838 research outputs found

    FERENGI: Redshifting galaxies from SDSS to GEMS, STAGES and COSMOS

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    We describe the creation of a set of artificially "redshifted" galaxies in the range 0.1<z<1.1 using a set of ~100 SDSS low redshift (v<7000 km/s) images as input. The intention is to generate a training set of realistic images of galaxies of diverse morphologies and a large range of redshifts for the GEMS and COSMOS galaxy evolution projects. This training set allows other studies to investigate and quantify the effects of cosmological redshift on the determination of galaxy morphologies, distortions and other galaxy properties that are potentially sensitive to resolution, surface brightness and bandpass issues. We use galaxy images from the SDSS in the u, g, r, i, z filter bands as input, and computed new galaxy images from these data, resembling the same galaxies as located at redshifts 0.1<z<1.1 and viewed with the Hubble Space Telescope Advanced Camera for Surveys (HST ACS). In this process we take into account angular size change, cosmological surface brightness dimming, and spectral change. The latter is achieved by interpolating a spectral energy distribution that is fit to the input images on a pixel-to-pixel basis. The output images are created for the specific HST ACS point spread function and the filters used for GEMS (F606W and F850LP) and COSMOS (F814W). All images are binned onto the desired pixel grids (0.03" for GEMS and 0.05" for COSMOS) and corrected to an appropriate point spread function. Noise is added corresponding to the data quality of the two projects and the images are added onto empty sky pieces of real data images. We make these datasets available from our website, as well as the code - FERENGI: "Full and Efficient Redshifting of Ensembles of Nearby Galaxy Images" - to produce datasets for other redshifts and/or instruments.Comment: 11 pages, 10 figures, 3 table

    The environmental dependence of the stellar mass-size relation in STAGES galaxies

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    We present the stellar mass-size relations for elliptical, lenticular, and spiral galaxies in the field and cluster environments using HST/ACS imaging and data from the Space Telescope A901/2 Galaxy Evolution Survey (STAGES). We use a large sample of ~1200 field and cluster galaxies, and a sub-sample of cluster core galaxies, and quantify the significance of any putative environmental dependence on the stellar mass-size relation. For elliptical, lenticular, and high-mass (log M*/M_sun > 10) spiral galaxies we find no evidence to suggest any such environmental dependence, implying that internal drivers are governing their size evolution. For intermediate/low-mass spirals (log M*/M_sun < 10) we find evidence, significant at the 2-sigma level, for a possible environmental dependence on galaxy sizes: the mean effective radius a_e for lower-mass spirals is ~15-20 per cent larger in the field than in the cluster. This is due to a population of low-mass large-a_e field spirals that are largely absent from the cluster environments. These large-a_e field spirals contain extended stellar discs not present in their cluster counterparts. This suggests the fragile extended stellar discs of these spiral galaxies may not survive the environmental conditions in the cluster. Our results suggest that internal physical processes are the main drivers governing the size evolution of galaxies, with the environment possibly playing a role affecting only the discs of intermediate/low-mass spirals.Comment: 16 pages, 10 figures, accepted to MNRA

    TB42: The Mycotoxic Effects of Fungi Isolated from Poultry Feed Ingredients: The Response of Ducklings and Performance of Commercial Broiler Chickens Fed Experimentally Infected Corn Diets

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    The present work, planned to investigate the possibility of mycotoxins occurring in feed ingredients fed to poultry in Maine, was designed with the following objectives: (1) to isolate fungi from poultry feed ingredients; (2) to grow the m separately on corn (the carbohydrate source of poultry rations) for later mixing into the diets; (3) to test the variously infected lots of this corn substrate for mycotoxicity by feeding ducklings, a bioindicator for toxins; (4) to determine the effects of aflatoxin and other mycotoxins from feed ingredients, on the performance of commercial broiler chickens; and (5) to appraise this response as a measure of toxicity of the fungi found in feed ingredients.https://digitalcommons.library.umaine.edu/aes_techbulletin/1159/thumbnail.jp

