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Alignments of parity even/odd-only multipoles in CMB

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arXiv 2017年

作者： Aluri, Pavan K. Ralston, John P. Weltman, Amanda Cosmology & Gravity Group Department of Mathematics and Applied Mathematics University of Cape Town Rondebosch7700 South Africa Department of Physics and Astronomy University of Kansas LawrenceKS66045 United States Institute for Advanced Study PrincetonNJ08540 United States Center for Computational Astrophysics Flatiron Institute 162 Fifth Avenue New YorkNY United States

We compare the statistics of parity even and odd multipoles of the cosmic microwave background (CMB) sky from PLANCK full mission temperature measurements. An excess power in odd multipoles compared to even multipoles has previously been found on large angular scales. Motivated by this apparent parity asymmetry, we evaluate directional statistics associated with even compared to odd multipoles, along with their significances. Primary tools are the Power Tensor and Alignment Tensor *** limit our analysis to the first sixty multipoles i.e., l = [2;61]. We find no evidence for statistically unusual alignments of even parity multipoles. More than one independent statistic finds evidence for alignments of anisotropy axes of odd multipoles, with a significance equivalent to 2 or more. The robustness of alignment axes is tested by making galactic cuts and varying the multipole range. Very interestingly, the region spanned by the (a)symmetry axes is found to broadly contain other parity (a)symmetry axes previously observed in the literature. Copyright © 2017, The Authors. All rights reserved.

关键词： Alignment

The solar dynamo begins near the surface

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arXiv 2024年

作者： Vasil, Geoffrey M. Lecoanet, Daniel Augustson, Kyle Burns, Keaton J. Oishi, Jeffrey S. Brown, Benjamin P. Brummell, Nicholas Julien, Keith School of Mathematics The Maxwell Institute for Mathematical Sciences University of Edinburgh EH9 3FD United Kingdom Department of Engineering Sciences and Applied Mathematics Northwestern University EvanstonIL60208 United States CIERA Northwestern University EvanstonIL60201 United States Department of Mathematics Massachusetts Institute of Technology CambridgeMA02139 United States Center for Computational Astrophysics Flatiron Institute New YorkNY10010 United States Department of Physics & Astronomy Bates College LewistonME04240 United States Department of Astrophysical and Planetary Sciences University of Colorado Boulder BoulderCO80309 United States Department of Applied Mathematics Jack Baskin School of Engineering University of California Santa Cruz Santa CruzCA95064 United States Department of Applied Mathematics University of Colorado Boulder BoulderCO80309 United States

The Sun's magnetic dynamo cycle features a distinct pattern: a propagating region of sunspot emergence appears around 30° latitude and vanishes near the equator every 11 years. Moreover, longitudinal flows called "torsional oscillations" closely shadow sunspot migration, undoubtedly sharing a common cause2. Contrary to theories suggesting deep origins for these phenomena, helioseismology pinpoints low-latitude torsional oscillations to the Sun's outer 5-10%, the "Near-Surface Shear Layer"3,4. Within this zone, inwardly increasing differential rotation coupled with a poloidal magnetic field strongly implicates the Magneto-Rotational Instability5,6 renowned in accretion-disk theory and observed in laboratory experiments7. Together, these two facts prompt the general question: Is it possible that the solar dynamo is a nearsurface instability? Here, we report strong affirmative evidence in stark contrast to traditional paradigms8 focusing on the deeper tachocline. Simple analytic estimates show that the near-surface magneto-rotational instability better explains the spatiotemporal scales of the torsional oscillations and inferred subsurface magnetic field amplitudes9. State-of-the-art numerical simulations corroborate these estimates and, strikingly, reproduce hemispherical magnetic current helicity laws10. The dynamo resulting from a well-understood near-surface phenomenon improves prospects for accurate predictions of full magnetic cycles and space weather, impacting Earth's electromagnetic infrastructure. © 2024, CC BY.

关键词： Magnetos

The total phenolic and flavonoid contents of Aloe vera and Morinda citrifolia extracts as antibacterial material against Pseudomonas aeruginosa

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Materials Today: Proceedings 2023年 72卷 2796-2802页

作者： Royani, Ahmad Hanafi, Muhammad Julistiono, Heddy Manaf, Azwar Postgraduate Program of Materials Science Study Department of Physics Faculty of Mathematics and Natural Sciences Universitas Indonesia Depok 16424 Indonesia Research Center for Metallurgy National Research and Innovation Agency Puspiptek Area Tangerang Selatan 15314 Indonesia Research Center for Raw Material of Medicine and Traditional Medicine National Research and Innovation Agency Puspiptek Area Tangerang Selatan 15314 Indonesia Research Center for Applied Microbiology National Research and Innovation Agency Jl. Raya Bogor Km. 46 Cibinong Science Center Cibinong 16911 Indonesia

