124 research outputs found
La « ville durable » précipitée dans le monde arabe : essai d’analyse généalogique et critique
Articulés à une institutionnalisation progressive du développement urbain durable (DUD), beaucoup de nouveaux chantiers ont été ouverts dans les pays du monde arabe et commencent à se décliner en programmes d’action depuis les années 1990-2000. Ils peuvent être interprétés de manières ambivalentes et contradictoires. D’un côté, l’appropriation du DUD à travers des actions innovantes (programmes d’énergies renouvelables, projets d’éco-quartiers, nouvelles certifications etc.) sert la préservation d’un ordre et la bonne image d’un pouvoir, fût-il autoritaire. De l’autre côté, une véritable conduite de changement de l’action urbaine est amorcée et portée par des acteurs situés dans les « appareils » (agences publiques, ministères, etc.) ou en dehors de ceux-ci (bureaux d’études, associations, ONG), même si nous en soulignons les limites en l’état actuel des choses : éclatement des initiatives qui ne font pas ou peu réseau, invention à peine amorcée de réponses ad hoc qui traduiraient une « endogénéisation » du DUD, par là même différente du travail de reprise des réponses élaborées dans les pays du Nord, et impact encore limité des premiers projets dans la mesure où peu encore était construit et visible en 2012.Linked to a progressive institutionalization of sustainable urban development (SUD), urban policies have changed in the Arab world and action plans begin to be implemented since the years 90-2000. This new trend can be interpreted in an ambivalent and contradictory way. On the one hand, the dissemination of SUD embedded in innovative activities (renewable energy programs, eco-neighborhoods projects, new laws etc.) serve the preservation of the urban order ruled by authoritarian powers. On the other hand, a real change of urban action is initiated and carried by a variety of actors inside the « system » (state agencies, ministries) or from outside (consulting firms, associations, NGOs), although we emphasize in the paper limits in the current situation : fragmentation of initiatives, rare responses that would reflect an « indigenization » of SUD thus different from the recipes of the global North (use of eco-technologies, eco-neighborhoods etc.), and yet limited impact of the first projects to the extent that very few are yet built in 2012
The cosmological analysis of X-ray cluster surveys: I- A new method for interpreting number counts
We present a new method aiming to simplify the cosmological analysis of X-ray
cluster surveys. It is based on purely instrumental observable quantities,
considered in a two-dimensional X-ray colour-magnitude diagram (hardness ratio
versus count-rate). The basic principle is that, even in rather shallow
surveys, substantial information on cluster redshift and temperature is present
in the raw X-ray data and can be statistically extracted; in parallel, such
diagrams can be readily predicted from an ab initio cosmological modeling. We
illustrate the methodology for the case of a 100 deg2 XMM survey having a
sensitivity of ~10^{-14} ergs/s/cm^2 and fit at the same time, the survey
selection function, the cluster evolutionary scaling-relations and the
cosmology; our sole assumption -- driven by the limited size of the sample
considered in the case-study -- is that the local cluster scaling relations are
known. We devote special care to the realistic modeling of the count-rate
measurement uncertainties and evaluate the potential of the method via a Fisher
analysis. In the absence of individual cluster redshifts, the CR-HR method
appears to be much more efficient than the traditional approach based on
cluster counts (i.e. dn/dz, requiring redshifts). In the case where redshifts
are available, our method performs similarly as the traditional mass function
(dn/dM/dz) for the purely cosmological parameters, but better constrains
parameters defining the cluster scaling relations and their evolution. A
further practical advantage of the CR-HR method is its simplicity : this fully
top-down approach totally bypasses the tedious steps consisting in deriving
cluster masses from X-ray temperature measurements.Comment: 18 pages, 15 figures, 3 tables. Accepted for publication in MNRAS
(minor changes with respect to previous version
The ArT\'eMiS wide-field submillimeter camera: preliminary on-sky performances at 350 microns
ArTeMiS is a wide-field submillimeter camera operating at three wavelengths
simultaneously (200, 350 and 450 microns). A preliminary version of the
instrument equipped with the 350 microns focal plane, has been successfully
installed and tested on APEX telescope in Chile during the 2013 and 2014
austral winters. This instrument is developed by CEA (Saclay and Grenoble,
France), IAS (France) and University of Manchester (UK) in collaboration with
ESO. We introduce the mechanical and optical design, as well as the cryogenics
and electronics of the ArTeMiS camera. ArTeMiS detectors are similar to the
ones developed for the Herschel PACS photometer but they are adapted to the
high optical load encountered at APEX site. Ultimately, ArTeMiS will contain 4
sub-arrays at 200 microns and 2x8 sub-arrays at 350 and 450 microns. We show
preliminary lab measurements like the responsivity of the instrument to hot and
cold loads illumination and NEP calculation. Details on the on-sky
commissioning runs made in 2013 and 2014 at APEX are shown. We used planets
(Mars, Saturn, Uranus) to determine the flat-field and to get the flux
calibration. A pointing model was established in the first days of the runs.
