60 research outputs found

    Nonspherically Symmetric Collapse in Asymptotically AdS Spacetimes

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    We numerically simulate gravitational collapse in asymptotically anti-de Sitter spacetimes away from spherical symmetry. Starting from initial data sourced by a massless real scalar field, we solve the Einstein equations with a negative cosmological constant in five spacetime dimensions and obtain a family of non-spherically symmetric solutions, including those that form two distinct black holes on the axis. We find that these configurations collapse faster than spherically symmetric ones of the same mass and radial compactness. Similarly, they require less mass to collapse within a fixed time

    Dimensional reduction in numerical relativity: Modified Cartoon formalism and regularization

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    We present in detail the Einstein equations in the Baumgarte-Shapiro-Shibata-Nakamura formulation for the case of DD dimensional spacetimes with SO(D−d)SO(D-d) isometry based on a method originally introduced in Ref.1. Regularized expressions are given for a numerical implementation of this method on a vertex centered grid including the origin of the quasi-radial coordinate that covers the extra dimensions with rotational symmetry. Axisymmetry, corresponding to the value d=D−2d=D-2, represents a special case with fewer constraints on the vanishing of tensor components and is conveniently implemented in a variation of the general method. The robustness of the scheme is demonstrated for the case of a black-hole head-on collision in D=7D=7 spacetime dimensions with SO(4)SO(4) symmetry.U.S. is supported by the H2020 ERC Consolidator Grant “Matter and strong-field gravity: New frontiers in Einstein’s theory” grant agreement No. MaGRaTh–646597, the H2020-MSCA-RISE-2015 Grant No. StronGrHEP-690904, the STFC Consolidator Grant No. ST/L000636/1, the SDSC Comet and TACC Stampede clusters through NSF-XSEDE Award Nos. PHY-090003, the Cambridge High Performance Computing Service Supercomputer Darwin using Strategic Research Infrastructure Funding from the HEFCE and the STFC, and DiRAC’s Cosmos Shared Memory system through BIS Grant No. ST/J005673/1 and STFC Grant Nos. ST/H008586/1, ST/K00333X/1. P.F. and S.T. are supported by the H2020 ERC Starting Grant “New frontiers in numerical general relativity” grant agreement No. NewNGR- 639022. P.F. is also supported by a Royal Society University Research Fellowship. W.G.C. and M.K. are supported by STFC studentships.This is the final version of the article. It first appeared from the World Scientific Publishing Company via http://dx.doi.org/10.1142/S021827181641013

    End Point of the Ultraspinning Instability and Violation of Cosmic Censorship

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    We determine the end point of the axisymmetric ultraspinning instability of asymptotically flat Myers-Perry black holes in D = 6 spacetime dimensions. In the nonlinear regime, this instability gives rise to a sequence of concentric rings connected by segments of black membrane on the rotation plane. The latter become thinner over time, resulting in the formation of a naked singularity in finite asymptotic time and hence a violation of the weak cosmic censorship conjecture in asymptotically flat higher-dimensional spaces.We thank Roberto Emparan for discussions and Juha JĂ€ykkĂ€ and Kacper Kornet for their technical support. We thank the grchombo team for the great collaboration. Part of the computations for this Letter were undertaken on the COSMOS Shared Memory system at DAMTP (University of Cambridge). COSMOS is operated on behalf of the STFC DiRAC HPC Facility and is funded by BIS National E-infrastructure capital Grant No. ST/ J005673/1 and STFC Grants No. ST/H008586/1, No. ST/ K00333X/1. We thankfully acknowledge the computer resources at MareNostrum and the technical support provided by Barcelona Supercomputing Center (FI-2016-3-0006 “New frontiers in numerical general relativity”). P. F. and S. T. are supported by the European Research Council Grant No. ERC-2014-StG 639022-NewNGR. P. F. is also supported by a Royal Society University Research Fellowship (Grant No. UF140319). M. K. is supported by an STFC studentship. L. L. is supported by NSERC, CIFAR and Perimeter Institute. This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie SkƂodowska-Curie Grant agreement No. 690904. P. F. and M. K. would like to thank Perimeter Institute for their hospitality during the final stages of this work. Research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development Canada, and by the Province of Ontario through the Ministry of Research and Innovation

