11,947 research outputs found

    The Impact of baryonic physics on the kinetic Sunyaev-Zel'dovich Effect

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    Poorly understood "baryonic physics" impacts our ability to predict the power spectrum of the kinetic Sunyaev-Zel'dovich (kSZ) effect. We study this in one sample high resolution simulation of galaxy formation and feedback, Illustris. The high resolution of Illustris allows us to probe the kSZ power spectrum on multipoles ℓ=103−3×104\ell =10^3-3\times 10^4. Strong AGN feedback in Illustris nearly wipes out gas fluctuations at k≳1 h Mpc−1k\gtrsim1~h~\rm{Mpc}^{-1} and at late times, likely somewhat under predicting the kSZ power generated at z≲1z\lesssim 1. The post-reionization kSZ power spectrum for Illustris is well-fit by Dℓz<6=1.38[ℓ/3000]0.21 μK2\mathcal{D}^{z<6}_{\ell} = 1.38[\ell/3000]^{0.21}~\mu K^2 over 3000≲ℓ≲100003000\lesssim\ell\lesssim10000, somewhat lower than most other reported values but consistent with the analysis of Shaw et al. Our analysis of the bias of free electrons reveals subtle effects associated with the multi-phase gas physics and stellar fractions that affect even linear scales. In particular there are fewer electrons in biased galaxies, due to gas cooling and star formation, and this leads to an electron bias less than one even at low wavenumbers. The combination of bias and electron fraction that determines the overall suppression is relatively constant, fe2be02∼0.7f_e^2b^2_{e0} \sim 0.7, but more simulations are needed to see if this is Illustris-specific. By separating the kSZ power into different terms, we find at least 6 (10)%6\, (10)\% of the signal at ℓ=3000 (10000)\ell=3000\, (10000) comes from non-Gaussian connected four-point density and velocity correlations, \left_{c}, even without correcting for the Illustris simulation box size. A challenge going forward will be to accurately model long-wave velocity modes simultaneously with Illustris-like high resolution to capture the complexities of galaxy formation and its correlations with large scale flows.Comment: 12 pages, 9 figure, submitted to Ap

    Topology of COBE Microwave Background Fluctuations

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    We have measured the topology (genus) of the fluctuations in the cosmic microwave background seen in the recently completed (four-year) data set produced by the COBE satellite. We find that the genus is consistent with that expected from a random-phase Gaussian distribution, as might be produced naturally in inflationary models.Comment: 2 pages, one Post-Script figure, MNRAS LaTeX Style (mn.sty), submitted to MNRA

    Activation of TLR3 in keratinocytes increases expression of genes involved in formation of the epidermis, lipid accumulation, and epidermal organelles.

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    Injury to the skin, and the subsequent release of noncoding double-stranded RNA (dsRNA) from necrotic keratinocytes, has been identified as an endogenous activator of Toll-like receptor 3 (TLR3). As changes in keratinocyte growth and differentiation follow injury, we hypothesized that TLR3 might trigger some elements of the barrier repair program in keratinocytes. dsRNA was observed to induce TLR3-dependent increases in human keratinocyte mRNA abundance for ABCA12 (ATP-binding cassette, sub-family A, member 12), glucocerebrosidase, acid sphingomyelinase, and transglutaminase 1. Additionally, treatment with dsRNA resulted in increases in sphingomyelin and morphologic changes including increased epidermal lipid staining by Oil Red O and TLR3-dependent increases in lamellar bodies and keratohyalin granules. These observations show that dsRNA can stimulate some events in keratinocytes that are important for skin barrier repair and maintenance

    Andrew Bae Interview

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    Bio: While Andrew Bae is situated in Chicago, he has clients from all over the globe. Born and raised in Seoul, South Korea, Andrew Bae picked up on the business of galleries after attending school and studying chemistry and worked as a chemist for several years. Although his gallery is in one of the more desirable locations of River North, he doesn\u27t seem to carry that many artists. He prefers a limited selection of artists (around 10) as he feels there is more personal connection with his artists especially as a gallery owner. Though the business is changing, Andrew Bae has not sat on the leeway. With the recent economic downturn, many gallery owners have been forced to close their business. Showing his ability to adapt, he recently modified his business model to act as an intermediary and cater to the art collectors in Korea as well. Bio by Richard Par

    Aspects of Disease Activity and Enteral Nutrition in Crohn's Disease

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    The introductory chapters (Chapters 1, 2) reviewed nutritional problems, methods of nutritional support and methods of assessing disease activity in Crohn's disease. Variable prevalences of macro- and micro-nutrient deficiencies occur in patients with Crohn's disease. Previous studies have concentrated on the role of intravenous nutrition for the correction of nutritional deficiencies
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