1,124 research outputs found

    RATIONAL RECONSTRUCTIONS AND ARCHITECTURAL KNOWLEDGE

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    Stanford Anderson is Professor of History and Architecture and was Head of the Department of Architecture from 1991 through 2004. He was director of MIT’s PhD program in History, Theory and Criticism of Architecture, Art and Urban Form from its founding in 1974 to 1991 and in 1995-96. Anderson’s research and writing concern architectural theory, early modern architecture in northern Europe, American architecture and urbanism, and epistemology and historiography. He has organized numerous professional conferences and served on the editorial boards of Assemblage, Journal of Architectural Education, Places, and The MIT Press. In addition to numerous articles, his books are Planning for Diversity and Choice, On Streets, and Hermann Muthesius: Style-Architecture and Building Art. He is co-author of Kay Fisker. Peter Behrens and a New Architecture for the Twentieth Century appeared in 2000 and Eladio Dieste: Innovation in Structural Art in 2004. In 1997, The MIT Press published a collection of essays in his honor, edited by Martha Pollak: The Education of the Architect: Historiography, Urbanism, and the Growth of Knowledge. He was a Fulbright fellow at the Technische Hochschule in Munich and subsequently a fellow of the John Simon Guggenheim Foundation and the American Council of Learned Societies. Anderson received his bachelor’s degree from the University of Minnesota, his master’s in architecture from the University of California at Berkeley, and his doctoral degree in the history of art from Columbia University in New York City

    Diseño industrial, una estrategia para la unión de la tecnología y el arte

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    En Alemania, el diseño industrial se conoce como Formgebung. El diseño industrial de Peter Behrens, reconocido como uno de los primeros “proveedores de forma”, puede servir de punto de partida para examinar la compleja relaciĂłn entre tĂ©cnica y forma artĂ­stica, y entre forma y buen uso, en las primeras dĂ©cadas del s. XX

    Radial velocities of five globular clusters obtained with AAOmega

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    Using the recently commissioned multi-object spectrograph AAOmega on the 3.9m AAT we have obtained medium-resolution near-infrared spectra for 10,500 stars in and around five southern globular clusters. The targets were 47 Tuc, M12, M30, M55 and NGC 288. We have measured radial velocities to +/- 1 km/s with the cross correlation method and estimated metallicity, effective temperature, surface gra vity and rotational velocity for each star by fitting synthetic model spectra. An analysis of the velocity maps and velocity dispersion of member stars revealed systemic rotation in four of the target clusters.Comment: 4 pages, 6 figures, accepted for publication by Astronomische Nachrichte

    The C+N+O abundance of Omega Centauri giant stars: implications on the chemical enrichment scenario and the relative ages of different stellar populations

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    We present a chemical-composition analysis of 77 red-giant stars in Omega Centauri. We have measured abundances for carbon and nitrogen, and combined our results with abundances of O, Na, La, and Fe that we determined in our previous work. Our aim is to better understand the peculiar chemical-enrichment history of this cluster, by studying how the total C+N+O content varies among the different-metallicity stellar groups, and among stars at different places along the Na-O anticorrelation. We find the (anti)correlations among the light elements that would be expected on theoretical ground for matter that has been nuclearly processed via high-temperature proton captures. The overall [(C+N+O)/Fe] increases by 0.5 dex from [Fe/H] -2.0 to [Fe/H] -0.9. Our results provide insight into the chemical-enrichment history of the cluster, and the measured CNO variations provide important corrections for estimating the relative ages of the different stellar populations.Comment: 26 pages, 9 figure - Accepted for publication in Ap

