentation but might also reflect a gap in the turbidite record. These data suggest that turbidite sedimentation in the Ribbon Reef canyons, probably reflects the complex relationship between the prolonged period (> 25 ka) of MIS3 millennial sea level changes and local factors such as the shelf, inter-reef passage depth, canyon morphology and different sediment sources. On this basis we predict that the spatial and temporal patterns of turbidite sedimentation could vary considerably along the length of the GBR margin.

Ultra compact inline E-plane waveguide extracted pole bandpass filters

This letter presents an ultra compact extracted pole E-plane filter. The proposed structure can achieve up to 65% size reduction in comparison with a standard extracted pole filter designed at 9.5 GHz centre frequency with a 3% fractional bandwidth. The filter has been fabricated and tested using E-plane waveguide technology. Measurements on a fabricated filter confirm the accuracy of the design method.

La recherche de « sexiness » chez les adeptes de pole-fitness : une étude de terrain montréalais

Cette étude explore la transformation des critères normatifs qui donnent accès au statut de femmes respectables à travers le concept de nouveau sujet féminin discuté par Radner (1999), Gill (2008; 2012) et McRobbie (1993; 2009) où l’idée de recherche active de « sexiness » chez les femmes à l’époque contemporaine est centrale. Le post-féminisme, une formation discursive qui émerge dans les années 1980, est identifié comme étant à l’origine de ces transformations. Cette position identitaire permettrait aux femmes de résister aux stigmates attachés à celles qui se posent comme sujet sexuel actif plutôt que comme objet sexuel passif et conduirait ainsi à l’« empowerment » sexuel. Or, cette vision du nouveau sujet féminin est contestée puisqu’elle ne représenterait qu’une seule possibilité d’émancipation à travers le corps et deviendrait par sa force normative un nouveau régime disciplinaire du genre féminin. L’interprétation valable à donner au nouveau sujet féminin représente un débat polarisé dans les milieux féministes et ce mémoire cherche à y apporter des éléments de discussion par l’étude des motivations des femmes à s’inscrire à des cours de pole-fitness et des significations qu’elles donnent à leur pratique. Ce mémoire apporte des éléments à la compréhension de l’impact de cette recherche de « sexiness » sur la subjectivité des femmes à travers les concepts de pratiques disciplinaires et stratégies de résistance.

The European Union in the Arctic: A Pole Position? Bruges Regional Integration & Global Governance Papers 4/2012, December 2012

With temperatures in the Arctic rising at twice the pace of anywhere else in the world, the European Union (EU) decided in 2008 to begin formulating an overall Arctic policy tackling maritime, environmental, energy and transport challenges. This attempt to draft a comprehensive policy on a topic that the EU had rarely touched upon unavoidably ran up against other existing strategies from Arctic and non-Arctic states. Against this background, this paper examines whether the EU’s current Arctic policy is conducive to framing a strategy that is both correctly targeted and flexible enough to represent Europe’s interests. It shows that the EU’s approach can serve as an effective foreign policy tool to establish the Union’s legitimacy as an Arctic player. However, the EU’s Arctic policy is still underestimating its potential to find common grounds with the strategic partners Russia and China. A properly targeted Arctic policy could help influence Russia over the EU’s interests in the Northern Sea Route and strengthen cooperation with China in an endeavour to gain recognition as relevant Arctic players.

Building cluster and shading in urban canyon for hot dry climate - Part 1: Air and surface temperature measurements

Under low latitude conditions, minimization of solar radiation within the urban environment may often be a desirable criterion in urban design. The dominance of the direct component of the global solar irradiance under clear high sun conditions requires that the street solar access must be small. It is well known that the size and proportion of open spaces has a great influence on the urban microclimate This paper is directed towards finding the interaction between urban canyon geometry and incident solar radiation. The effect of building height and street width on the shading of the street surfaces and ground for different orientations have been examined and evaluated. It is aimed to explore the extent to which these parameters affect the temperature in the street. This work is based on air and surface temperature measurements taken in different urban street canyons in EL-Oued City (hot and and climate), Algeria. In general, the results show that there are less air temperature variations compared to the surface temperature which really depends on the street geometry and sky view factor. In other words, there is a big correlation between the street geometry, sky view factor and surface temperatures.

Building cluster and shading in urban canyon for hot dry climate Part 2: Shading simulations

Under low latitude conditions, minimisation of solar irradiance within the urban environment may often be an important criterion in urban design. This can be achieved when the obstruction angle is large (high H/W ratio, H = height, W = width). Solar access to streets can always be decreased by increasing H/W to larger values. It is shown in this paper that the street canyon orientation (and not only the H/W ratio) has a considerable effect on solar shading and urban microclimate. The paper demonstrates through a series of shading simulation and temperature measurements that a number of useful relationships can be developed between the geometry and the microclimate of urban street canyons. These relationships are potentially helpful to assist in the formulation of urban design guidelines governing street dimensions and orientations for use by urban designers.