707 research outputs found

    Estimates in Beurling--Helson type theorems. Multidimensional case

    Full text link
    We consider the spaces Ap(Tm)A_p(\mathbb T^m) of functions ff on the mm -dimensional torus Tm\mathbb T^m such that the sequence of the Fourier coefficients f^={f^(k), k∈Zm}\hat{f}=\{\hat{f}(k), ~k \in \mathbb Z^m\} belongs to lp(Zm), 1≀p<2l^p(\mathbb Z^m), ~1\leq p<2. The norm on Ap(Tm)A_p(\mathbb T^m) is defined by ∄f∄Ap(Tm)=∄f^∄lp(Zm)\|f\|_{A_p(\mathbb T^m)}=\|\hat{f}\|_{l^p(\mathbb Z^m)}. We study the rate of growth of the norms ∄eiλφ∄Ap(Tm)\|e^{i\lambda\varphi}\|_{A_p(\mathbb T^m)} as âˆŁÎ»âˆŁâ†’âˆž, λ∈R,|\lambda|\rightarrow \infty, ~\lambda\in\mathbb R, for C1C^1 -smooth real functions φ\varphi on Tm\mathbb T^m (the one-dimensional case was investigated by the author earlier). The lower estimates that we obtain have direct analogues for the spaces Ap(Rm)A_p(\mathbb R^m)

    Atmospheric conditions and their effect on ball-milled magnesium diboride

    Full text link
    Magnesium diboride bulk pellets were fabricated from pre-reacted MgB2 powder ball milled with different amounts of exposure to air. Evidence of increased electron scattering including increased resistivity, depressed Tc, and enhanced Hc2 of the milled and heat treated samples were observed as a result of increased contact with air. These and other data were consistent with alloying with carbon as a result of exposure to air. A less clear trend of decreased connectivity associated with air exposure was also observed. In making the case that exposure to air should be considered a doping process, these results may explain the wide varibability of "undoped" MgB2 properties extant in the literature.Comment: Work presented at ASC 2006 in Seattl

    Absorbing boundary conditions for the Westervelt equation

    Full text link
    The focus of this work is on the construction of a family of nonlinear absorbing boundary conditions for the Westervelt equation in one and two space dimensions. The principal ingredient used in the design of such conditions is pseudo-differential calculus. This approach enables to develop high order boundary conditions in a consistent way which are typically more accurate than their low order analogs. Under the hypothesis of small initial data, we establish local well-posedness for the Westervelt equation with the absorbing boundary conditions. The performed numerical experiments illustrate the efficiency of the proposed boundary conditions for different regimes of wave propagation

    Positive youth development in swimming: clarification and consensus of key psychosocial assets

    Get PDF
    The purpose of this study was to gain a more cohesive understanding of the assets considered necessary to develop in young swimmers to ensure both individual and sport specific development. This two stage study involved (a) a content analysis of key papers to develop a list of both psychosocial skills for performance enhancement and assets associated with positive youth development, and (b) in-depth interviews involving ten expert swim coaches, practitioners and youth sport scholars. Five higher order categories containing seventeen individual assets emerged. These results are discussed in relation to both existing models of positive youth development and implications for coaches, practitioners and parents when considering the psychosocial development of young British swimmers

    Blueberry Research Progress Reports

    Get PDF
    The 1989 edition of the Blueberry Research Progress Reports was prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers with the Maine Agricultural Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include: 1. Control of Secondary Blueberry Pests 2. Monitory Methods, Economic Injury Levels, and Action Thresholds of Secondary Blueberry Pests 3. Control of Blueberry Maggot 4. Phosphorus Dose/Response Curve 5. Nitrogen-Phosphorus Study 6. Multiple Cropping of Wild Stands 7. Changes in Sugars and Organic Acids of Blueberries During Development 8. Investigation of Preprocess Changes That Could Lead to the Development of a Simple and Inexpensive Method to Measure Preprocess Berry Spoilage 9. Development of Simple and Less Expensive Methods to Analyze Pesticides Used on Maine and Canadian Blueberries 10. Evaluation and Modification of Commercial Wipers 11. Effect of Rate and Formulation of Hexazinone on Bunchberry 12. Bracken Fern Control Alternatives 13. Evaluation of Hexazinone with Spot Treatments of Glyphosate Sethoxydim or Fluazifop-P for Bunchgrass Control 14. Directed Sprays of Glyphosate for Bunchberry Control 15. Evaluation of Norflurazon with or without Hexazinone for Bunchgrass Control 16. Selective Wiper and Mechanical Control of Dogbane 17. Evaluation of Sulfonyl Urea Herbicides for Bunchberry Control 18. Seedling Pruning Study 19. Evaluation of Sethoxydim in Lowbush Blueberry Fields 20. Blueberry Extension Program 21. Pollination of the Low-bush Blueberry by Native Bees 22. Postharvest Fungi of Lowbush Blueberries 23. Effects of Pruning Methods on Mummy Berry Incidenc