    Radial distribution of the multiple stellar populations in omega Centauri

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    We present a detailed study of the radial distribution of the multiple populations identified in the Galactic globular cluster omega Cen. We used both space-based images (ACS/WFC and WFPC2) and ground-based images (FORS1@VLT and [email protected] ESO telescopes) to map the cluster from the inner core to the outskirts (~20 arcmin). These data sets have been used to extract high-accuracy photometry for the construction of color-magnitude diagrams and astrometric positions of ~900 000 stars. We find that in the inner ~2 core radii the blue main sequence (bMS) stars slightly dominate the red main sequence (rMS) in number. At greater distances from the cluster center, the relative numbers of bMS stars with respect to rMS drop steeply, out to ~8 arcmin, and then remain constant out to the limit of our observations. We also find that the dispersion of the Gaussian that best fits the color distribution within the bMS is significantly greater than the dispersion of the Gaussian that best fits the color distribution within the rMS. In addition, the relative number of intermediate-metallicity red-giant-branch stars which includes the progeny of the bMS) with respect to the metal-poor component (the progeny of the rMS) follows a trend similar to that of the main-sequence star-count ratio N_bMS/N_rMS. The most metal-rich component of the red-giant branch follows the same distribution as the intermediate-metallicity component. We briefly discuss the possible implications of the observed radial distribution of the different stellar components in omega Cen.Comment: 16 pages, 14 figures (6 in low resolution), 3 tables. Accepted for publication in Astronomy and Astrophysics on 23 September 200

    Star Formation Activities of Galaxies in the Large-Scale Structures at z=1.2

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    Recent wide-field imaging observations of the X-ray luminous cluster RDCSJ1252.9-2927 at z=1.24 uncovered several galaxy groups that appear to be embedded in filamentary structure extending from the cluster core. We make a spectroscopic study of the galaxies in these groups using GMOS on Gemini-South and FORS2 on VLT with the aim of determining if these galaxies are physically associated to the cluster. We find that three groups contain galaxies at the cluster redshift and that they are probably bound to the cluster. This is the first confirmation of filamentary structure as traced by galaxy groups at z>1. We then use several spectral features in the FORS2 spectra to determine the star formation histories of group galaxies. We find a population of relatively red star-forming galaxies in the groups that are absent from the cluster core. While similarly red star forming galaxies can also be found in the field, the average strength of the hd line is systematically weaker in group galaxies. Interestingly, these groups at z=1.2 are in an environment in which the on-going build-up of red sequence is happening. The unusual line strengths can be explained by star formation that is heavily obscured by dust. We hypothesize that galaxy-galaxy interactions, which is more efficient in the group environment, is the mechanism that drives these dust obscured star formation. The hypothesis can be tested by obtaining spectral observations in the near-IR, high resolution imaging observations and observations in the mid-IR.Comment: 12 pages, 12 figures. Accepted for publication in A&

    The Environmental Dependence of Properties of Galaxies around the RDCSJ0910+54 Cluster at z=1.1

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    (Abridged) We report on the environmental dependence of properties of galaxies around the RDCSJ0910+54 cluster at z=1.1. We have obtained multi-band wide-field images of the cluster with Suprime-Cam and MOIRCS on Subaru and WFCAM on UKIRT. Also, an intensive spectroscopic campaign has been carried out using LRIS on Keck and FOCAS on Subaru. We discover a possible large-scale structure around the cluster in the form of three clumps of galaxies. This is potentially one of the largest structures found so far in the z>1 Universe. We then examine stellar populations of galaxies in the structure. Red galaxies have already become the dominant population in the cores of rich clusters at z~1, and the fraction of red galaxies has not strongly changed since then. The red fraction depends on richness of clusters in the sense that it is higher in rich clusters than in poor groups. The luminosity function of red galaxies in rich clusters is consistent with that in local clusters. On the other hand, luminosity function of red galaxies in poor groups shows a deficit of faint red galaxies. This confirms our earlier findings that galaxies follow an environment-dependent down-sizing evolution. There seems to be a large variation in the evolutionary phases of galaxies in groups with similar masses. Further studies of high-z clusters will be a promising way of addressing the role of nature and nurture effects on galaxy evolution.Comment: 11 pages, 10 figures, accepted for publication in A&

    SUcceSS, SUrgery for Spinal Stenosis: Protocol of a randomised, placebo-controlled trial

