407 research outputs found

    The planform of epeirogeny: vertical motions of Australia during the Cretaceous

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    Estimates of dynamic motion of Australia since the end of the Jurassic have been made by modeling marine flooding and comparing it with palaeogeographical reconstructions of marine inundation. First, sediment isopachs were back stripped from present-day topography. Dynamic motion was determined by the displacement needed to approximate observed flooding when allowance is made for changes in eustatic sea-level. The reconstructed inundation patterns suggest that during the Cretaceous, Australia remained a relatively stable platform, and flooding in the eastern interior during the Early Cretaceous was primarily the result of the regional tectonic motion. Vertical motion during the Cretaceous was much smaller than the movement since the end of the Cretaceous. Subsidence and marine flooding in the Eromanga and Surat Basins, and the subsequent 500 m of uplift of the eastern portion of the basin, may have been driven by changes in plate dynamics during the Mesozoic. Convergence along the north-east edge of Australia between 200 and 100 Ma coincides with platform sedimentation and subsidence within the Eromanga and Surat Basins. A major shift in the position of subduction at 140 Ma was coeval with the marine incursion into the Eromanga. When subduction ended at 95 Ma, marine inundation of the Eromanga also ended. Subsidence and uplift of the eastern interior is consistent with dynamic models of subduction in which subsidence is generated when the dip angle of the slab decreases and uplift is generated when subduction terminates (i.e. the dynamic load vanishes). Since the end of the Cretaceous, Australia has uniformly subsided by about 250 m with little apparent tilting. This vertical subsidence may have resulted from the northward migration of the continent from a dynamic topography high and geoid low toward lower dynamic topography and a higher geoid.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71983/1/j.1365-2117.1994.tb00076.x.pd

    From Labyrinth to Piano Key Weirs – A historical review

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    Free crest spillways are hydraulically efficient and safe in operation. Since their discharge capacity is directly proportional to the crest length several types have been developed with the purpose to increase the length of the latter. Among these types traditional labyrinth weir spillways have been studied and used for a long time. Their hydraulic performance and the effect of the involved geometrical parameters are well known. Nevertheless, their design still has to be based on experimentally derived and generalized performance curves. The recently introduced Piano Key weirs present clear advantages regarding hydraulic performance and construction costs compared to classical labyrinth weirs. Especially its small footprint makes the PK weir an efficient and cost effective solution for the increase of the flood releasing capacity at existing concrete gravity dams. Until today only preliminary design procedures are available which cannot yet be generalized. The still ongoing research on this complex hydraulic structure is a challenge for many scientists all over the world. Despite of this, several prototypes have been installed successfully over the last years on existing dams which enhance efficiently the flood release capacity

    The pyramidalis-anterior pubic ligament-adductor longus complex (PLAC) and its role with adductor injuries: a new anatomical concept.

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    PURPOSE: Adductor longus injuries are complex. The conflict between views in the recent literature and various nineteenth-century anatomy books regarding symphyseal and perisymphyseal anatomy can lead to difficulties in MRI interpretation and treatment decisions. The aim of the study is to systematically investigate the pyramidalis muscle and its anatomical connections with adductor longus and rectus abdominis, to elucidate injury patterns occurring with adductor avulsions. METHODS: A layered dissection of the soft tissues of the anterior symphyseal area was performed on seven fresh-frozen male cadavers. The dimensions of the pyramidalis muscle were measured and anatomical connections with adductor longus, rectus abdominis and aponeuroses examined. RESULTS: The pyramidalis is the only abdominal muscle anterior to the pubic bone and was found bilaterally in all specimens. It arises from the pubic crest and anterior pubic ligament and attaches to the linea alba on the medial border. The proximal adductor longus attaches to the pubic crest and anterior pubic ligament. The anterior pubic ligament is also a fascial anchor point connecting the lower anterior abdominal aponeurosis and fascia lata. The rectus abdominis, however, is not attached to the adductor longus; its lateral tendon attaches to the cranial border of the pubis; and its slender internal tendon attaches inferiorly to the symphysis with fascia lata and gracilis. CONCLUSION: The study demonstrates a strong direct connection between the pyramidalis muscle and adductor longus tendon via the anterior pubic ligament, and it introduces the new anatomical concept of the pyramidalis-anterior pubic ligament-adductor longus complex (PLAC). Knowledge of these anatomical relationships should be employed to aid in image interpretation and treatment planning with proximal adductor avulsions. In particular, MRI imaging should be employed for all proximal adductor longus avulsions to assess the integrity of the PLAC

    The photochemistry of N-p-toluenesulfonyl peptides: the peptide bond as an electron donor

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    The scope of photobiological processes that involve absorbers within a protein matrix may be limited by the vulnerability of the peptide group to attack by highly reactive redox centers consequent upon electronic excitation. We have explored the nature of this vulnerability by undertaking comprehensive product analyses of aqueous photolysates of 12 N-p-toluene-sulfonyl peptides with systematically selected structures. The results indicate that degradation includes a major pathway that is initiated by intramolecular electron transfer in which the peptide bond serves as electron donor, and the data support the likelihood of a relay process in dipeptide derivatives

    European Competition Policy in International Markets

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    International audienceChanges in the institutional, technological and economic environment raise new challenges to the European competition policy. In this context, it is timely for European authorities to appraise the external dimension of the European competition policy as well as its articulation with current internal reforms. Globalisation can increase the costs of monitoring and seriously reduce the ability of European authorities to tackle cross-border anti-competitive conducts. In addition, conflicts are exacerbated by industrial policy motivations. As it is unlikely that the sole application of the territoriality and extraterritoriality principles to competition rules could yield an optimal international competition system, globalisation calls for higher levels and types of cooperation. Given that bilateral cooperation and especially the implementation of comity principles could be of no value when laws or interests are sources of international conflicts, three main paths could be therefore encouraged: The continuous harmonization of rules through the joint action of OECD and ICN; the higher cooperation in the confidential information exchange; the establishment of global anti-trust institutions. Although WTO is legitimate in judging questions related market access and entry barriers, it is less equipped to assess international hard core cartels or M&A reviews. As a substitute for WTO, a multilevel system, like the EU system, could be promoted. For political and pragmatic reasons, it could be composed in a first step of a hard core of countries like the EU, Japan and the U.S. It could be associated with the creation of an international Court of Justice for competition. In addition to these external reforms, some internal reforms could be required. Competition authorities have to develop further competition advocacy to give a higher priority to competition issues in other EU policies and national regulation. A parallel and complementary reform could consist in making the European competition agency independent from State Members' interference
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