    Limiting behaviour of Fréchet means in the space of phylogenetic trees

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    As demonstrated in our previous work on T4, the space of phylogenetic trees with four leaves, the topological structure of the space plays an important role in the non-classical limiting behaviour of the sample Fréchet means in T4. Nevertheless, the techniques used in that paper cannot be adapted to analyse Fréchet means in the space Tm of phylogenetic trees with m(⩾5)m(⩾5) leaves. To investigate the latter, this paper first studies the log map of Tm. Then, in terms of a modified version of this map, we characterise Fréchet means in Tm that lie in top-dimensional or co-dimension one strata. We derive the limiting distributions for the corresponding sample Fréchet means, generalising our previous results. In particular, the results show that, although they are related to the Gaussian distribution, the forms taken by the limiting distributions depend on the co-dimensions of the strata in which the Fréchet means lie

    Spatial matter density mapping of the STAGES Abell A901/2 supercluster field with 3D lensing

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    We present weak lensing data from the Hubble Space Telescope(HST)/Space Telescope A901/902 Galaxy Evolution Survey (STAGES) survey to study the three-dimensional spatial distribution of matter and galaxies in the Abell 901/902 supercluster complex. Our method improves over the existing 3D lensing mapping techniques by calibrating and removing redshift bias and accounting for the effects of the radial elongation of 3D structures. We also include the first detailed noise analysis of a 3D lensing map, showing that even with deep HST-quality data, only the most massive structures, for example M200≳ 1015M⊙h-1 at z∼ 0.8, can be resolved in 3D with any reasonable redshift accuracy (Δz≈ 0.15). We compare the lensing map to the stellar mass distribution and find luminous counterparts for all mass peaks detected with a peak significance &gt;3σ. We see structures in and behind the z= 0.165 foreground supercluster, finding structure directly behind the A901b cluster at z∼ 0.6 and also behind the south-west (SW) group at z∼ 0.7. This 3D structure viewed in projection has no significant impact on recent mass estimates of A901b or the SW group components SWa and SWb. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS

    Photon-Photon Luminosities in Relativistic Heavy Ion Collisions at LHC Energies

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    Effective photon-photon luminosities are calculated for various realistic hadron collider scenarios. The main characteristics of photon-photon processes at relativistic heavy-ion colliders are established and compared to the corresponding photon-photon luminosities at electron-positron and future Photon Linear Colliders (PLC). Higher order corrections as well as inelastic processes are discussed. It is concluded that feasible high luminosity Ca-Ca collisions at the Large Hadron Collider (LHC) are an interesting option for photon-photon physics up to about 100 GeV photon-photon CM energy.Comment: REVTeX, 13 pages, 10 figures (uuencoded,compressed postscript

    A randomised controlled trial of succinylated gelatin (4%) fluid on urinary acute kidney injury biomarkers in cardiac surgical patients

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    Background Fluid resuscitation is frequently required for cardiac surgical patients admitted to the intensive care unit. The ideal fluid of choice in regard to efficacy and safety remains uncertain. Compared with crystalloid fluid, colloid fluid may result in less positive fluid balance. However, some synthetic colloids are associated with increased risk of acute kidney injury (AKI). This study compared the effects of succinylated gelatin (4%) (GEL) with compound sodium lactate (CSL) on urinary AKI biomarkers in patients after cardiac surgery. Methods Cardiac surgical patients who required an intravenous fluid bolus of at least 500 mL postoperatively were randomly allocated to receive GEL or CSL as the resuscitation fluid of choice for the subsequent 24 h. Primary outcomes were serial urinary neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C concentrations measured at baseline, 1 h, 5 h and 24 h after enrolment, with higher concentrations indicating greater kidney injury. Secondary biomarker outcomes included urinary clusterin, α1-microglobulin and F2-isoprostanes concentrations. Differences in change of biomarker concentration between the two groups over time were compared with mixed-effects regression models. Statistical significance was set at P < 0.05. Results Forty cardiac surgical patients (n = 20 per group) with similar baseline characteristics were included. There was no significant difference in the median volume of fluid boluses administered over 24 h between the GEL (1250 mL, Q1–Q3 500–1750) and CSL group (1000 mL, Q1–Q3 500–1375) (P = 0.42). There was a significantly greater increase in urinary cystatin C (P < 0.001), clusterin (P < 0.001), α1-microglobulin (P < 0.001) and F2-isoprostanes (P = 0.020) concentrations over time in the GEL group, compared to the CSL group. Change in urinary NGAL concentration (P = 0.68) over time was not significantly different between the groups. The results were not modified by adjustment for either urinary osmolality or EuroSCORE II predicted risk of mortality. Conclusions This preliminary randomised controlled trial showed that use of succinylated gelatin (4%) for fluid resuscitation after cardiac surgery was associated with increased biomarker concentrations of renal tubular injury and dysfunction, compared to crystalloid fluid. These results generate concern that use of intravenous gelatin fluid may contribute to clinically relevant postoperative AKI

