Effects of periodic unsteadiness of a rocket engine plume on the plume-induced separation shock wave

A wind tunnel investigation was conducted to study the flow field in which separation is caused by an expanding plume, with emphasis on effects associated with periodic unsteadiness in the plume. The separation shock was photographed with high speed motion pictures, from which mean shock position and excursion data are reported. Pressure fluctuations were measured beneath the separation shock and statistics of the results are reported. A response of the separation shock to plume periodic unsteadiness was identified, and the magnitude of a corresponding transfer function was defined and is reported

Optimal psycholinguistic environments for distance foreign langauge learning

Rational choices among the numerous technological options available for foreign language teaching need to be based, in part, on psycholinguistic considerations. Which technological advances help create an optimal psycholinguistic environment for language learning, and which may be innovative but relatively unhelpful? One potential source of guidance is offered by the ten methodological principles of Task-Based Language Teaching (Long, 1985, and elsewhere), each realizable by a variety of pedagogic procedures. Interest in TBLT derives from several sources, including its responsiveness to learners’ precisely specified communicative needs, the potential it offers for developing functional language proficiency without sacrificing grammatical accuracy, and its attempt to harmonize the way languages are taught with what SLA research has revealed about how they are learned. TBLT’s ten methodological principles are briefly defined and motivated, and illustrations provided of how the principles can inform choices among technological options in the particular case of distance education for the less commonly taught languages

A Golgi and tonoplast localized S-acyl transferase is involved in cell expansion, cell division, vascular patterning and fertility in Arabidopsis

S‐acylation of eukaryotic proteins is the reversible attachment of palmitic or stearic acid to cysteine residues, catalysed by protein S‐acyl transferases that share an Asp‐His‐His‐Cys (DHHC) motif. Previous evidence suggests that in Arabidopsis S‐acylation is involved in the control of cell size, polarity and the growth of pollen tubes and root hairs. Using a combination of yeast genetics, biochemistry, cell biology and loss of function genetics the roles of a member of the protein S‐acyl transferase PAT family, AtPAT10 (At3g51390), have been explored. In keeping with its role as a PAT, AtPAT10 auto‐S‐acylates, and partially complements the yeast akr1 PAT mutant, and this requires Cys192 of the DHHC motif. In Arabidopsis AtPAT10 is localized in the Golgi stack, trans‐Golgi network/early endosome and tonoplast. Loss‐of‐function mutants have a pleiotropic phenotype involving cell expansion and division, vascular patterning, and fertility that is rescued by wild‐type AtPAT10 but not by catalytically inactive AtPAT10C192A. This supports the hypothesis that AtPAT10 is functionally independent of the other Arabidopsis PATs. Our findings demonstrate a growing importance of protein S‐acylation in plants, and reveal a Golgi and tonoplast located S‐acylation mechanism that affects a range of events during growth and development in Arabidopsis

Integrating e-learning into postgraduate radiotherapy and oncology education: a case study

Training health professionals within University environments has traditionally focused on face-to-face methods. Practitioners working within the UK National Health Service (NHS) have found it difficult to gain leave from work to attend for study due to the demands of the NHS and staff shortages. In response, we developed a distance e learning course to match our current traditional taught programme.The first e learning module (a research methods module) was comparable in content to the traditional taught module, and developed to incorporate a formative assessment design throughout; embodying the Constructivist approach and the principle of assessment for learning. We evaluated student experiences with the e learning module using a pre and post module questionnaire, with the taught cohort used as a comparison. We tested the importance of support, levels of information technology (IT) skills, preferences for e learning and intrinsic motivation. The results identified that highly satisfied e learning students were more likely to report a preference for e learning initially, show higher levels of intrinsic motivation and report good support from tutors and fellow students. This article discusses the development and evaluation of the pilot module and some of the lessons learned from providing e learning to health workers

Landforms predict phylogenetic structure on one of the world's most ancient surfaces

<p>Abstract</p> <p>Background</p> <p>The iconic Pilbara in northwestern Australia is an ancient geological and biophysical region that is an important zone of biodiversity, endemism and refugia. It also is overlain by some of the oldest erosion surfaces on Earth, but very little is known about the patterns of biotic diversity within the Pilbara or how they relate to the landscape. We combined phylogenetic and spatial-autocorrelation genetic analyses of mitochondrial DNA data on populations of the gekkotan lizard <it>Lucasium stenodactylum </it>within the Pilbara with geological, distributional and habitat data to test the hypothesis that ancient surface geology predicts current clade-habitat associations in saxicoline animals.</p> <p>Results</p> <p>This is the first detailed phylogenetic examination of a vertebrate organism across the Pilbara region. Our phylogeny provides strong support for a deep and ancient phylogenetic split within <it>L. stenodactylum </it>that distinguishes populations within the Pilbara region from those outside the Pilbara. Within the Pilbara region itself, our phylogeny has identified five major clades whose distribution closely matches different surface geologies of this ancient landscape. Each clade shows strong affinities with particular terrain types and topographic regions, which are directly related to different geological bedrock.</p> <p>Conclusion</p> <p>Together our phylogenetic, distributional, geological and habitat data provide a clear example of ecological diversification across an ancient and heterogeneous landscape. Our favoured hypothesis is that ancestors of the Pilbara lineages radiated into the region at the onset of aridity in Australia approximately 5 mya and locally adapted to the various ancient and highly stable terrain types and the micro-habitats derived from them. In terms of specimen recovery and analysis, we are only beginning to reconstruct the biotic history of this ancient landscape. Our results show the geological history and the habitats derived from them will form an important part of this emerging story.</p

Nuclear Cryogenic Propulsion Stage Affordable Development Strategy

The development of nuclear power for space use in nuclear thermal propulsion (NTP) systems will involve significant expenditures of funds and require major technology development efforts. The development effort must be economically viable yet sufficient to validate the systems designed. Efforts are underway within the National Aeronautics and Space Administration's (NASA) Nuclear Cryogenic Propulsion Stage Project (NCPS) to study what a viable program would entail. The study will produce an integrated schedule, cost estimate and technology development plan. This will include the evaluation of various options for test facilities, types of testing and use of the engine, components, and technology developed. A "Human Rating" approach will also be developed and factored into the schedule, budget and technology development approach