Silent interrupted aortic arch in an elderly patient

Patients with complete interruption of the aortic arch (IAA) very rarely reach late adulthood without having undergone surgical intervention. Only a few cases of IAA in adults have been reported in the medical literature. In this case report, we present a late diagnosis of interrupted aortic arch in a 68 year-old male. Our patient was relatively asymptomatic until he presented with fatigue after walking quickly. A guidewire could not be passed to the aortic arch via the femoral approach; descending thoracic aortography revealed complete occlusion of the descending thoracic aorta. Cardiac catheterization via the right brachial artery confirmed the diagnosis of a complete interruption of the aortic arch distal to the left subclavian artery and showed distinct collateral circulation predominantly via the internal mammary arteries. Also, magnetic resonance angiography showed cuttings that reveal the interruption in the aortic arch and the prominent collateral vessels to the descending aorta. This case report was also interesting in that pressure measurements at a proximal point of the interrupted aortic arch were not hypertensive. Using both catheters, placed proximally and distally to the point of the interruption, by simultaneous pressure measurement, it was measured as 120/75 mm Hg at the proximal point, 60/40 mm Hg at the distal point. (Cardiol J 2011; 18, 6: 695–697

Alpha-induced reactions for the astrophysical p-process: the case of 151Eu

The cross sections of 151Eu(alpha,gamma)155Tb and 151Eu(alpha,n)154Tb reactions have been measured with the activation method. Some aspects of the measurement are presented here to illustrate the requirements of experimental techniques needed to obtain nuclear data for the astrophysical p-process nucleosynthesis. Preliminary cross section results are also presented and compared with the predictions of statistical model calculations.Comment: Accepted for publication in Journal of Physics Conference Series, proceeding of the Nuclear Physics in Astrophysics IV. conferenc

How phyllosilicate mineral structure affects fault strength in Mg-rich fault systems

The clay mineralogy of fault gouges has important implications for the frictional properties of faults, often identified as a major factor contributing to profound fault weakness. This work compares the frictional strength of a group of Mg‐rich minerals common in the Mg‐Al‐Si‐O compositional space (talc, saponite, sepiolite, and palygorskite) by conducting triaxial frictional tests with water or argon as pore fluid. The studied minerals are chemically similar but differ in their crystallographic structure. Results show that fibrous Mg‐rich phyllosilicates are stronger than their planar equivalents. Frictional strength in this group of minerals is highly influenced by strength of the atomic bonds, continuity of water layers within the crystals, and interactions of mineral surfaces with water molecules, all of which are dictated by crystal structure. The formation and stability of the minerals studied are mainly controlled by small changes in pore fluid chemistry, which can lead to significant differences in fault strength

Towards a modular language curriculum for using tasks

Task-based language teaching (TBLT) and task-supported language teaching (TSLT) are often seen as incompatible as they draw on different theories of language learning and language teaching. The position adopted in this article, however, is that both approaches are needed especially in instructional contexts where ‘pure’ task-based teaching may be problematic for various reasons. The article makes a case for a modular curriculum consisting of separate (i.e. non-integrated) task-based and structure-based components. Different curriculum models are considered in the light of what is known about how a second language is learned. The model that is proposed assumes the importance of developing fluency first. It consists of a primary task-based module implemented with focus-on-form (Long, 1991) and, once a basic fluency has been achieved, supported by a secondary structural module to provide for explicit accuracy-oriented work to counteract learned selective attention (N. Ellis, 2006): one of the main sources of persistent error. The article also addresses the content and grading of the task-based and structural modules. It considers the factors that need to be considered in the vertical and horizontal grading of tasks but also points out that, for the time being, syllabus designers will have to draw on their experience and intuition as much as on research to make decisions about how to sequence tasks. An argument is presented for treating the structural component as a checklist rather than as a syllabus so as to allow teachers to address selectively those features that are found to be problematic for their students when they perform tasks