212 research outputs found
Liouville theorem for Beltrami flow
No full textInternational audienceThe author proves that if v∈C1(ℝ3) is a Beltrami solution of the stationary Euler equations v∇v+∇p=0,∇⋅v=0, and v∈Lp(ℝ3) or v(x)=o(1|x|) as x→∞, then v≡0
Thermodynamic and hydrological drivers of the subsurface thermal regime in Central Spain: open data and code
No full textQuality controlled temperature data at daily resolution at CTS, HRR, HYS, NVC, RSI and SGV and the most relevant codes for data processing used in:
García-Pereira, F., González-Rouco, J. F., Schmid, T., Melo-Aguilar, C, Vegas-Cañas, C., Steinert, N. J., Roldán-Gómez, P. J., Cuesta-Valero, F. J., García-García, A., Beltrami, H., and de Vrese, H.: "Thermodynamic and hydrological drivers of the subsurface thermal regime in Central Spain". Earth Surf. Dynam., submitted, 2023.
All data can be also freely obtained for research from the original data sources, GuMNet (https://www.ucm.es/gumnet/) and AEMET (https://www.aemet.es/en/datos_abiertos). Further details of the code are available upon request to the corresponding author (Félix García-Pereira, [email protected])
General Beltrami equations and BMO
No full textWe study the Beltrami equations ∂f = μ(z)∂f + ν(z)∂f under the assumption that the coefficients μ, ν satisfy the inequality |μ| + |ν| < 1 almost everywhere. Sufficient conditions for the existence of homeomorphic ACL solutions to the Beltrami equations are given in terms of the bounded mean oscillation by John and Nirenberg.The research of the third author was partially supported by the Ukrainian State Foundation of Fundamental Investigations (FFI), Grant number F25.1/055
General Beltrami equations and BMO
No full textWe study the Beltrami equations ∂f = μ(z)∂f + ν(z)∂f under the assumption that the coefficients μ, ν satisfy the inequality |μ| + |ν| < 1 almost everywhere. Sufficient conditions for the existence of homeomorphic ACL solutions to the Beltrami equations are given in terms of the bounded mean oscillation by John and Nirenberg.The research of the third author was partially supported by the Ukrainian State Foundation of Fundamental Investigations (FFI), Grant number F25.1/055
General Beltrami equations and BMO
No full textWe study the Beltrami equations ∂f = μ(z)∂f + ν(z)∂f under the assumption that the coefficients μ, ν satisfy the inequality |μ| + |ν| < 1 almost everywhere. Sufficient conditions for the existence of homeomorphic ACL solutions to the Beltrami equations are given in terms of the bounded mean oscillation by John and Nirenberg.The research of the third author was partially supported by the Ukrainian State Foundation of Fundamental Investigations (FFI), Grant number F25.1/055
Long-term global ground heat flux and continental heat storage from geothermal data
No full text© Author(s) 2021. We are grateful for two anonymous reviewers and their thoughtful and constructive feedback. This analysis contributes to the PALEOLINK project (http://pastglobalchanges. org/science/wg/2knetwork/projects/paleolink/intro, last access: 16 February 2021), part of the PAGES 2k Network. Hugo Beltrami was supported by the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chairs Program, and the Canada Foundation for Innovation. Hugo Beltrami holds the Canada Research Chair in Climate Dynamics. Almudena García-García and Francisco José Cuesta-Valero were funded by Hugo Beltrami’s Canada Research Chair program, the School of Graduate Students at the Memorial University of Newfoundland, and the Research Office at St. Francis Xavier University. This research has been supported by the Natural Sciences and Engineering Research Council of Canada (grant no. NSERC DG 140576948) and the Canada Research Chairs (grant no. CRC 230687).Energy exchanges among climate subsystems are of critical importance to determine the climate sensitivity of the Earth’s system to greenhouse gases, to quantify the magnitude and evolution of the Earth’s energy imbalance, and to project the evolution of future climate. Thus, ascertaining the magnitude of and change in the Earth’s energy partition within climate subsystems has become urgent in recent years. Here, we provide new global estimates of changes in ground surface temperature, ground surface heat flux, and continental heat storage derived from geothermal data using an expanded database and new techniques. Results reveal markedly higher changes in ground heat flux and heat storage within the continental subsurface than previously reported, with land temperature changes of 1 K and continental heat gains of around 12 ZJ during the last part of the 20th century relative to preindustrial times. Half of the heat gain by the continental subsurface since 1960 has occurred in the last 20 years.Natural Sciences and Engineering Research Council of CanadaCanada Research Chairs ProgramDepto. de Física de la Tierra y AstrofísicaFac. de Ciencias FísicasTRUEpu
Carlo Levi e l’edizione americana dell’"Orologio". Ricognizione su alcune carte d’archivio
No full textPubblicata nel 1951 dagli editori newyorkesi Farrar, Straus & Young, l’edizione americana dell’Orologio ha avuto una gestazione complicata da numerosi problemi di traduzione. Alcune lettere inedite spedite dall’editore John Farrar all’autore tra il 15 marzo e il 14 maggio 1951 e conservate presso Fondo Carlo Levi di Alassio permettono di aggiungere qualche nuovo elemento sulla storia redazionale del libro e sui rapporti di Levi con il mondo editoriale e culturale statunitense.
Published in New York by Farrar, Straus & Young in 1951, The Watch had some troubles about the english translation. Some letters sent by John Farrar to the author between March 15 and May 14 1951 and kept in the Archive Carlo Levi of Alassio add some new detail about the editorial history of the book and about the Levi’s relations with U.S. publishing and culture
Marcinkiewicz exponents and jump problem for Beltrami equation
No full text© 2017, Allerton Press, Inc.Marcinkiewicz exponents that were introduced by the author before are applied here to solving boundary-value jump problem on non-rectifiable curve for one special case of the Beltrami equation
Marcinkiewicz exponents and jump problem for Beltrami equation
No full text© 2017, Allerton Press, Inc.Marcinkiewicz exponents that were introduced by the author before are applied here to solving boundary-value jump problem on non-rectifiable curve for one special case of the Beltrami equation
The Hierarchical Subspace Iteration Method for Laplace–Beltrami Eigenproblems
No full textSparse eigenproblems are important for various applications in computer graphics. The spectrum and eigenfunctions of the Laplace–Beltrami operator, for example, are fundamental for methods in shape analysis and mesh processing. The Subspace Iteration Method is a robust solver for these problems. In practice, however, Lanczos schemes are often faster. In this article, we introduce the Hierarchical Subspace Iteration Method (HSIM), a novel solver for sparse eigenproblems that operates on a hierarchy of nested vector spaces. The hierarchy is constructed such that on the coarsest space all eigenpairs can be computed with a dense eigensolver. HSIM uses these eigenpairs as initialization and iterates from coarse to fine over the hierarchy. On each level, subspace iterations, initialized with the solution from the previous level, are used to approximate the eigenpairs. This approach substantially reduces the number of iterations needed on the finest grid compared to the non-hierarchical Subspace Iteration Method. Our experiments show that HSIM can solve Laplace–Beltrami eigenproblems on meshes faster than state-of-the-art methods based on Lanczos iterations, preconditioned conjugate gradients, and subspace iterations.Computer Graphics and Visualisatio
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