    Remote Ischaemic Conditioning after Stroke Trial (RECAST): a pilot randomised placebo controlled phase II trial in acute ischaemic stroke (ISRCTN 86672015)

    Get PDF
    Background:Repeated episodes of limb ischaemia and reperfusion (remote ischaemic conditioning, RIC) may improve outcome after acute stroke.Methods:We performed a pilot blinded placebo-controlled trial in patients with acute ischaemic stroke, randomised 1:1 to receive four cycles of RIC within 24 hours of ictus. The primary outcome was tolerability and feasibility. Secondary outcomes included safety, clinical efficacy (day 90), putative biomarkers (pre- and post intervention, day 4) and exploratory haemodynamic measures.Findings:Twenty-six patients (13 RIC, 13 sham) were recruited 15.8 hours (SD 6.2) post onset, age 76·2 years (10.5), blood pressure 159/83mmHg (25/11) and NIHSS 5 [IQR 3.75-9.25]. RIC was well tolerated with 49/52 cycles completed in full. Three patients experienced vascular events in the sham group: two ischaemic strokes and two myocardial infarcts versus none in the RIC group (p=0·076, log-rank test). Compared to sham, there was a significant decrease in day 90 NIHSS in the RIC group, median NIHSS 1 [0.5-5] versus 3 [2-9.5], p=0.04; RIC augmented plasma heat shock protein (HSP) 27 (

    Maine Blueberry Advisory Committee Research Report

    Get PDF
    The 1990 edition of the Maine Blueberry Advisory Committee Research Reports was prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers with the Maine Agricultural Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include: 1. Biology and action thresholds of secondary blueberry pests 2. Control of blueberry maggot 3. Control of secondary blueberry pests 4. Application of steam as a method of controlling secondary pest insects on lowbush blueberry: a feasibility study 5. Pollination of the lowbush blueberry by native bees 6. Nitrogen-phosphorus study 7. Potassium study 8. Multiple cropping of wild stands 9. Phosphorus dose/response curve 10. Improvement in the color and texture of the canned blueberry 11. The effect of fertilization and irrigation on blueberry fruit quality 12. Investigation of preprocess changes (chemical, microbiological, and/or physical) that could lead to the development of a simple and inexpensive method to measure preprocess berry spoilage 13. The effect of postharvest handling on the dietary fiber and ellagic acid content of lowbush blueberries 14. Determination of pesticide residue levels in freshly harvested and processed lowbush blueberries 15. Evaluation of Defoliating Diseases 16. Vacuum Sanitation for Disease Control 17. Evaluation and modification of commercial herbicide applications 18. Evaluation of the suitability of remote sensing to evaluate plant cover in lowbush blueberry fields 19. Evaluation of Sethoxydin (POAST) in lowbush blueberry fields 20. Seedling pruning study 21. Evaluation of norflurazon (SOLICAM) with or without hexazinone (VELPAR) for bunchberry control 22. Selective wiper and mechanical control of dogbane and bracken fern 23. Evaluation of norflurazon (SOLICAM) in fall vs spring for oatgrass control 24. Evaluation of sulfonyl urea herbicides for bunchberry control 25. Evaluation of postemergence applications of DPX-L5300 for bunchberry control 26. Effect of time of application and formulation of hexazinone (VELPAR) on blueberry and bunchberry 27. Investigations of lowbush blueberry fruit-bud cold hardiness 28. The economics of investing in irrigation for lowbush blueberries 29. Effects of irrigation on lowbush blueberry yield and quality 30. Groundwater and surface water development for blueberry irrigation 31. Design, fabrication and testing of an experimental sterilizer for blueberry field
    • 

    corecore