The average relative pointing accuracy is 3 arcsec. The beam at 350 microns has
been estimated to be 8.5 arcsec, which is in good agreement with the beam of
the 12 m APEX dish. Several observing modes have been tested, like On-The-Fly
for beam-maps or large maps, spirals or raster of spirals for compact sources.
With this preliminary version of ArTeMiS, we concluded that the mapping speed
is already more than 5 times better than the previous 350 microns instrument at
APEX. The median NEFD at 350 microns is 600 mJy.s1/2, with best values at 300
mJy.s1/2. The complete instrument with 5760 pixels and optimized settings will
be installed during the first half of 2015.Comment: 11 pages, 11 figures. Presented at SPIE Millimeter, Submillimeter,
and Far-Infrared Detectors and Instrumentation for Astronomy VII, June 24,
2014. To be published in Proceedings of SPIE Volume 915
RETRATO SIN IDENTIFICAR [Material gráfico]
Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201
A Chandra view of the z=1.62 galaxy cluster IRC-0218A
Context: Very few z > 1.5 clusters of galaxies are known. It is important to
study the properties of galaxies in these clusters and the ICM and, further, to
cross-check the reliability of the various mass estimates. This will help to
clarify the process of structure formation and how distant clusters may be used
to constrain cosmology. AIMS: We present a 84 ks Chandra observation of
IRC-0218A, a cluster of galaxies inferred by the presence of a galaxy
overdensity in the infrared at a redshift of 1.62 and associated with some XMM
emission Methods: Spatial analysis of the Chandra X-ray photon distribution.
Results: The Chandra observation of IRC-0218A appears to be entirely dominated
by a point-source located at the centroid of the MIR galaxy density. In
addition, we detect weak extended emission (2.3 sigma) out to a radius of 25"
with a flux of ~ 3 10E-15 erg/s/cm2 in the [0.3-2]keV band. Assuming that
clusters evolve similarly, we infer a virial mass of M200 =7.7+/-3.8 10E13Mo.
This is marginally compatible with our current estimate of the cluster
dynamical mass (based on 10 redshifts), although there is no evidence that the
galaxy peculiar velocities correspond to the motions of a virialized structure.