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    © Author(s) (or their employer(s)) 2019. Introduction: Central lumbar spinal stenosis (LSS) is a common cause of pain, reduced function and quality of life in older adults. Current management of LSS includes surgery to decompress the spinal canal and alleviate symptoms. However, evidence supporting surgical decompression derives from unblinded randomised trials with high cross-over rates or cohort studies showing modest benefits. This protocol describes the design of the SUrgery for Spinal Stenosis (SUcceSS) trial-the first randomised placebo-controlled trial of decompressive surgery for symptomatic LSS. Methods and analysis: SUcceSS will be a prospectively registered, randomised placebo-controlled trial of decompressive spinal surgery. 160 eligible participants (80 participants/group) with symptomatic LSS will be randomised to either surgical spinal decompression or placebo surgical intervention. The placebo surgical intervention is identical to surgical decompression in all other ways with the exception of the removal of any bone or ligament. All participants and assessors will be blinded to treatment allocation. Outcomes will be assessed at baseline and at 3, 6, 12 and 24 months. The coprimary outcomes will be function measured with the Oswestry Disability Index and the proportion of participants who have meaningfully improved their walking capacity at 3 months postrandomisation. Secondary outcomes include back pain intensity, lower limb pain intensity, disability, quality of life, anxiety and depression, neurogenic claudication score, perceived recovery, treatment satisfaction, adverse events, reoperation rate and rehospitalisation rate. Those who decline to be randomised will be invited to participate in a parallel observational cohort. Data analysis will be blinded and by intention to treat. A trial-based cost-effectiveness analysis will determine the potential incremental cost per quality-adjusted life year gained. Ethics and dissemination: Ethics approval has been granted by the NSW Health (reference:17/247/POWH/601) and the Monash University (reference: 12371) Human Research Ethics Committees. Dissemination of results will be via journal articles and presentations at national and international conferences

    Chimpanzees Share Forbidden Fruit

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    The sharing of wild plant foods is infrequent in chimpanzees, but in chimpanzee communities that engage in hunting, meat is frequently used as a ‘social tool’ for nurturing alliances and social bonds. Here we report the only recorded example of regular sharing of plant foods by unrelated, non-provisioned wild chimpanzees, and the contexts in which these sharing behaviours occur. From direct observations, adult chimpanzees at Bossou (Republic of Guinea, West Africa) very rarely transferred wild plant foods. In contrast, they shared cultivated plant foods much more frequently (58 out of 59 food sharing events). Sharing primarily consists of adult males allowing reproductively cycling females to take food that they possess. We propose that hypotheses focussing on ‘food-for-sex and -grooming’ and ‘showing-off’ strategies plausibly account for observed sharing behaviours. A changing human-dominated landscape presents chimpanzees with fresh challenges, and our observations suggest that crop-raiding provides adult male chimpanzees at Bossou with highly desirable food commodities that may be traded for other currencies

    From the CMD of Omega Centauri and (super-)AGB stellar models to a Galactic plane passage gas purging chemical evolution scenario

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    [Abbreviated] We have investigated the color-magnitude diagram of Omega Centauri and find that the blue main sequence (bMS) can be reproduced only by models that have a of helium abundance in the range Y=0.35-0.40.Toexplainthefaintsubgiantbranchofthereddeststars("MS−a/RG−a"sequence),isochronesfortheobservedmetallicity([Fe/H]≈0.7)appeartorequirebothahighage( 13Gyr)andenhancedCNOabundances([CNO/Fe]≈0.90.40. To explain the faint subgiant branch of the reddest stars ("MS-a/RG-a" sequence), isochrones for the observed metallicity ([Fe/H]\approx0.7) appear to require both a high age (~13Gyr) and enhanced CNO abundances ([CNO/Fe]\approx0.9). Y~0.35 must also be assumed in order to counteract the effects of high CNO on turnoff colors, and thereby to obtain a good fit to the relatively blue turnoff of this stellar population. This suggest a short chemical evolution period of time (<1Gyr) for Omega Cen. Our intermediate-mass (super-)AGB models are able to reproduce the high helium abundances, along with [N/Fe]~2 and substantial O depletions if uncertainties in the treatment of convection are fully taken into account. These abundance features distinguish the bMS stars from the dominant [Fe/H] ≈1.7\approx1.7 population. The most massive super-AGB stellar models (M_zams>=6.8M_sun, M_He,core>=1.245M_sun) predict too large N-enhancements, which limits their role in contributing to the extreme populations. We show quantitatively that highly He- and N-enriched AGB ejecta have particularly efficient cooling properties. Based on these results and on the reconstruction of the orbit of Omega Cen with respect to the Milky Way we propose the galactic plane passage gas purging scenario for the chemical evolution of this cluster. Our model addresses the formation and properties of the bMS population (including their central location in the cluster). We follow our model descriptively through four passage events, which could explain not only some key properties of the bMS, but also of the MS-a/RGB-a and the s-enriched stars.Comment: Accepted for publication in ApJ. 10 figures, 5 tables, 21 page
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