1,124 research outputs found
RATIONAL RECONSTRUCTIONS AND ARCHITECTURAL KNOWLEDGE
Stanford Anderson is Professor of History and Architecture and was Head of the Department of Architecture from 1991 through 2004. He was director of MITâs PhD program in History, Theory and Criticism of Architecture, Art and Urban Form from its founding in 1974 to 1991 and in 1995-96. Andersonâs 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 bachelorâs degree from the University of Minnesota, his masterâs 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 uniĂłn de la tecnologĂa y el arte
En Alemania, el diseño industrial se conoce como Formgebung. El diseño industrial de Peter Behrens, reconocido como uno de
los primeros âproveedores de formaâ, 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
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
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
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
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
(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
© 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
The sharing of wild plant foods is infrequent in chimpanzees, but in chimpanzee communities that engage in hunting, meat is frequently used as a âsocial toolâ 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 âfood-for-sex and -groomingâ and âshowing-offâ 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
[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-).
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] 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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