The stellar mass enclosed in the inferred X-ray virial radius is estimated to
1-2 10E12 Mo. We provide a detailed account of 28 X-ray point-sources detected
in the field.Comment: 6 pages, 8 figures, accepted for publication in A&A (minor changes
with respect to the submitted version
Ornithological report 2001-2006 for the Camargue
The present ornithological report for the Camargue covers six years (2001-2006). This time-period has been marked by an accelerated global warming (the summer 2003 was particularly extreme). Owing to a constant high observation
pressure, 18 new species have been recorded and many rare species have been resighted in that region (Camargue, Crau, Alpilles). Among the species or group of species which are regularly censused, the number of breeding Greater Flamingos Phoenicopterus roseus and that of wintering ducks and
coots did not show any significant change. The colonial herons have continued either to increase or to fluctuate at a high level. For example, the Great White Egret Casmerodius albus has definitely settled in the delta and the Squacco Heron Ardeola ralloides has reached a new peak of 505
pairs in 2006. More efficient prospection efforts gave more precise breeding numbers for two species of solitary herons, the Great Bittern Botaurus stellaris and the Little Bittern Ixobrychus minutus. New breeding species such as the Great Cormorant Phalacrocorax carbo, White Stork Ciconia
ciconia, Eurasian Spoonbill Platalea leucorodia and Greylag Anser anser increased their numbers as well as the Glossy Ibis Plegadis falcinellus of which 14 pairs has bred in 2006 and the Purple Swamphen Porphyrio porphyrio which was found for the first time breeding in 2006. The breeding
species showing the most serious concern are actually the breeding gulls and terns whose figures have dramatically decreased. Without human management, this situation will even become worse in a near future. Further remarkable observations were the first case of wintering Lesser Spotted
Eagle Aquila pomarina in 2001/2002, a mixed pair of Black-winged Pratincole Glareola nordmanni x Collared Pratincole G. pratincola in 2001, the settling of the Rook Corvus frugilegus in ArlesCe calendrier ornithologique couvre les six années de 2001 à 2006, une période marquée par un phénomène de réchauffement général accéléré du climat en général et par la canicule de l'été 2003 en particulier. Compte tenu de la
pression d'observation élevée, 18 nouvelles espèces ont été signalées et de nombreuses espèces rares ont été revues dans la région (Camargue, Crau, Alpilles). Parmi les espèces ou groupes d'espèces qui font l'objet de recensements réguliers, les effectifs nicheurs de Flamant rose
Phoenicopterus roseus de même que ceux des Anatidés et des Foulques hivernants n'appellent pas de commentaires particuliers pour ce laps de temps. Les Ardéidés coloniaux continuent soit de progresser pour certains, soit de fluctuer dans des limites qui restent élevées pour d'autres. Par
exemple, la Grande Aigrette Casmerodius albus s'est installée durablement dans le delta, le Crabier chevelu Ardeola ralloides a atteint un nouveau maximum avec 505 couples en 2006. Des effectifs plus précis sont fournis pour deux espèces comme le Butoir étoilé Botaurus stellaris et le
Blongios nain Ixohrychus minutus grâce à des prospections plus efficaces. Des espèces nicheuses d'installation récente comme le Grand Cormoran Phalacrocorax carho, la Cigogne blanche Ciconia ciconia, la Spatule blanche Platalea leucorodia et l'Oie cendrée Anser anser continuent de progresser
de même que l'Ibis falcinelle Plegadis falcinellus dont 14 couples se sont reproduits en 2006 et la Talève sultane Porphyrio porphyrio dont la reproduction a enfin été confirmée en 2006. Parmi les espèces posant un problème grave, il faut relever les laro-limicoles nicheurs dont les
effectifs se sont effondrés. Sans intervention urgente de gestion, leur situation risque d'empirer. Parmi les faits remarquables, signalons le premier cas d'hivernage de l'Aigle pomarin Aquila pomarina en 2001/2002, un couple mixte de Glaréole à ailes noires Glareola nordmanni x Glaréole à
collier G. pratincola en 2001, l'installation du Corbeau freux Corvus frugilegus à Arles
The Hot and Energetic Universe: The evolution of galaxy groups and clusters
Major astrophysical questions related to the formation and evolution of
structures, and more specifically of galaxy groups and clusters, will still be
open in the coming decade and beyond: what is the interplay of galaxy,
supermassive black hole, and intergalactic gas evolution in the most massive
objects in the Universe - galaxy groups and clusters? What are the processes
driving the evolution of chemical enrichment of the hot diffuse gas in
large-scale structures? How and when did the first galaxy groups in the
Universe, massive enough to bind more than 10^7 K gas, form? Focussing on the
period when groups and clusters assembled (0.5<z<2.5), we show that, due to the