    Crop Updates 2011 - Farming Systems

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    This session covers twelve papers from different authors: 1. Fallowing 50% of the farm each year – does it pay? Janette Drew and Rob Grima Department of Agriculture and Food 2. How crop sequences affect the productivity and resilience of cropping systems in two Western Australian environments, Bob French, Raj Malik, Mark Seymour, Department of Agriculture and Food 3. When is continuous wheat or barley sustainable? Christine Zaicou-Kunesch and Rob Grima Department of Agriculture and Food 4. Identifying constraints to bridging the yield gap, Glenn McDonald, Department of Agriculture and Food 5. Land constraints limiting wheat yields in the Bridging the Yield Gap project area, Brendan Nicholas and Dennis van Gool, Department of Agriculture and Food 6. Can livestock have a long-term role in no-till cropping systems? James Fisher1, Peter Tozer2, and Doug Abrecht3, 1DĂ©sirĂ©e Futures, York, WA, 2PRT Consulting, West Wyalong, NSW and 3Department of Agriculture and Food 7. Pros and cons of dry seeding to counter variable seasonal breaks, Michael Robertson1, Cameron Weeks2, Michael O’Connor1, Doug Abrecht3, Rob Grima3, Peter Newman3, 1CSIRO, 2PlanFarm, 3Department of Agriculture and Food 8. Defining economic optimum plant densities of open pollinated and hybrid canola in WA, Mark Seymour, Department of Agriculture and Food 9. Alternative uses for unproductive soils examined in the North Eastern Agricultural Region (NEAR), Mike Clarke and Andrew Blake, Department of Agriculture and Food MARKETS 10. What the world wants from Australian wheat, Gordon MacAulay, Principal Economist, BRI Australia, Emeritus Professor of Agricultural Economics, University of Sydney 11. Effect of lupin flour incorporation on the physical and sensory quality of pasta, Vijay Jayasena1,2 and Syed M. Nasar-Abbas1,2, 1Food Science and Technology, School of Public Health, Curtin Health Innovation Research Institute, Curtin University, 2Centre for Food and Genomic Medicine 12. Wheat quality requirements for Saudi Arabia: baking quality and blending potential of some Australian exporting grades, Larisa Cato1, Robert Loughman1 and Ken Quail2, 1Department of Agriculture and Food, 2BRI Australi

    Observations of open-ocean deep convection in the northwestern Mediterranean Sea: Seasonal and interannual variability of mixing and deep water masses for the 2007-2013 Period

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    We present here a unique oceanographic and meteorological data set focus on the deep convection processes. Our results are essentially based on in situ data (mooring, research vessel, glider, and profiling float) collected from a multiplatform and integrated monitoring system (MOOSE: Mediterranean Ocean Observing System on Environment), which monitored continuously the northwestern Mediterranean Sea since 2007, and in particular high‐frequency potential temperature, salinity, and current measurements from the mooring LION located within the convection region. From 2009 to 2013, the mixed layer depth reaches the seabed, at a depth of 2330m, in February. Then, the violent vertical mixing of the whole water column lasts between 9 and 12 days setting up the characteristics of the newly formed deep water. Each deep convection winter formed a new warmer and saltier “vintage” of deep water. These sudden inputs of salt and heat in the deep ocean are responsible for trends in salinity (3.3 ± 0.2 × 10−3/yr) and potential temperature (3.2 ± 0.5 × 10−3 C/yr) observed from 2009 to 2013 for the 600–2300 m layer. For the first time, the overlapping of the three “phases” of deep convection can be observed, with secondary vertical mixing events (2–4 days) after the beginning of the restratification phase, and the restratification/spreading phase still active at the beginning of the following deep convection event

