1,759 research outputs found

    Saccate pollen grains from the Lower Cretaceous of the Great Artesian Basin, Australia

    Get PDF

    Baudelaire’s “Le Jet d’eau”: Verbal-Visual Inquiry and the Illustrated Book

    Get PDF
    A single text illustrated by several artists presents a unique opportunity for image-text inquiry. This is indeed the case with the illustrators of Baudelaire’s “Le jet d’eau” from his celebrated Fleurs du mal. As each illustrator renders the text into images that represent a unique “reading” of it, our understanding of the poetic gesture is frequently enriched by the graphic gesture. Novel critical points of view which may generate a substantial rethinking of the aesthetic contours of the textual entity thus come into focus. The traditional function of illustration as shedding light onto the word, or of actually extending its meaning to transcend habitual mimetic approaches, evolves with the advent of Modernity as modes of representation espouse fresh contours. “Le jet d’eau” has had a prolific career in the twentieth-century livre d’artiste. Offering a rich terrain of interpretative possibilities, this poem has enticed an array of artists to picture it often unexpected ways. Our point of departure will consider both poetic and graphic universes as écritures whose intersections propose uncommon thresholds beyond which are poised new ideas. This notion is central to our concerns. Similarly, the dynamics of IMAGinING ideas, the interfacing of verbal and visual planes, and the move from representation to abstraction are germane to this investigation. Thus, this discussion of how twentieth-century artists have represented this nineteenth-century text will at once re-frame and re-figure the intrinsic value of illustration as interpretation.L’illustration d’un seul texte par plusieurs artistes présente une occasion remarquable d’étudier les rapports texte/image. C’est ce que nous offre l’étude des illustrateurs du poème de Baudelaire, « Le jet d’eau », extrait des Fleurs du mal. Chaque illustrateur apporte sa « lecture » particulière du poème, et notre compréhension de l’œuvre s’en trouve modifiée. Des éléments critiques nouveaux nous apparaissent et nous conduisent à repenser les contours esthétiques du document. La fonction traditionnelle de l’illustration qui consiste à éclairer le texte, ou à en élargir la portée pour aller au-delà des approches mimétiques, a évolué avec l’avènement de la Modernité. « Le jet d’eau » a inspiré de nombreux livres d’artistes. En raison de ses multiples niveaux d’interprétation, le poème a suscité des illustrations très variées et parfois inattendues. Nous postulerons que les univers poétique et graphique sont chacun des écritures à l’intersection desquelles de nouvelles idées peuvent prendre leur essor. C’est ce qui nous semble central. De même, la manière d’IMAGinER les idées, les ponts entre le visuel et le verbal, et le passage de la représentation à l’abstraction accompagnent notre étude. Ainsi, la façon dont les artistes du vingtième siècle ont représenté le poète du dix-neuvième siècle nous permet de re-cadrer et re-figurer la valeur intrinsèque de l’illustration comme représentation

    Gravitational wave emission from a magnetically deformed non-barotropic neutron star

    Full text link
    A strong candidate for a source of gravitational waves is a highly magnetised, rapidly rotating neutron star (magnetar) deformed by internal magnetic stresses. We calculate the mass quadrupole moment by perturbing a zeroth-order hydrostatic equilibrium by an axisymmetric magnetic field with a \emph{linked poloidal-toroidal structure}. In this work, we do \emph{not} require the model star to obey a barotropic equation of state (as a realistic neutron star is not barotropic), allowing us to explore the hydromagnetic equilibria with fewer constraints. We derive the relation between the ratio of poloidal-to-total field energy Λ\Lambda and ellipticity ϵ\epsilon and briefly compare our results to those obtained using the barotropic assumption. Then, we present some examples of how our results can be applied to astrophysical contexts. First, we show how our formulae, in conjunction with current gravitational wave (non-)detections of the Crab pulsar and the Cassiopeia A central compact object (Cas A CCO), can be used to constrain the strength of the internal toroidal fields of those objects. We find that, for the Crab pulsar (whose canonical equatorial dipole field strength, inferred from spin down, is 4×1084\times 10^8 T) to emit detectable gravitational radiation, the neutron star must have a strong toroidal field component, with maximum internal toroidal field strength Btm=7×1012B_{\mathrm{tm}}=7\times 10^{12} T; for gravitational waves to be detected from the Cas A CCO at 300 Hz, Btm1013B_{\mathrm{tm}}\sim 10^{13} T, whereas detection at 100 Hz would require Btm1014B_{\mathrm{tm}}\sim 10^{14} T. Using our results, we also show how the gravitational wave signal emitted by a magnetar immediately after its birth (assuming it is born rapidly rotating, with Λ0.2\Lambda\lesssim 0.2) makes such a newborn magnetar a stronger candidate for gravitational wave detection than, for example, an SGR giant flare.Comment: 15 pages, 8 figures, 2 table

    Synchrotron x-ray-diffraction study of the structure and growth of Xe films adsorbed on the Ag(111) surface