continuum and line emission of this hot intergalactic gas at X-ray wavelengths,
Athena+, combining high sensitivity with excellent spectral and spatial
resolution, will deliver breakthrough observations in view of the
aforementioned issues. Indeed, the physical and chemical properties of the hot
intra-cluster gas, and their evolution across time, are a key to understand the
co-evolution of galaxy and supermassive black hole within their environments.Comment: Supporting paper for the science theme The Hot and Energetic Universe
to be implemented by the Athena+ X-ray observatory
(http://www.the-athena-x-ray-observatory.eu). 10 pages, 4 figure
Microsatellite and Mitochondrial Data Provide Evidence for a Single Major Introduction for the Neartic Leafhopper Scaphoideus titanus in Europe
Scaphoideus titanus, a leafhopper native to North America and invasive in Europe, is the vector of the Flavescence dorée phytoplasma, the causal agent of the most important form of grapevine yellows in European vineyards. We studied 10 polymorphic microsatellite loci and a 623 bp fragment of the mitochondrial cytochrome oxidase II gene in native S. titanus from north-eastern America and introduced European populations, to elucidate the colonization scenario. Consistent with their recent history, invasive European populations were less genetically diverse than American populations for both types of markers, suggesting a recent bottleneck. Significant isolation by distance was detected between American populations but not between European populations. None of the European mitochondrial haplotypes was found in the American vineyards, from which they are assumed to have originated. The precise source of the invasive S. titanus populations therefore remains unclear. Nevertheless, the high heterozygosity of North-East American populations (which contained 92% of the observed alleles) suggests that this region is part of the native range of S. titanus. Clustering population genetics analyses with microsatellite and mitochondrial data suggested that European populations originated from a single introduction event. Most of the introduced populations clustered with populations from Long Island, the Atlantic Coast winegrowing region in which Vitis aestivalis occurs
Planck 2013 results. XXIX. Planck catalogue of Sunyaev-Zeldovich sources
We describe the all-sky Planck catalogue of clusters and cluster candidates derived from Sunyaev-Zeldovich (SZ) effect detections using the first 15.5 months of Planck satellite observations. The catalogue contains 1227 entries, making it over six times the size of the Planck Early SZ (ESZ) sample and the largest SZ-selected catalogue to date. It contains 861 confirmed clusters, of which 178 have been confirmed as clusters, mostly through follow-up observations, and a further 683 are previously-known clusters. The remaining 366 have the status of cluster candidates, and we divide them into three classes according to the quality of evidence that they are likely to be true clusters. The Planck SZ catalogue is the deepest all-sky cluster catalogue, with redshifts up to about one, and spans the broadest cluster mass range from (0.1 to 1.6) × 1015 M⊙. Confirmation of cluster candidates through comparison with existing surveys or cluster catalogues is extensively described, as is the statistical characterization of the catalogue in terms of completeness and statistical reliability. The outputs of the validation process are provided as additional information. This gives, in particular, an ensemble of 813 cluster redshifts, and for all these Planck clusters we also include a mass estimated from a newly-proposed SZ-mass proxy. A refined measure of the SZ Compton parameter for the clusters with X-ray counter-parts is provided, as is an X-ray flux for all the Planck clusters not previously detected in X-ray surveys.The development of Planck has been supported by: ESA; CNES and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MICINN and JA (Spain); Tekes, AoF and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN (Norway); SFI (Ireland); FCT/MCTES (Portugal); and PRACE (EU).Peer Reviewe
DMTs and Covid-19 severity in MS: a pooled analysis from Italy and France
We evaluated the effect of DMTs on Covid-19 severity in patients with MS, with a pooled-analysis of two large cohorts from Italy and France. The association of baseline characteristics and DMTs with Covid-19 severity was assessed by multivariate ordinal-logistic models and pooled by a fixed-effect meta-analysis. 1066 patients with MS from Italy and 721 from France were included. In the multivariate model, anti-CD20 therapies were significantly associated (OR = 2.05, 95%CI = 1.39–3.02, p < 0.001) with Covid-19 severity, whereas interferon indicated a decreased risk (OR = 0.42, 95%CI = 0.18–0.99, p = 0.047). This pooled-analysis confirms an increased risk of severe Covid-19 in patients on anti-CD20 therapies and supports the protective role of interferon
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