    The hidden HI-massive LIRG HIZOA J0836-43: Inside-out galaxy formation

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    HIZOA J0836-43 is an extreme gas-rich (MHIM_{\rm{HI}}=7.5\times10^{10} M_{\sun}) disk galaxy which lies hidden behind the strongly obscuring Vela region of the Milky Way. Utilizing observations from the {\it Spitzer Space Telescope}, we have found it to be a luminous infrared starburst galaxy with a star formation rate of \sim 21 M_{\sun} \rm{yr^{-1}}, arising from exceptionally strong molecular PAH emission (L_{7.7\micron} = 1.50 \times 10^{9} L_{\odot}) and far-infrared emission from cold dust. The galaxy exhibits a weak mid-infrared continuum compared to other starforming galaxies and U/LIRGs. This relative lack of emission from small grains suggests atypical interstellar medium conditions compared to other starbursts. We do not detect significant [[Ne {\sc v}]] or [[O {\sc iv}]], which implies an absent or very weak AGN. The galaxy possesses a prominent bulge of evolved stars and a stellar mass of 4.4(±\pm1.4)\times10^{10} M_{\sun}. With its plentiful gas supply and current star formation rate, a doubling of stellar mass would occur on a timescale of \sim2 Gyr. Compared to local galaxies, HIZOA J0836-43 appears to be a "scaled-up" spiral undergoing inside-out formation, possibly resembling stellar disk building processes at intermediate redshifts.Comment: 5 pages, 3 figures, 1 table; Accepted for publication in ApJL: August 25 2008. A version with full resolution figures is available at http://spider.ipac.caltech.edu/staff/jarrett/Cluver_ApJL.pd

    Playing dice with mice: building experimental futures in Singapore

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    This is a postprint of an article published in New Genetics and Society, 2011, Vol. 30, Issue 4 pp. 433 – 441 © 2011 copyright Taylor & Francis. New Genetics and Society is available online at: http://www.tandfonline.com/loi/cngs20#.UqsI0tJdU24This short paper adds to debates on the unfolding spaces and logics of biotechnological development bought together in the 2009 special issue of New Genetics and Society on ‘Biopolitics in Asia’. Though an unlikely comparison between the development of the genomic sciences and the building of gambling casinos in the city state of Singapore, it reflects on the nature of political and technological investments in this South-East Asian city. It argues that Western expectations of a link between scientific practices, and civic epistemologies linked to democratic decision-making, are replaced by a rather different future orientation to scientific experimentation, economic investment and social development in Singapore

    Randomizing world trade. II. A weighted network analysis

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    Based on the misleading expectation that weighted network properties always offer a more complete description than purely topological ones, current economic models of the International Trade Network (ITN) generally aim at explaining local weighted properties, not local binary ones. Here we complement our analysis of the binary projections of the ITN by considering its weighted representations. We show that, unlike the binary case, all possible weighted representations of the ITN (directed/undirected, aggregated/disaggregated) cannot be traced back to local country-specific properties, which are therefore of limited informativeness. Our two papers show that traditional macroeconomic approaches systematically fail to capture the key properties of the ITN. In the binary case, they do not focus on the degree sequence and hence cannot characterize or replicate higher-order properties. In the weighted case, they generally focus on the strength sequence, but the knowledge of the latter is not enough in order to understand or reproduce indirect effects.Comment: See also the companion paper (Part I): arXiv:1103.1243 [physics.soc-ph], published as Phys. Rev. E 84, 046117 (2011
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