228 research outputs found

    Modelling of atmospheric boundary layer: Generation of shear.

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    Roughness length, z0 and friction velocity, u* are the defining parameters of wind log profile that must be matched in wind tunnel simulation. To fully understand the role of these parameters, the basics and review from the primitive equations and its relation to the logarithmic profile obtained for wind tunnel conditions were discussed. The problem of roughness, although well known, still needs to be addressed more rigorously especially when determining values of z0 and u* from wind tunnel data and their relation to the roughness element geometry. A review of classic literature and new published material were carried out, focusing on the applicability to wind tunnel modelling

    Transverse component of the magnetic field in the solar photosphere observed by Sunrise

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    We present the first observations of the transverse component of photospheric magnetic field acquired by the imaging magnetograph Sunrise/IMaX. Using an automated detection method, we obtain statistical properties of 4536 features with significant linear polarization signal. Their rate of occurrence is 1-2 orders of magnitude larger than values reported by previous studies. We show that these features have no characteristic size or lifetime. They appear preferentially at granule boundaries with most of them being caught in downflow lanes at some point in their evolution. Only a small percentage are entirely and constantly embedded in upflows (16%) or downflows (8%).Comment: Accepted for the Sunrise Special Issue of ApJ

    The StaggerGrid Project: a Grid of 3D Model Atmospheres for High-Precision Spectroscopy

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    In this contribution, we present the StaggerGrid, a collaborative project for the construction of a comprehensive grid of time-dependent, three-dimensional (3D), hydrodynamic model atmospheres of solar- and late-type stars with different effective temperatures, surface gravities, and chemical compositions. We illustrate the main characteristics of these 3D models and their effects on the predicted strengths, wavelength-shifts, and shapes of spectral lines, highlighting the differences with respect to calculations based on classical, one-dimensional, hydrostatic models, and discuss some of their possible applications to elemental abundance analysis of stellar spectra in the context of large observational surveys.Comment: Accepted for publication in the Journal of Physics, Conference Series. Proceedings of the GREAT-ESF Workshop on "Stellar Atmospheres in the Gaia Era.

    Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

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    The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review

    Health-related quality of life in preschool children in five health conditions

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    Objective: To test the responsiveness of the Infant/Toddler Quality of Life Questionnaire (ITQOL) to five health conditions. In addition, to evaluate the impact of the child's age and gender on the ITQOL domain scores. Methods: Observational study of 494 Dutch preschool-aged children with five clinical conditions and 410 healthy preschool children randomly sampled from the general population. The clinical conditions included neurofibromatosis type 1, wheezing illness, bronchiolitis, functional abdominal complaints, and burns. Health-related quality of life (HRQoL) was assessed by a mailed parent-completed ITQOL. Mean ITQOL scale scores for all conditions were compared with scores obtained from the reference sample. The effect of patient's age and gender on ITQOL scores was assessed using multi-variable regression analysis. Results: In all health conditions, substantially lower scores were found for several ITQOL scales. The conditions had a variable effect on the type of ITQOL domains and a different magnitude of effect. Scores for 'physical functioning', 'bodily pain', and 'general health perceptions' showed the greatest range. Parental impact scales were equally affected by all conditions. In addition to disease type, the child's age and gender had an impact on HRQoL. Conclusions: The five health conditions (each with a distinct clinical profile) affected the ITQOL scales differently. These results indicate that the ITQOL is sensitive to specific characteristics and symptom expression of the childhood health conditions investigated. This insight into the sensitivity of the ITQOL to health conditions with different symptom expression may help in the interpretation of HRQoL results in future applications