    Crop Updates - 2003 Oilseeds

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    This session covers fifteen papers from different authors ACKNOWLEDGMENTS VARIETIES Large scale canola varietal evaluation in WA, Peter Nelson, Oilseeds WA Performance of IT and TT canola varieties in the medium and high rainfall agzones of WA 2001-02, Graham Walton, Hasan Zaheer and Paul Carmody, Department of Agriculture QUALITY Reproductive biology, cotyledon development and oil accumulation in canola, J.A. Fortescue and D.W. Turner, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia Plant and environmental factors affecting oil concentration in canola – a mini-review, D.W. Turner, School of Plant Biology, Faculty of Natural and Agricultural Sciences, The University of Western Australia Potential benefits from interspecific crosses between canola and ‘near canola’ quality Indian mustard, Janet Wroth, School of Plant Biology, The University of Western Australia (UWA), Wallace Cowling, School of Plant Biology, UWA and CBWA Pty Ltd, Anh-Van Pham, School of Mathematics and Statistics, UWA NUTRITION, AGRONOMY AND MACHINERY Timing of nitrogen application for producing canola grain and oil, R. F. Brennan, Department of Agriculture Managing canola for soil type and moisture stress, Paul Carmody and Hasan Zaheer Department of Agriculture Machinery lessons from 2002 – canola establishment, Glen Riethmuller, Greg Hamilton and Jo Hawksley, Department of Agriculture Machinery lessons from 2002 – harvesting short crops, Glen Riethmuller, Department of Agriculture Does increasing canola seeding rate reduce the competitiveness of grass weeds? Zaicou-Kunesch, C.M., Zaheer, S.H. and Eksteen, D, Department of Agriculture PESTS AND DISEASES Aphid damage to canola – not all cultivars are equal, Françoise A. Berlandier and Christiaan Valentine, Department of Agriculture Should we be worried about developing insecticide resistance in aphids? Owain Edwards, CSIRO Entomology Benefits provided by treating canola seed with imidacloprid seed dressing, Roger Jones, Brenda Coutts, Lisa Smith and Jenny Hawkes, Department of Agriculture, and Centre for Legumes in Mediterranean Agriculture Blackleg levels in canola in 2002, Ravjit Khangura1, Moin Salam1, Art J Diggle1 and Martin J Barbetti1,2 1Department of Agriculture, 2University of Western Australia DBM in canola, Kevin Walden, Department of Agricultur

    Crop Updates 2009 - Cereals

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    This session covers twenty seven papers from different authors: PLENARY 1. Building soil carbon for productivity and implications for carbon accounting, Jeff Baldock, CSIRO Land and Water, Adelaide, SA 2. Fact or Fiction: Who is telling the truth and how to tell the difference, Doug Edmeades, agKnowledge Ltd, Hamilton 3. Four decades of crop sequence trials in Western Australia, Mark Seymour,Department of Agriculture and Food BREAK CROPS 4. 2008 Break Crops survey Report, Paul Carmody,Development Officer, Department of Agriculture and Food 5. Attitudes of Western Australian wheatbelt growers to ‘Break Crops’, Paul Carmody and Ian Pritchard, Development Officers, Department of Agriculture and Food 6. The value of organic nitrogen from lupins, Alan Meldrum, Pulse Australia 7.The area of break crops on farm: What farmers are doing compared to estimates based on maximising profit, Michael Robertson and Roger Lawes,CSIRO Floreat, Rob Sands,FARMANCO Farm Consultants, Peter White,Department of Agriculture and Food, Western Australia, Felicity Byrne and Andrew Bathgate,Farming Systems Analysis CROP SPECIFIC Breeding 8. Identification of WALAB2014 as a potential albus lupin variety for northern agricultural region of Western Australia, Kedar Adhikari, Department of Agriculture and Food 9. Enhancement of black spot resistance in field pea, Kedar Adhikari, Tanveer Khan, Stuart Morgan and Alan Harris, Department of Agriculture and Food 10. Desi chickpea breeding: Evaluation of advanced line, Khan, TN1, Harris, A1, Gaur, P2, Siddique, KHM3, Clarke, H4, Turner, NC4, MacLeod, W1, Morgan, S1 1Department of Agriculture and Food, Western Australia, 2International Crop Research Institute for the Semi Arid Tropics (ICRISAT), 3The University of Western Australia, 4Centre for Legumes in Mediterranean Agriculture 11. Pulse Breeding Australia-Australian Field Pea Improvement Program (AFPIP), Ian Pritchard1, Chris Veitch1, Stuart Morgan1, Alan Harris1 and Tony Leonforte 2 1 Department of Agriculture and Food, Western Australia, 2 Department off Primary Industries, Victoria Disease 12. Interaction between wheat varieties and fungicides to control stripe rust for grain and quality, Kith Jayasena, Geoff Thomas, Rob Loughman, Kazue Tanaka and Bill MacLeod, Department of Agriculture and Food 13. Findings of canola disease survey 2008 and its implications for better disease management in 2009, Ravjit Khangura, WJ MacLeod, P White, P Carmody and M Amjad, Department of Agriculture and Food 14. Combating wheat leaf diseases using genome sequencing and functional genomics, Richard Oliver, Australian Centre for Necrotrophic Fungal Pathogens, Murdoch University 15. Distribution and survival of wheat curl mite (Aceria tosichella), vector of Wheat Streak Mosaic Virus, in the WA grainbelt during 2008, Dusty Severtson, Peter Mangano, John Botha and Brenda Coutts, Department of Agriculture and Food 16. Partial resistance to Stagonspora (Septoria) Partial resistance to Stagonospora (Septoria) nodorum blotch and response to fungicide in a severe epidemic scenario, Manisha Shankar1, Richard Oliver2, Kasia Rybak2and Rob Loughman1 1Department of Agriculture and Food, Western Australia, 2Australian Centre for Necrotrophic Fungal Pathogens, Murdoch University, Western Australia 17. Black pod syndrome in lupins can be reduced by regular insecticide sprays, Peter White and Michael Baker,Department of Agriculture and Food Variety performance 18. Incorporating new herbicide tolerant juncea canola into low rainfall cropping systems in Western Australia, Mohammad Amjad, Department of Agriculture and Food 19. Varietal differences in germ end staining of barley, Andrea Hills,Department of Agriculture and Food 20. Wheat variety performance in the Central Agricultural Region in 2008, Shahajahan Miyan, Department of Agriculture and Food 21. Barley variety identification using DNA fingerprinting, Peter Portmann, Agriconnect, Perth WA Dr Nicole Rice, Southern Cross University, Lismore NSW Prof Robert Henry, Southern Cross University, Lismore NSW 22. Forecast disease resistance profile for the Western Australian barley crop over the next three years, Jeff J. Russell, Department of Agriculture and Food 23. Malting barley varieties differ in their flowering date and their response to changes in sowing date, BH Paynter and Jeff J. Russell,Department of Agriculture and Food 24. Market development for new barley varieties, Linda Price,Barley Australia 25. Response of wheat varieties to sowing time at Mt Barker, Katanning and Newdegate in 2008, Brenda Shackley and Vicki Scanlan,Department of Agriculture and Food 26. Flowering dates of wheat varieties in 2008 at three locations in Western Australia, Darshan Sharma, Brenda Shackley and Christine Zaicou-Kunesch, Department of Agriculture and Food 27. Agronomic responses of new wheat varieties in the norther agricultural region in 2008, Christine Zaicou-Kunesch, Department of Agriculture and Foo

