Multi-patch discontinuous Galerkin isogeometric analysis for wave propagation: explicit time-stepping and efficient mass matrix inversion

We present a class of spline finite element methods for time-domain wave propagation which are particularly amenable to explicit time-stepping. The proposed methods utilize a discontinuous Galerkin discretization to enforce continuity of the solution field across geometric patches in a multi-patch setting, which yields a mass matrix with convenient block diagonal structure. Over each patch, we show how to accurately and efficiently invert mass matrices in the presence of curved geometries by using a weight-adjusted approximation of the mass matrix inverse. This approximation restores a tensor product structure while retaining provable high order accuracy and semi-discrete energy stability. We also estimate the maximum stable timestep for spline-based finite elements and show that the use of spline spaces result in less stringent CFL restrictions than equivalent piecewise continuous or discontinuous finite element spaces. Finally, we explore the use of optimal knot vectors based on L2 n-widths. We show how the use of optimal knot vectors can improve both approximation properties and the maximum stable timestep, and present a simple heuristic method for approximating optimal knot positions. Numerical experiments confirm the accuracy and stability of the proposed methods

Cosmopolitanism, civil disobedience and the global legacy of Martin Luther King

Through the 19th century, the motor of China’s geopolitical change shifted from Eurasia to its southern coast. The impact of the West on China, while resulting in disastrous territorial concessions, also gave rise to a Southern Cosmopolitanism, with Guangdong native, Kang Youwei, becoming a cutting edge figure. 120 years ago, Kang led the first major drive to modernize China in the ill-fated Hundred Days Reform. Three years earlier, in 1895, he organized Gongche Shangshu, the first Chinese “student movement” to petition the royal court for political reform. For many, this activist lineage’s latest manifestation was the Umbrella Movement, Hong Kong’s 79-day Occupy demonstration for universal suffrage in 2014. Following the Arab Spring and a worldwide economic justice movement spearheaded by Occupy Wall Street, the Umbrella Movement originated as a civil disobedience campaign called “Occupy Central with Love and Peace.” One crucial document that inspired Benny Tai, law professor and conceiver of Occupy Central, is Martin Luther King’s “Letter from Birmingham Jail” (1963). The Occupy campaign used the “Birmingham” essay as the foundation for an outstanding civic education initiative drawing upon a global legacy evolved from Thoreau and Gandhi. Evans Chan, New York-based film critic and director of “Raise the Umbrellas” (2016/2018) and acclaimed documentaries about Kang Youwei, explores this early stage of the Umbrella Movement to survey the continuing relevance of King’s legacy in the US, Hong Kong, and the world today. Speaker Born in Guangdong and grew up in Macau and Hong Kong, Evans Chan is an internationally renowned critic, librettist, playwright, and filmmaker. He received his Master’s degree from the New School for Social Research in New York and PhD in Screen Culture at Northwestern University, USA. Currently based in New York, Chan is one of Hong Kong’s leading independent filmmakers. His award-winning films have been shown at the Berlin, Rotterdam, London, Moscow, Vancouver, San Francisco and Taiwan film festivals, among others. In his dramatic and documentary films Chan explores the challenges confronting Hong Kong before and after its return to Chinese rule in 1997. To Liv(e) (1991) was listed as one of the 100 Greatest Hong Kong Films by Time Out Magazine in Hong Kong. Raise the Umbrellas (2016–2018) documents the 79-day massive democratic protests known as the Umbrella Movement in 2014. As a playwright, Chan developed in 2015 his award-winning film Datong: The Great Society (2011) into the libretto as Datong: The Chinese Utopia, which was presented by the Hong Kong Arts Festival and staged in London in 2017. Chan is also a writer whose work has appeared in many Chinese and English publications. His English-language play, adapted from Chinese writer Eileen Chang’s novel Naked Earth, was staged at New York’s Bank Street Theater. Filmography: To Liv(e) (1992), Crossings (1994), Journey to Beijing (1998), Adeus Macau (2000), The Map of Sex and Love (2001), Bauhinia (2002), The Life and Times of Wu Zhongxian (2002), Sorceress of the New Piano: The Artistry of Margaret Leng Tan (2004), Makrokosmos I & II (2004), The Maverick Piano (2007), Datong: The Great Society (2011), Two or Three Things About Kang Youwei (2012), The Rose of the Name: Writing Hong Kong (2014), Raise the Umbrellas (2016), Death in Montmartre (2017). www.evanschan.com Discussant Leo Ou-fan Lee is currently the Sin Wai Kin Professor of Chinese Culture at the Chinese University of Hong Kong. He received his Ph. D. degree from Harvard in 1970 and has taught at Harvard, UCLA, Chicago, Indiana, and Princeton Universities in the United States, as well as the University of Hong Kong and the Hong Kong University of Science and Technology as visiting professor. His scholarly publications in English include: Shanghai Modern: The Flowering of a New Form of Urban Culture, 1930-1945 (Harvard University Press, 1999), Voices from the Iron House: A Study of Lu Xun (Indiana University Press, 1987), The Romantic Generation of Modern Chinese Writers (Harvard, 1973), City between Worlds: My Hong Kong (Harvard University Press, 2008), and Musings: Reading Hong Kong, China and the World (Hong Kong: Muse Books, 2011). In Hong Kong, he is known as both a scholar and cultural critic and has published more than 20 books in Chinese across a wide spectrum of subjects: literature, Hong Kong culture, film, classic music, and architecture. Moderator Stephen Ching-kiu Chan is Professor of Cultural Studies at Lingnan University. He is the current Chair of the international Association for Cultural Studies, and the Chair of Board of Directors, The House of Hong Kong Literature. HKAC Website: https://www.hkac.org.hk/calendar_detail/?u=VEfBtuw6w_U&lang=e