    Get PDF
    URL:http://link.aps.org/doi/10.1103/PhysRevB.59.15464 DOI:10.1103/PhysRevB.59.15464Synchrotron x-ray scattering has been used to investigate the structure and growth of perhaps the simplest of all films: xenon physisorbed on the Ag(111) surface. High-resolution x-ray scans of the in-plane structure and lower-resolution scans (specular and nonspecular) of the out-of-plane order were performed. The Xe films were prepared under both quasiequilibrium and kinetic growth conditions, and have fewer structural defects than those investigated previously by others on graphite substrates. Under quasiequilibrium conditions, the bulk Xe-Xe spacing is reached at monolayer completion, and the monolayer and bilayer lattice constants at coexistence are inferred equal to within 0.005 Å, consistent with theoretical calculations. The Xe/vacuum interface profile for a complete monolayer and bilayer grown at quasiequilibrium is found to be sharper than for kinetically grown films. At coverages above two layers, diffraction scans along the Xe(01l) rod for quasiequilibrated films are consistent with the presence of two domains having predominantly an ABC stacking sequence and rotated 60° with respect to each other about the surface normal. Annealing of these films alters neither the population of the two domains nor the fraction of ABA stacking faults. The thickest film grown under quasiequilibrium conditions exceeds 220 Å (resolution limited). Under kinetic growth conditions, x-ray intensity oscillations at the Xe anti-Bragg position of the specular rod are observed as a function of time, indicating nearly layer-by-layer growth. Up to four complete oscillations corresponding to a film of eight layers have been observed before the intensity is damped out; the number of oscillations is found to depend on the substrate temperature, the growth rate, and the quality of the Ag(111) substrate. The specular reflectivity from kinetically grown films at nominal coverages of three and four layers has been analyzed using a Gaussian model which gives a film thickness standard deviation of 0.5 and 1.0 layers, respectively. Diffraction scans along the Xe(01l) rod of these films indicate a larger fraction of ABA stacking faults than found for thicker films. These results demonstrate the difficulty of kinetically growing Xe films thicker than two layers which have an ideal slab geometry.This work was partially supported by U.S. National Science Foundation Grant Nos. DMR-8704938, DMR-9011069, and DMR-9314235 and the U.S. Department of Energy Grant No. DE-FG02-85ER45183 of the MATRIX Participating Research Team

    An algebraic approach to problems with polynomial Hamiltonians on Euclidean spaces

    Full text link
    Explicit expressions are given for the actions and radial matrix elements of basic radial observables on multi-dimensional spaces in a continuous sequence of orthonormal bases for unitary SU(1,1) irreps. Explicit expressions are also given for SO(N)-reduced matrix elements of basic orbital observables. These developments make it possible to determine the matrix elements of polynomial and a other Hamiltonians analytically, to within SO(N) Clebsch-Gordan coefficients, and to select an optimal basis for a particular problem such that the expansion of eigenfunctions is most rapidly convergent.Comment: 19 pages, 8 figure

    Elasticity of Semiflexible Biopolymer Networks

    Full text link
    We develop a model for gels and entangled solutions of semiflexible biopolymers such as F-actin. Such networks play a crucial structural role in the cytoskeleton of cells. We show that the rheologic properties of these networks can result from nonclassical rubber elasticity. This model can explain a number of elastic properties of such networks {\em in vitro}, including the concentration dependence of the storage modulus and yield strain.Comment: Uses RevTeX, full postscript with figures available at http://www.umich.edu/~fcm/preprints/agel/agel.htm

    Gravitational waves from single neutron stars: an advanced detector era survey

    Full text link
    With the doors beginning to swing open on the new gravitational wave astronomy, this review provides an up-to-date survey of the most important physical mechanisms that could lead to emission of potentially detectable gravitational radiation from isolated and accreting neutron stars. In particular we discuss the gravitational wave-driven instability and asteroseismology formalism of the f- and r-modes, the different ways that a neutron star could form and sustain a non-axisymmetric quadrupolar "mountain" deformation, the excitation of oscillations during magnetar flares and the possible gravitational wave signature of pulsar glitches. We focus on progress made in the recent years in each topic, make a fresh assessment of the gravitational wave detectability of each mechanism and, finally, highlight key problems and desiderata for future work.Comment: 39 pages, 12 figures, 2 tables. Chapter of the book "Physics and Astrophysics of Neutron Stars", NewCompStar COST Action 1304. Minor corrections to match published versio

    Does Weight Loss Cause the Exercise-induced Increase in Plasma High Density Lipoproteins?

    Get PDF
    Studies showing an increase in plasma concentration of high density lipoprotein cholesterol (HDL-C) with moderate exercise have usually rejected the role of body weight change in the HDL-C raising process, ostensibly because the amount of weight lost has been negligible. To investigate HDL-C changes more thoroughly, we followed initially sedentary middle-aged men randomly assigned to either a moderate running (N=36) or a sedentary control (N=28) group for one year. Among runners, one-year changes in plasma HDL-C concentrations correlated strongly with their body weight changes (r = -0.53, P \u3c 0.001). Curve-fitting procedures and regression analysis suggested that processes associated with weight change produce much of the plasma HDL-C changes induced by moderate exercise and that changes in HDL-C concentration predominantly reflect changes in the reputedly anti-atherogenic HDL2 sub-component. Further, the interaction between weight change and plasma HDL-C concentration was significantly different (
    corecore