417 research outputs found
When to interfere with dark matter? The impact of wave dynamics on statistics
Get PDFGough A, Uhlemann C. When to interfere with dark matter? The impact of wave dynamics on statistics. The Open Journal of Astrophysics. 2024;7.Ultralight candidates for dark matter can present wavelike features on astrophysical scales. Full wave based simulations of such candidates are currently limited to box sizes of 1–10 Mpc/h on a side, limiting our understanding of the impact of wave dynamics on the scale of the cosmic web. We present a statistical analysis of density fields produced by perturbative forward models in boxes of 128 Mpc/h side length. Our wave-based perturbation theory maintains interference on all scales, and is compared to fluid dynamics of Lagrangian perturbation theory. The impact of suppressed power in the initial conditions and interference effects caused by wave dynamics can then be disentangled. We find that changing the initial conditions captures most of the change in one-point statistics such as the skewness of the density field. However, different environments of the cosmic web, quantified by critical points of the smoothed density, appear to be more sensitive to interference effects sourced by the quantum potential. This suggests that certain large-scale summary statistics may need additional care when studying cosmologies with wavelike dark matter
Digestive Enzymes of Human and Nonhuman Primates
No full textAll living organisms need to consume nutrients to grow, survive, and reproduce, making the successful acquisition of food resources a powerful selective pressure. However, acquiring food is only part of the challenge. While all animals spend much of their daily activity budget hunting, searching for, or otherwise procuring food, a large part of what is involved in overall nutrition occurs once the meal has been swallowed. Most nutritional components are too complex for immediate use and must be broken down into simpler compounds, which can then be absorbed by the body. This process, digestion, is catalyzed by enzymes that are either endogenous or produced by the host's microbial population. Research shows that the nutritional value of food is partially constrained by the digestive abilities of the microbial community present in the host's gut and that these microbes rapidly adapt to changes in diet and other environmental pressures. An accumulating body of evidence suggests that endogenously produced digestive enzymes also have been, and still are, common targets of natural selection, further cementing their crucial role in an organism's digestive system.Peer reviewe
Anna Cora Mowatt as Rosalind
No full textEngraving of Anna Cora Mowatt as Rosalind in Shakespeare's As You Like It. Anna Cora Mowatt Ritchie was an author, playwright, public reader, and actres
Beyond single-stream with the Schrödinger method
No full textUhlemann C, Kopp M. Beyond single-stream with the Schrödinger method. Proceedings of the International Astronomical Union. 2014;11(S308):115-118.We investigate large scale structure formation of collisionless dark matter in the phase space description based on the Vlasov-Poisson equation. We present the Schrödinger method, originally proposed by \cite{WK93} as numerical technique based on the Schrödinger Poisson equation, as an analytical tool which is superior to the common standard pressureless fluid model. Whereas the dust model fails and develops singularities at shell crossing the Schrödinger method encompasses multi-streaming and even virialization
Anna Cora Mowatt as Rosalind
No full textEngraving of Anna Cora Mowatt as Rosalind in Shakespeare's As You Like It. 'Tis he; slink by, & note him.' Act 5, Sc.2. Anna Cora Mowatt Ritchie was an author, playwright, public reader, and actres
Cora Lynn School District No. 2012
No full textPhotograph - Alice B. Donahue's first school, Cora Lynn School, Red Willow, Alberta. The Junior Room had 40 pupils and George Carter (later president of NAIT) is on far left wearing a white shir
Coarse-grained cosmological perturbation theory: Stirring up the dust model
No full textUhlemann C, Kopp M. Coarse-grained cosmological perturbation theory: Stirring up the dust model. Physical Review D. 2015;91(8): 084010.We study the effect of coarse graining the dynamics of a pressureless self-gravitating fluid (coarse-grained dust) in the context of cosmological perturbation theory, in both the Eulerian and Lagrangian frameworks. We obtain recursion relations for the Eulerian perturbation kernels of the coarse-grained dust model by relating them to those of the standard pressureless fluid model. The effect of the coarse graining is illustrated by means of power and cross spectra for the density and velocity, which are computed up to one-loop order. In particular, the large-scale vorticity power spectrum that arises naturally from a mass-weighted velocity is derived from first principles. We find qualitatively good agreement for the magnitude, shape, and spectral index of the vorticity power spectrum with recent measurements from -body simulations and results from the effective field theory of large-scale structure. To lay the ground for applications in the context of Lagrangian perturbation theory, we finally describe how the kernels obtained in Eulerian space can be mapped to Lagrangian ones