Pseudomonas aeruginosa is a pioneer bacterium initiating the biofilm formation process so that it is corrosive to some metals in the marine environment. One of the efforts to prevent and control corrosion due to environmentally friendly biofilms is using green biocides. The extraction of Aloe vera and Morinda citrifolia with methanol were carried out to obtain antibacterial material. The extract of those plants with multilevel maceration method. The study aimed to identify the total phenolic and flavonoid contents in A. vera and M. citrifolia crude extracts and compare the two antibacterial extract activities. The total phenolic and flavonoid contents were analyzed using the Folin-Ciocalteu and the aluminum chloride colorimetric methods. The antibacterial activity against P. aeruginosa was conducted using the microdilution method to determine the minimum inhibitory concentration (MIC). The structure of the bioactive components of both A. vera and M. citrifolia extracts were identified using a liquid chromatography-mass spectrometer (LC/MS-MS). The MIC of A. vera and M. citrifolia for P. aeruginosa bacteria is about 6144 µg/mL, while the MIC of antibiotic Enrofloxacin is 16 µg/mL. The mean of total phenolic and flavonoid contents for the methanolic extracts of A. vera and M. citrifolia were 1.39% and 4.03% (phenolic), and 0.26% and 0.28% (flavonoids), respectively. The chemical structure of A. vera consists of 2″-O-Feruloylaloesin, Kaempferol-3-O-rutinoside, and Natsudaidain. At the same time, the chemical structure of M. citrifolia consists of 7-Hydroxy-Methoxycoumarin and Cirsiumaldehyde. A. vera and M. citrifolia crude extracts had lower inhibition than antibacterial control (Enrofloxacin) for P. aeruginosa. The lower bacteria inhibition was due to the low active materials (phenolic and flavonoid contents). So, the purification methods of crude extracts to obtain active materials with high antibacterial activity were needed. © 2022

关键词： Bacteria

Single-electron capture in 3-keV/u Ar8+-He collisions

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Physical Review A 2017年第4期95卷 042702-042702页

作者： R. T. Zhang X. L. Zhu X. Y. Li L. Liu S. F. Zhang W. T. Feng D. L. Guo Y. Gao D. M. Zhao J. G. Wang X. Ma Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China Data Center for High Energy Density Physics Institute of Applied Physics and Computational Mathematics Beijing 100088 China Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics University of Science and Technology of China Heifei 230026 China

The electron transfer mechanism was investigated for the single-electron-capture process in 3-keV/u Ar8+-He collisions with cold target recoil ion momentum spectroscopy. The different state-selective electron capture processes were identified for one 1s electron of He capture into 4s, 4p, 4d−4f, and 5s−5p states of Ar8+. We observed that 1s to 4s capture mainly happens at small transverse recoil ion momentum, while 1s to 4p capture mainly happens at large transverse recoil ion momentum. By comparing the measured projectile scattering angle distributions to the theoretical calculations, it is suggested that 1s to 4s and 1s to 4p state-selective capture processes are mainly caused by radial and rotational coupling effects, respectively, and the 4p±1 quantum states are preferred.

关键词： Scattering of atoms, molecules, clusters & ions

An Educational Perspective to Model and Controller Reduction of Dynamical Systems

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An Educational Perspective to Model and Controller Reduction...

Proceedings of the 46th IEEE Conference on Decision and Control, Pages 5052-5510

作者： Eduardo Gildin Robert H. Bishop Athanasios C. Antoulas Danny Sorensen The Institute for Computational Engineering and Sciences University of Texas Austin Austin TX USA ECE Department Rice University USA The Aerospace and Engineering Mechanics Department University of Texas Austin Austin TX USA Electrical and Computer Engineering Department Rice University Houston TX USA Computational and Applied Mathematics Rice University Houston TX USA

ISBN: (纸本)9781424414970

In this paper, and educational framework on model and controller reduction techniques arising in the study of dynamical systems is presented. The model reduction problem is posed in a projection framework, and some techniques are shown, such as balanced truncation, and moment matching by Krylov subspace, to obtain reduced-order models and controllers. The practical application of these reduced-order controllers are shown in a control laboratory setup, developed for teaching undergraduate control systems. The implementations were performed using the torsional disks apparatus controlled by LabVIEW.