    Crop Updates - 2003 Pulses

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    This session covers fifty one papers from different authors 2002 PULSE INDUSTRY HIGHLIGHTS CONTRIBUTORS BACKGROUND 2002 REGIONAL ROUNDUP 1.Northern Agricultural Region, M. Harries, Department of Agriculture 2.Central agricultural Region, R. French and I. Pritchard, Department of Agriculture 3.Great Southern and Lakes, R. Beermier, N. Poulish and S. White, Department of Agriculture 4.Esperance Mallee, M. Seymour, Department of Agriculture PULSE PRODUCTION ECONOMY AND GENETIC IMPROVEMENT 5.Faba Bean, P. White, Department of Agriculture 6.Germplasm evaluation, P. White, T. Pope, M. Harries and M. Seymour, Department of Agriculture 7.Row spacing and sowing rate, M. Seymour, Department of Agriculture 8.Tolerance to post emergent herbicides, M. Seymour, M. Harries, R. Beermier, M. Blyth and L. Young, Department of Agriculture 9.Investigation of environmental staining and storage discolouration, N. Abbas1,2, J. Plummer1, P. White3, D. Harris4 and K. Siddique1,2, 1Plant Biology, The University of Western Australia, 2CLIMA, The University of Western Australia, 3Department of Agriculture, 4Chemistry Centre of Western Australia. Desi chickpea 10.Breeding highlights, T. Khan1,2 and K. Siddique2 1Department of Agriculture, 2CLIMA, The University of Western Australia 11. Variety evaluation, T. Khan and K. Regan, Department of Agriculture 12. Residual effect of chickpea row spacing and sowing rate on wheat yield, G. Riethmuller and B. MacLeod, Department of Agriculture 13. Genotype x environmental interaction studies to help explain adaptation, J. Berger1, N. Turner1,2, K. Siddique1, 1CLIMA, The University of Western Australia, 2CSIRO Plant Industry 14. Genetic characterisation of wild relatives, F. Shan and H. Clarke, CLIMA, The University of Western Australia 15. Tolerance to chilling at flowering, H. Clarke, CLIMA, The University of Western Australia 16. Kabuli chickpea, K. Regan, Department of Agriculture 17. Premium quality varieties for the Ord River Irrigation Area, K. Siddique1, K. Regan2 and P. Smith2 1CLIMA, The University of Western Australia, 2Department of Agriculture 18. Development of aschochyta resistant varieties for Australia, K. Siddique1, K. Regan2 and M. Baker2 1CLIMA, University of Western Australia, 2Department of Agriculture Field pea 19. Breeding highlights, T. Khan and B. French, Department of Agriculture 20. Variety evaluation, T. Khan, Department of Agriculture 21. Specialty types for the high rainfall regions, P. White and T. Khan, Department of Agriculture 22. Are new varieties more sensitive to delayed sowing than Dundale? R. French, M. Seymour and R. Beermier, Department of Agriculture 23. Does the size of sown seed affect seed size and yield at harvest? R. Beermier and N. Poulish, Department of Agriculture 24. Tolerance to post emergent herbicides, H. Dhammu, T. Piper and D. Nicholson, Department of Agriculture 25. Lentil, K. Regan, Department of Agriculture 26. Variety evaluation, K. Regan and M. Harries, Department of Agriculture 27. Interstate evaluation of advanced breeding lines, K. Regan1 and M. Materne2 1Department of Agriculture, 2Victorian Institute for Dryland Agriculture, Agriculture Victoria 28. Timing of harvest for the best seed yield, M. Harries and M. Blyth, Department of Agriculture 29. Tolerance to post emergent herbicides, M. Harries and D. Nicholson, Department of Agriculture, H. Dhammu, T. Piper and L. Young, Department of Agriculture 30. Row spacing and stubble, G. Riethmuller, Department of Agriculture Pulse species 31. High value pulses for the high rainfall areas, N. Poulish1, P. White1,2 and K. Siddique1,2 , 1Department of Agriculture, 2CLIMA, The University of Western Australia 32. Alternative Rhizobium inoculant carrier technologies, J. Howieson and R. Yates, Centre for Rhizobium Studies (CRS), Murdoch University 33. Time of harvest to improve seed yield and quality of pulses, G. Riethmuller and R. French, Department of Agriculture 34. Phosphorus and zinc responses in pulses, S. Loss1, Z. Rengel2, B. Bowden3, M. Bolland3 and K. Siddique4 , 1Wesfarmers CSBP, 2Soil Science and Plant Nutrition, The University of Western Australia, 3Department of Agriculture, 4CLIMA, The University of Western Australia 35. Robust protocols for doubled haploid production in field pea and chickpea, J. Croser and K. Siddique, CLIMA, The University of Western Australia DEMONSTRATION OF PULSES IN THE FARMING SYSTEM 36. Field pea and lentil on clayed sandplain, M. Seymour, Department of Agriculture 37. Field pea variety demonstration, M. Harries and M. Blyth, Department of Agriculture 38. The benefit of field peas compared to lupins, R. Beermier, Department of Agriculture DISEASE AND PEST MANAGEMENT 39. Ascochyta blight of chickpea, B. MacLeod, Department of Agriculture 40. Management of chickpeas with improved ascochyta resistance, B. Macleod, A. Harrod, M. Harries and M. Blyth, Department of Agriculture 41. Chlorothalonil provides the most effective control, B. Macleod, A. Harrod, M. Harries and M. Blyth, Department of Agriculture 42. Importance of early sprays and value of seed dressing (post emergence), B. Macleod and A. Harrod, Department of Agriculture 43. A windborne stage of ascochyta blight in WA, J. Galloway and B. MacLeod, Department of Agriculture Ascochyta disease of pulses 44. Geographic location effects ascochyta spore maturation on pulse stubble, J. Galloway and B. MacLeod, Department of Agriculture Blackspot of field pea 45. Rapid recurrent selection to improve resistance to black spot, C. Beeck1, J. Wroth1, W. Cowling1 and T. Khan2, 1Plant Science, The University of Western Australia, 2Department of Agriculture 46. Survival of blackspot on old field pea stubble, J. Galloway and B. MacLeod, Department of Agriculture 47. Blackspot spores mature earlier in the southern regions, M. Salam, J. Galloway, A. Diggle and B. MacLeod, Department of Agriculture Viruses in pulses 48. Early insecticide application suppresses spread of Beet Western Yellows virus in field pea, R. Jones, B. Coutts and L. Smith, Department of Agriculture, and CLIMA, The University of Western Australia Insect pests and nematodes 49. Incorporation of pea weevil resistance from Pisum fulvum into field pea, O. Byrne1 and D. Hardie2, 1CLIMA, The University of Western Australia 2Department of Agriculture 50. Resistance to Helicoverpa in wild species of chickpea, J. Ridsdill-Smith1, H. Sharma2 and K. Mann1, 1CSIRO Entomology, Western Australia, 2 ICRISAT, Hyderabad, India 51. Relative hosting ability of field pea genotypes to root lesion nematode, S. Kelly, S. Sharma, H. Hunter and V. Vanstone, Department of Agriculture ACKNOWLEDGEMENTS APPENDIX I: Publications by Pulse Productivity Project Staff 2002 APPENDIX II: Summary of previous results APPENDIX III: List of common acronym