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Texas Citrus, Citrus, Shipments, Market Areas, Crop Production/Industries, Marketing,

Texas Fresh Citrus Shipments by Containers 1972-73

Texas, Citrus, Shipments, Containers, Crop Production/Industries, Food Consumption/Nutrition/Food Safety, Productivity Analysis,

High intensity x-ray diffraction in transmission mode employing an analog of Poisson's spot

Poisson’s spot is a diffraction phenomenon producing an intensity maximum at the center of the geometric shadow of circular opaque objects. In an analog of the Poisson spot experiment, we show that a tubular cone of x-rays incident upon a crystalline sample produces diffraction spots or foci, corresponding to Bragg maxima within a transmission shadow. We discuss the beam geometry and the intensity gain recorded at the foci in transmission mode. We describe the geometric growth and decay of the foci over a linear axis with the aid of a movie sequence synchronized with the plotting of a diffractogram. The mean signal of a small central area in each successive camera image provides the intensity data for the diffractogram

MicroRNA-762 is upregulated in human corneal epithelial cells in response to tear fluid and Pseudomonas aeruginosa antigens and negatively regulates the expression of host defense genes encoding RNase7 and ST2.

Mucosal surfaces regulate defenses against infection and excessive inflammation. We previously showed that human tears upregulated epithelial expression of genes encoding RNase7 and ST2, which inhibited Pseudomonas aeruginosa invasion of human corneal epithelial cells. Here, microRNA microarrays were used to show that a combination of tear fluid exposure (16 h) then P. aeruginosa antigens (3 h) upregulated miR-762 and miR-1207, and down-regulated miR-92 and let-7b (all > 2-fold) in human corneal epithelial cells compared to P. aeruginosa antigens alone. RT-PCR confirmed miR-762 upregulation ∼ 3-fold in tear-antigen exposed cells. Without tears or antigens, an antagomir reduced miR-762 expression relative to scrambled controls by ∼50%, increased expression of genes encoding RNase7 (∼80 %), ST2 (∼58%) and Rab5a (∼75%), without affecting P. aeruginosa internalization. However, P. aeruginosa invasion was increased > 3-fold by a miR-762 mimic which reduced RNase7 and ST2 gene expression. Tear fluid alone also induced miR-762 expression ∼ 4-fold, which was reduced by the miR-762 antagomir. Combination of tear fluid and miR-762 antagomir increased RNase7 and ST2 gene expression. These data show that mucosal fluids, such as tears, can modulate epithelial microRNA expression to regulate innate defense genes, and that miR-762 negatively regulates RNase7, ST2 and Rab5a genes. Since RNase7 and ST2 inhibit P. aeruginosa internalization, and are upregulated by tear fluid, other tear-induced mechanisms must counteract inhibitory effects of miR-762 to regulate resistance to bacteria. These data also suggest a complex relationship between tear induction of miR-762, its modulation of innate defense genes, and P. aeruginosa internalization

Stringy Symmetries and Their High-energy Limits

We derive stringy symmetries with conserved charges of arbitrarily high spins from the decoupling of two types of zero-norm states in the old covariant first quantized (OCFQ) spectrum of open bosonic string. These symmetries are valid to all energy and all loop orders in string perturbation theory. The high-energy limit of these stringy symmetries can then be used to fix the proportionality constants between scattering amplitudes of different string states algebraically without referring to Gross and Mende's saddle point calculation of high-energy string-loop amplitudes. These proportionality constants are, as conjectured by Gross, independent of the scattering angle and the order of string perturbation theory. However, we also discover some new nonzero components of high-energy amplitudes not found previously by Gross and Manes. These components are essential to preserve massive gauge invariances or decouple massive zero-norm states of string theory. A set of massive scattering amplitudes and their high energy limit are calculated explicitly to justify our results.Comment: 10 pages. A corrected version of hep-th/0303012. Final version to appear in Phys. Lett.

Arc Second Alignment of International X-Ray Observatory Mirror Segments in a Fixed Structure

The optics for the International X-Ray Observatory (IXO) require alignment and integration of about fourteen thousand thin mirror segments to achieve the mission goal of 3.0 square meters of effective area at 1.25 keV with an angular resolution of five arc seconds. These mirror segments are 0.4mm thick, and 200 to 400mm in size, which makes it hard not to impart distortion at the subarc second level. This paper outlines the precise alignment, verification testing, and permanent bonding techniques developed at NASA's Goddard Space Flight Center (GSFC). These techniques are used to overcome the challenge of transferring thin mirror segments from a temporary mount to a fixed structure with arc second alignment and minimal figure distortion. Recent advances in technology development in addition to the automation of several processes have produced significant results. This paper will highlight the recent advances in alignment, testing, and permanent bonding techniques as well as the results they have produced

Zero-norm states and High-energy Symmetries of String Theory

We derive stringy Ward identities from the decoupling of two types of zero-norm states in the old covariant first quantized (OCFQ) spectrum of open bosonic string. These Ward identities are valid to all energy and all loop orders in string perturbation theory. The high-energy limit of these stringy Ward identities can then be used to fix the proportionality constants between scattering amplitudes of different string states algebraically without referring to Gross and Mende's saddle point calculation of high-energy string-loop amplitudes. As examples, all Ward identities for the mass level 4 and 6 are derived, their high-energy limits are calculated and the proportionality constants between scattering amplitudes of different string states are determined. In addition to those identified before, we discover some new nonzero components of high-energy amplitudes not found previously by Gross and Manes. These components are essential to preserve massive gauge invariances or decouple massive zero-norm states of string theory. A set of massive scattering amplitudes and their high energy limits are calculated explicitly for each mass level to justify our results