关键词： Large-scale systems computational modeling Reduced order systems Laboratories Control systems Power system modeling computational fluid dynamics Circuit simulation Aerospace engineering Fluid flow control

Numerical Optimization applied to the Treatment of Aids in the Presence of Mutant HIV Virus

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IFAC Proceedings Volumes 2000年第3期33卷 85-89页

作者： J.A.M. Felippe De Souza Marco Antonio Leonel Caetano Takashi Yoneyama Department of Electromechanical Engineering Universidade da Beira Interior Covilhã Portugal Department of Statistics Computational and Applied Mathematics Universidade Estadual Paulista Rio Claro SP Brazil Electronics Engineering Division Instituto Tecnológico de Aeronáutica São José dos Campos SP Brazil

Here is presented an application of Optimal Control to a model describing the dynamics of an infection by HIV where mutant forms are present. It extends authours' previous results where mutant drug-resistant HIV virus were absent. The model adopted, proposed in (Nowak, et al , 1997) deals with the dynamics of viral concentrations. The control is the dose of an alternative drug exhibiting different activity from the primitive and mutant HIV viruses. The cost function is a weighted sum of the total viral load at a fixed time horizon and the accumulated side effects. Simulation results show that the optimal control scheme can achieve improved quality of the treatment.

关键词： Biomedical system Differential equations Nonlinear equations Numerical simulation Optimal control

Spatially dense stochastic epidemic models with infection-age dependent infectivity

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arXiv 2023年

作者： Pang, Guodong Pardoux, Étienne Department of Computational Applied Mathematics and Operations Research George R. Brown School of Engineering Rice University HoustonTX77005 United States Aix Marseille Univ CNRS I2M Marseille France

We study an individual-based stochastic spatial epidemic model where the number of locations and the number of individuals at each location both grow to infinity. Each individual is associated with a random infection-age dependent infectivity function. Individuals are infected through interactions across the locations with heterogeneous effects. The epidemic dynamics can be described using a time-space representation for the the total force of infection, the number of susceptible individuals, the number of infected individuals that are infected at each time and have been infected for a certain amount of time, as well as the number of recovered individuals. We prove a functional law of large numbers for these time-space processes, and in the limit, we obtain a set of time-space integral equations. We then derive the PDE models from the limiting time-space integral equations, in particular, the density (with respect to the infection age) of the time-age-space integral equation for the number of infected individuals tracking the age of infection satisfies a linear PDE in time and age with an integral boundary condition. These integral equation and PDE limits can be regarded as dynamics on graphon under certain conditions. Copyright © 2023, The Authors. All rights reserved.

关键词： Integral equations

Comparing the best reply strategy and mean field games: The stationary case

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arXiv 2019年

作者： BARKER, MATT DEGOND, PIERRE WOLFRAM, MARIE-THERESE Department of Mathematics Imperial College London LondonSW7 2AZ United Kingdom Grantham Institute Imperial College London LondonSW7 2AZ United Kingdom Department of Mathematics Imperial College London LondonSW7 2AZ United Kingdom University of Warwick Mathematics Institute Gibbet Hill Road CoventryCV47AL United Kingdom Radon Institute for Computational and Applied Mathematics Altenbergerstr. 69 Linz4040 Austria

Mean field games (MFGs) and the best reply strategy (BRS) are two methods of describing competitive optimisation of systems of interacting agents. The latter can be interpreted as an approximation of the respective MFG system, see [1, 3, 18]. In this paper we present a systematic analysis and comparison of the two approaches in the stationary case. We provide novel existence and uniqueness results for the stationary boundary value problems related to the MFG and BRS formulations, and we present an analytical and numerical comparison of the two paradigms in a variety of modelling situations. Copyright © 2019, The Authors. All rights reserved.

关键词： Fokker Planck equation

On the strong convergence of forward-backward splitting in reconstructing jointly sparse signals

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arXiv 2017年

作者： Dexter, Nick Tran, Hoang Webster, Clayton G. Department of Mathematics Simon Fraser University BurnabyBCV5A 1S6 Canada Department of Computational and Applied Mathematics Oak Ridge National Laboratory Oak RidgeTN37831-6164 United States Oden Institute for Computational Engineering & Sciences The University of Texas at Austin AustinTX78712 United States Behavioral Reinforcement Learning Lab Lirio LLC. KnoxvilleTN37923 United States

We consider the problem of reconstructing an infinite set of sparse, finite-dimensional vectors, that share a common sparsity pattern, from incomplete measurements. This is in contrast to the work [17], where the single vector signal can be infinite-dimensional, and [28], which extends the aforementioned work to the joint sparse recovery of finite number of infinite-dimensional vectors. In our case, to take account of the joint sparsity and promote the coupling of nonvanishing components, we employ a convex relaxation approach with mixed norm penalty 2,1. This paper discusses the computation of the solutions of linear inverse problems with such relaxation by a forward-backward splitting algorithm. However, since the solution matrix possesses infinitely many columns, the arguments of [17] no longer apply. As such, we establish new strong convergence results for the algorithm, in particular when the set of jointly sparse vectors is infinite. Copyright © 2017, The Authors. All rights reserved.

关键词： Relaxation processes