Models of Vortices and Spirals in White Dwarf's Accretion Binaries

The main aim in the current survey is to suggest models of the development of structures, such as vortices and spirals, in accretion white dwarf's binaries. Numerical methods and simulations are applied on the bases of hydrodynamic analytical considerations. It is suggested in the theoretical model the perturbation's parameters of the accretion flow, which are caused by the influences of the tidal wave over the flux of accretion matter around the secondary star. The results of numerical code application on the disturbed flow reveal an appearing of structure with spiral shape due to the tidal interaction in the close binaries. Our further simulations give the solution, which expresses the formation of vortical configurations in the accretion disc's zone. The evolution of vortices in areas of the flow's interaction is explored using single vortex and composite vortex models. Gas in the disc matter is considered to be compressible and non-ideal. The longevity of all these structures is different and each depends on the time period of the rotation, density and velocity of the accretion matter.Comment: 4 page

Visualizing Creative Destruction

We introduce a series of methods for visualizing the dynamics of firmsize as indicative of the way the creation of new economic entitiesdestroy the existing order in the manner first sketched bySchumpeter (1938). We examine firm size distributions for every yearfrom 1955 to 1994 for the top 100 firms listed in the Fortune 500. Weshow that although rank-size distributions from this data areremarkably stable, this masks a much more detailed microdynamicswhere firms are changing their size and rank in the prevailing orderquite rapidly. These provide the signatures of creation anddestruction and to visualize their form, we introduce the idea of halflives, rank clocks and distance statistics which reveal a cornucopia ofdynamic behaviors. We first examine changes in firm size measuredby revenue earnings and then we contrast this with profits perearnings data which reveals another picture of these processes ofcreation and destruction. We introduce a series of methods for visualizing the dynamics of firmsize as indicative of the way the creation of new economic entitiesdestroy the existing order in the manner first sketched bySchumpeter (1938). We examine firm size distributions for every yearfrom 1955 to 1994 for the top 100 firms listed in the Fortune 500. Weshow that although rank-size distributions from this data areremarkably stable, this masks a much more detailed microdynamicswhere firms are changing their size and rank in the prevailing orderquite rapidly. These provide the signatures of creation anddestruction and to visualize their form, we introduce the idea of halflives, rank clocks and distance statistics which reveal a cornucopia ofdynamic behaviors. We first examine changes in firm size measuredby revenue earnings and then we contrast this with profits perearnings data which reveals another picture of these processes ofcreation and destruction

Visualizing Spacetime Curvature via Frame-Drag Vortexes and Tidal Tendexes I. General Theory and Weak-Gravity Applications

When one splits spacetime into space plus time, the Weyl curvature tensor (vacuum Riemann tensor) gets split into two spatial, symmetric, and trace-free (STF) tensors: (i) the Weyl tensor's so-called "electric" part or tidal field, and (ii) the Weyl tensor's so-called "magnetic" part or frame-drag field. Being STF, the tidal field and frame-drag field each have three orthogonal eigenvector fields which can be depicted by their integral curves. We call the integral curves of the tidal field's eigenvectors tendex lines, we call each tendex line's eigenvalue its tendicity, and we give the name tendex to a collection of tendex lines with large tendicity. The analogous quantities for the frame-drag field are vortex lines, their vorticities, and vortexes. We build up physical intuition into these concepts by applying them to a variety of weak-gravity phenomena: a spinning, gravitating point particle, two such particles side by side, a plane gravitational wave, a point particle with a dynamical current-quadrupole moment or dynamical mass-quadrupole moment, and a slow-motion binary system made of nonspinning point particles. [Abstract is abbreviated; full abstract also mentions additional results.]Comment: 25 pages, 20 figures, matches the published versio

The two regimes of the cosmic sSFR evolution are due to spheroids and discs

This paper aims at explaining the two phases in the observed specific star formation rate (sSFR), namely the high (>3/Gyr) values at z>2 and the smooth decrease since z=2. In order to do this, we compare to observations the specific star formation rate evolution predicted by well calibrated models of chemical evolution for elliptical and spiral galaxies, using the additional constraints on the mean stellar ages of these galaxies (at a given mass). We can conclude that the two phases of the sSFR evolution across cosmic time are due to different populations of galaxies. At z>2 the contribution comes from spheroids: the progenitors of present-day massive ellipticals (which feature the highest sSFR) as well as halos and bulges in spirals (which contribute with average and lower-than-average sSFR). In each single galaxy the sSFR decreases rapidly and the star formation stops in <1 Gyr. However the combination of different generations of ellipticals in formation might result in an apparent lack of strong evolution of the sSFR (averaged over a population) at high redshift. The z<2 decrease is due to the slow evolution of the gas fraction in discs, modulated by the gas accretion history and regulated by the Schmidt law. The Milky Way makes no exception to this behaviour.Comment: 8 pages, 5 figures, MNRAS accepte

Visualizing Shakespeare: Iconography and Interpretation in the Works of Salvador Dalí

Although William Shakespeare’s 16th century classical literature is rarely contextualized with the eccentricities of 20th century artist Salvador Dali, Shakespeare’s myriad of works have withstood the test of time and continue to be celebrated and reinterpreted by the likes of performers, scholars, and artists alike. Along with full-text illustrations of well-known plays, such as Macbeth (1946) and As You Like It (1953), Dali returned to the Shakespearean motif with his two series of dry-point engravings (Much Ado About Shakespeare and Shakespeare II) in 1968 and 1971. The series combine to formulate 31 depictions where Dali interprets Shakespeare’s text in a single image with classics like Romeo & Juliet as well as some of Shakespeare’s more obscure plays, such as Troilus and Cressida and Timon of Athens. Gettysburg College owns several of these prints, housed in the library’s Special Collections. Troilus and Cressida and Timon of Athens were on display in Schmucker Art Gallery as part of the Method and Meaning exhibit in the fall of 2014. Shakespeare’s plays are an eclectic repertoire of iconic characters such as Prince Hamlet and Othello as well as timeless themes (both comic and tragic) that easily lend themselves to an extraordinary diverse range of illustrations; from the 18th century historical narratives of Francis Hayman, 19th century whimsical paintings of William Blake, Victorian renditions of John Everett Millais, and then eventually leading to the 20th expressive freedom of Dali. Salvador Dali’s representations, like his predecessors, aim to capture the essence of each Shakespeare play using specific iconographic elements in order to create a visual narration, bringing together the interpretations of the author, artist, and the viewer