Numerical complexity of the joint nulled weak-lensing probability distribution function
No full textBarthelemy A, Bernardeau F, Codis S, Uhlemann C. Numerical complexity of the joint nulled weak-lensing probability distribution function. Physical Review D. 2022;105(4): 043537.In the context of tomographic cosmic shear surveys, there exists a nulling transformation of weak lensing observations (also called BNT transform) that allows us to simplify the correlation structure of tomographic cosmic shear observations, as well as to build observables that depend only on a localized range of redshifts and thus independent from the low-redshift/small-scale modes. This procedure renders possible accurate, and from-first-principles, predictions of the convergence and aperture mass one-point distributions (PDF). We here explore other consequences of this transformation on the (reduced) numerical complexity of the estimation of the joint PDF between nulled bins and demonstrate how to use these results to make theoretical prediction
Making (dark matter) waves: Untangling wave interference for multi-streaming dark matter
No full textGough A, Uhlemann C. Making (dark matter) waves: Untangling wave interference for multi-streaming dark matter. The Open Journal of Astrophysics. 2022;5(1).The classical dynamics of collisionless cold dark matter, commonly described by fluid variables or a phase-space distribution, can be captured in a single semiclassical wavefunction. We illustrate how classical multi-streaming creates wave interference in a toy model corresponding to the dynamics of the Zel’dovich approximation and link it to diffraction optics. Wave interference dresses the classical skeleton of cold dark matter with universal features akin to the physical imprints of wavelike (or fuzzy) dark matter. We untangle this wave interference to obtain single-stream wavefunctions corresponding to the classical fluid streams, by writing the wavefunction in an integral form. Our wave decomposition captures the full phase-space information and isolates the multi-stream phenomena related to vorticity and velocity dispersion. We link the wave interference features of our system to the standard forms of diffraction catastrophe integrals, which produce bright caustics in optical fields analogous to the cold dark matter density field. Our two complementary descriptions of dark matter wave-fields present rich universal features that can unlock new ways of modelling and probing wavelike dark matter on the scales of the cosmic web
MATIZ INTENSA DE CORA CORALINA
Get PDFThis study establishes relationships between poetic approaches and techniques of artistic interventions carried out at the Casa de Cora Coralina Museum, on the banks of the Vermelho River, located in the City of Goiás. The triangle of life, air, land and water, central representatives of Cora Coralina\u27s poetry, in portraits of the local color of ruddy hues. From a phenomenological approach, the text traveled through the geographical spaces presented in the author\u27s lyrics, verses and poetry, as poetic paths of trajectory in nuclei. In the elements of his house of ecologically correct creators, cultural technologies cross the environment, which unveiling meanings of poetics, which flow in nozzles and nozzles of Goiás.Este estudio establece relaciones entre los enfoques poéticos y las técnicas de las intervenciones artísticas realizadas en el Museo Casa de Cora Coralina, a orillas del río Vermelho, ubicado en la ciudad de Goiás. El triángulo de la vida, aire, tierra y agua, representantes centrales de la poesía de Cora Coralina, en retratos del color local de tonos rojizos. Desde un enfoque fenomenológico, el texto recorrió los espacios geográficos presentados en las letras, versos y poesías del autor, como caminos poéticos de trayectoria en núcleos. En los elementos de su casa de creadores ecológicamente correctos, tecnologías culturales atraviesan el ambiente, que develando significados de poéticas, que fluyen en toberas y toberas de Goiás.Este estudo propõe estabelecer relações entre abordagens poéticas e técnicas de intervenções artísticas realizadas no Museu Casa de Cora Coralina, às margens do rio Vermelho, situado na Cidade de Goiás. O triângulo da vida, ar, terra e água, representam elementos centrais da poesia de Cora Coralina, em retratos da cor local de matizes coradas. De abordagem fenomenológica, o texto percorre espaços geográficos apresentados em letras, versos e poesias da autora, como caminhos poéticos de trajetos em cores. Nos elementos tonalizantes de sua casa, artefatos tecnológicos culturais atravessam o ambiente, desvelando sentidos da poética de autoria de Cora Coralina, que escoam em bicos e ecoam nos becos da Cidade de Goiás
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