1,888 research outputs found
Anomalous dissipation and regularization in isotropic Gaussian turbulence
No full textIn this work we rigorously establish a number of properties of "turbulent" solutions to the stochastic transport and the stochastic continuity equations constructed by Le Jan and Raimond in [Ann. Probab. 30(2): 826-873, 2002]. The advecting velocity field, not necessarily incompressible, is Gaussian and white-in-time, space-homogeneous and isotropic, with -Hölder regularity in space, . We cover the full range of compressibility ratios giving spontaneous stochasticity of particle trajectories. For the stochastic transport equation, we prove that generic data experience anomalous dissipation of the mean energy, and study basic properties of the resulting anomalous dissipation measure. Moreover, we show that starting from such irregular data, the solution immediately gains regularity and enters into a fractional Sobolev space . The proof of the latter is obtained as a consequence of a new sharp regularity result for the degenerate parabolic PDE satisfied by the associated two-point self-correlation function, which is of independent interest. In the incompressible case, a Duchon-Robert-type formula for the anomalous dissipation measure is derived, making a precise connection between this self-regularizing effect and a limit on the flux of energy in the turbulent cascade. Finally, for the stochastic continuity equation, we prove that solutions starting from a Dirac delta initial condition undergo an average squared dispersion growing with respect to time as , rigorously establishing the analogue of Richardson's law of particle separations in fluid dynamics
The statistical geometry of material loops in turbulence
No full textMaterial elements - which are lines, surfaces, or volumes behaving as
passive, non-diffusive markers - provide an inherently geometric window into
the intricate dynamics of chaotic flows. Their stretching and folding dynamics
has immediate implications for mixing in the oceans or the atmosphere, as well
as the emergence of self-sustained dynamos in astrophysical settings. Here, we
uncover robust statistical properties of an ensemble of material loops in a
turbulent environment. Our approach combines high-resolution direct numerical
simulations of Navier-Stokes turbulence, stochastic models, and dynamical
systems techniques to reveal predictable, universal features of these complex
objects. We show that the loop curvature statistics become stationary through a
dynamical formation process of high-curvature folds, leading to distributions
with power-law tails whose exponents are determined by the large-deviations
statistics of finite-time Lyapunov exponents of the flow. This prediction
applies to advected material lines in a broad range of chaotic flows. To
complement this dynamical picture, we confirm our theory in the analytically
tractable Kraichnan model with an exact Fokker-Planck approach
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Mr. Theodore F. Bevan's Fifth expedition to British New Guinea : Preliminary presentation pamphlet (illustrated)
No full textLimited to 100 copies.; Author's presentation copy to the Editor of the Sydney Morning Herald.; Ferguson, no. 6989.; Also available in an electronic version via the Internet at: http://nla.gov.au/nla.aus-f6989; Ferguson copy signed by author
Theodore Deppe, 38th Annual ODU Literary Festival
No full textTheodore Deppe is the author of Beautiful Wheel, Orpheus on the Red Line, Cape Clear: New and Selected Poems, The Wanderer King, and Children of the Air. He has received a Pushcart Prize, two fellowships from the National Endowment for the Arts, and grants from the Massachusetts Cultural Commission and the Connecticut Commission on the Arts. His work has appeared in Poetry, Harper’s, Kenyon Review, Ploughshares, Poetry Ireland Review and elsewhere. He served as writer-in-residence at Phillips Academy in Massachusetts, the Poet\u27s House in Ireland, Westminster College in Utah, and the James Merrill House in Connecticut. He directs Stonecoast in Ireland and lives on the west coast of Ireland
Bizarre stromal cells in an endometrial polyp
No full textBizarre stromal cells have been reported in vulvovaginal polyps, as well as in nongynecologic sites, with caution not to mistake them for malignancy. Similar atypical stromal cells have only rarely been reported in the endometrium. We present a case found incidentally in a postmenopausal female, and review the literature.Peer reviewed
The laser inventor: memoirs of Theodore H. Maiman
No full textIn these engaging memoirs of a maverick, Theodore H. Maiman describes the life events leading to his invention of the laser in 1960. Maiman succeeded using his expertise in physics and engineering along with an ingenious and elegant design not anticipated by others. His pink ruby laser produced mankind’s first-ever coherent light and has provided transformational technology for commerce, industry, telecom, the Internet, medicine, and all the sciences. Maiman also chronicles the resistance from his employer and the ongoing intrigue by competing researchers in industry and academia seeking to diminish his contribution in inventing the first laser. This work will appeal to a wide readership, from physicists and engineers through science enthusiasts to general readers. The volume includes extensive photos and documentary materials related to Maiman’s life and accomplishments never before published. "No one beat Maiman to the laser. How important is the laser? How important are all lasers? That is how important we have to regard Maiman’s contribution.He and the laser changed all of our lives, everyone’s!" Dr. Nick Holonyak, Jr., Professor of Electrical and Computer Engineering and Physics, University of Illinois at Champaigne-Urbana, and inventor of the light-emitting diode (LED) and co-inventor of the transistor laser "More than five decades later, we can safely conclude that Theodore Maiman's groundbreaking discovery changed the world. Our modern life just as scientific research would be quite different without the laser." Dr. Ferenc Krausz, Director, Max Planck Institute for Quantum Optics, Garching, Germany, and Professor of Physics, Ludwig Maximilian University, Munich, and pioneer in attosecond lasers and attophysics "Maiman had the stroke of genius needed to take a different approach [from his competitors]. The sheer elegance and simplicity of his design belies the intellectual achievement it represents. If his invention seems obvious to some today, it was far from obvious in 1960." Jeff Hecht, authoritative science writer on the historical development of the laser, author of books on lasers and fiber optics
MANOVA modelling of a chiropractic longitudinal study using multiple imputation
No full textThe purpose of this report is to present the detailed statistical analysis of a randomised, placebo-controlled trial comparing two different treatment modalities to an intervention of no known benefit for people with acute or subacute thoracic spine pain.
The therapy arms consist of Spinal Manipulative Therapy (SMT) and Graston Technique (GT) and the placebo is a non-functional ultrasound. A placebo group was utilised because at present there are no proven treatments for non-specific thoracic pain. This trial is registered with the Australia and New Zealand Clinical Trials Registry. Ethics approval has been granted by Murdoch University Human Research and Ethics Committee, number 2007/274.
The aim of this three arm trial was to test the efficacy of SMT and GT as independent modalities compared to detuned ultrasound for the outcomes of pain and disability. The latter were measured using the Visual Analogue Scale (VAS) and a modified Oswestry Back Pain Disability Index. The study was conducted at the Murdoch University Chiropractic student clinic in Perth, Australia, and the protocol published in Crothers et al (2008).
In this report, Section 2 provides an initial exploratory analysis of the data, Section 3 outlines the statistical models used in the final analysis, Section 4 defines these models in mathematical terms, Section 5 discusses the management of missing values via multiple imputation and Section 6 presents the results of the statistical modelling and hypothesis tests. The clinical study will be published in full elsewhere
Theodore A. Burton (1935–2025)
No full textOutstanding researcher, author, and educator of differential equations, Theodore A. Burton passed away on January 5, 2025, in his 90th year
Dr. Theodore Kratt
No full textThis is an individual portrait of Dr. Theodore Kratt, the author of the official college song McMinnville College: To You We\u27re Always True, penned in 1917.https://digitalcommons.linfield.edu/lca_photos/1164/thumbnail.jp
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