    NS2 Protein of Hepatitis C Virus Interacts with Structural and Non-Structural Proteins towards Virus Assembly

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    Growing experimental evidence indicates that, in addition to the physical virion components, the non-structural proteins of hepatitis C virus (HCV) are intimately involved in orchestrating morphogenesis. Since it is dispensable for HCV RNA replication, the non-structural viral protein NS2 is suggested to play a central role in HCV particle assembly. However, despite genetic evidences, we have almost no understanding about NS2 protein-protein interactions and their role in the production of infectious particles. Here, we used co-immunoprecipitation and/or fluorescence resonance energy transfer with fluorescence lifetime imaging microscopy analyses to study the interactions between NS2 and the viroporin p7 and the HCV glycoprotein E2. In addition, we used alanine scanning insertion mutagenesis as well as other mutations in the context of an infectious virus to investigate the functional role of NS2 in HCV assembly. Finally, the subcellular localization of NS2 and several mutants was analyzed by confocal microscopy. Our data demonstrate molecular interactions between NS2 and p7 and E2. Furthermore, we show that, in the context of an infectious virus, NS2 accumulates over time in endoplasmic reticulum-derived dotted structures and colocalizes with both the envelope glycoproteins and components of the replication complex in close proximity to the HCV core protein and lipid droplets, a location that has been shown to be essential for virus assembly. We show that NS2 transmembrane region is crucial for both E2 interaction and subcellular localization. Moreover, specific mutations in core, envelope proteins, p7 and NS5A reported to abolish viral assembly changed the subcellular localization of NS2 protein. Together, these observations indicate that NS2 protein attracts the envelope proteins at the assembly site and it crosstalks with non-structural proteins for virus assembly

    Distribution of Attention Modulates Salience Signals in Early Visual Cortex

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    Previous research has shown that the extent to which people spread attention across the visual field plays a crucial role in visual selection and the occurrence of bottom-up driven attentional capture. Consistent with previous findings, we show that when attention was diffusely distributed across the visual field while searching for a shape singleton, an irrelevant salient color singleton captured attention. However, while using the very same displays and task, no capture was observed when observers initially focused their attention at the center of the display. Using event-related fMRI, we examined the modulation of retinotopic activity related to attentional capture in early visual areas. Because the sensory display characteristics were identical in both conditions, we were able to isolate the brain activity associated with exogenous attentional capture. The results show that spreading of attention leads to increased bottom-up exogenous capture and increased activity in visual area V3 but not in V2 and V1

    Shifting Attention within Memory Representations Involves Early Visual Areas

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    Prior studies have shown that spatial attention modulates early visual cortex retinotopically, resulting in enhanced processing of external perceptual representations. However, it is not clear whether the same visual areas are modulated when attention is focused on, and shifted within a working memory representation. In the current fMRI study participants were asked to memorize an array containing four stimuli. After a delay, participants were presented with a verbal cue instructing them to actively maintain the location of one of the stimuli in working memory. Additionally, on a number of trials a second verbal cue instructed participants to switch attention to the location of another stimulus within the memorized representation. Results of the study showed that changes in the BOLD pattern closely followed the locus of attention within the working memory representation. A decrease in BOLD-activity (V1–V3) was observed at ROIs coding a memory location when participants switched away from this location, whereas an increase was observed when participants switched towards this location. Continuous increased activity was obtained at the memorized location when participants did not switch. This study shows that shifting attention within memory representations activates the earliest parts of visual cortex (including V1) in a retinotopic fashion. We conclude that even in the absence of visual stimulation, early visual areas support shifting of attention within memorized representations, similar to when attention is shifted in the outside world. The relationship between visual working memory and visual mental imagery is discussed in light of the current findings
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