    A parsimonious oscillatory model of handwriting

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    International audienceWe propose an oscillatory model that is theoretically parsimonious, empirically efficient and biologically plausible. Building on Hollerbach’s (Biol Cybern 39:139–156, 1981) model, our Parsimonious Oscillatory Model of Handwriting (POMH) overcomes the latter’s main shortcomings by making it possible to extract its parameters from the trace itself and by reinstating symmetry between the x and y coordinates. The benefit is a capacity to autonomously generate a smooth continuous trace that reproduces the dynamics of the handwriting movements through an extremely sparse model, whose efficiency matches that of other, more computationally expensive optimizing methods. Moreover, the model applies to 2D trajectories, irrespective of their shape, size, orientation and length. It is also independent of the endeffectors mobilized and of the writing direction

    Somatosensory processing in neurodevelopmental disorders

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    The purpose of this article is to review the role of somatosensory perception in typical development, its aberration in a range of neurodevelopmental disorders, and the potential relations between tactile processing abnormalities and central features of each disorder such as motor, communication, and social development. Neurodevelopmental disorders that represent a range of symptoms and etiologies, and for which multiple peer-reviewed articles on somatosensory differences have been published, were chosen to include in the review. Relevant studies in animal models, as well as conditions of early sensory deprivation, are also included. Somatosensory processing plays an important, yet often overlooked, role in typical development and is aberrant in various neurodevelopmental disorders. This is demonstrated in studies of behavior, sensory thresholds, neuroanatomy, and neurophysiology in samples of children with Fragile X syndrome, autism spectrum disorders (ASD), attention deficit hyperactivity disorder (ADHD), and cerebral palsy (CP). Impaired somatosensory processing is found in a range of neurodevelopmental disorders and is associated with deficits in communication, motor ability, and social skills in these disorders. Given the central role of touch in early development, both experimental and clinical approaches should take into consideration the role of somatosensory processing in the etiology and treatment of neurodevelopmental disorders
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