331 research outputs found
On the Impact of Advance Reservations for Energy-Aware Provisioning of Bare-Metal Cloud Resources
International audienceThis work investigates factors that can impact the elasticity of bare-metal resources. We analyse data from a real bare-metal deployment system to build a deployment time model, which is used to evaluate how provisioning time impacts the reservation of bare-metal resources. Climate/Blazar, a reservation framework designed for OpenStack, is discussed. Simulation results show that reservations can help reduce the time to deliver a provisioned cluster to its customer while achieving energy savings similar to those of strategies that switch-off idle resources
On the Impact of Advance Reservations for Energy-Aware Provisioning of Bare-Metal Cloud Resources
International audienceThis work investigates factors that can impact the elasticity of bare-metal resources. We analyse data from a real bare-metal deployment system to build a deployment time model, which is used to evaluate how provisioning time impacts the reservation of bare-metal resources. Climate/Blazar, a reservation framework designed for OpenStack, is discussed. Simulation results show that reservations can help reduce the time to deliver a provisioned cluster to its customer while achieving energy savings similar to those of strategies that switch-off idle resources
Surface Smoothing: A Way Back in Early Brain
Abstract. In this article we propose to investigate the analogy between early cortical folding process and cortical smoothing by mean curvature flow. First, we introduce a one-parameter model that is able to fit a developmental trajectory as represented in a Volume-Area plot and we propose an efficient optimization strategy for parameter estimation. Second, we validate the model on forty cortical surfaces of preterm newborns by comparing global geometrical indices and trajectories of central sulcus along developmental and simulation time.
Transcriptome analysis of porcine PBMCs after in vitro stimulation by LPS or PMA/ionomycin using an expression array targeting the pig immune response
<p>Abstract</p> <p>Background</p> <p>Designing sustainable animal production systems that better balance productivity and resistance to disease is a major concern. In order to address questions related to immunity and resistance to disease in pig, it is necessary to increase knowledge on its immune system and to produce efficient tools dedicated to this species.</p> <p>Results</p> <p>A long-oligonucleotide-based chip referred to as SLA-RI/NRSP8-13K was produced by combining a generic set with a newly designed SLA-RI set that targets all annotated loci of the pig major histocompatibility complex (MHC) region (SLA complex) in both orientations as well as immunity genes outside the SLA complex.</p> <p>The chip was used to study the immune response of pigs following stimulation of porcine peripheral blood mononuclear cells (PBMCs) with lipopolysaccharide (LPS) or a mixture of phorbol myristate acetate (PMA) and ionomycin for 24 hours. Transcriptome analysis revealed that ten times more genes were differentially expressed after PMA/ionomycin stimulation than after LPS stimulation. LPS stimulation induced a general inflammation response with over-expression of SAA1, pro-inflammatory chemokines IL8, CCL2, CXCL5, CXCL3, CXCL2 and CCL8 as well as genes related to oxidative processes (SOD2) and calcium pathways (S100A9 and S100A12). PMA/ionomycin stimulation induced a stronger up-regulation of T cell activation than of B cell activation with dominance toward a Th1 response, including IL2, CD69 and TNFRSF9 (tumor necrosis factor receptor superfamily, member 9) genes. In addition, a very intense repression of THBS1 (thrombospondin 1) was observed. Repression of MHC class I genes was observed after PMA/ionomycin stimulation despite an up-regulation of the gene cascade involved in peptide processing. Repression of MHC class II genes was observed after both stimulations. Our results provide preliminary data suggesting that antisense transcripts mapping to the SLA complex may have a role during immune response.</p> <p>Conclusion</p> <p>The SLA-RI/NRSP8-13K chip was found to accurately decipher two distinct immune response activations of PBMCs indicating that it constitutes a valuable tool to further study immunity and resistance to disease in pig. The transcriptome analysis revealed specific and common features of the immune responses depending on the stimulation agent that increase knowledge on pig immunity.</p
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The Latest Mars Climate Database (MCD v5.1)
For many years, several teams around the world have developed GCMs (General Circulation Model or Global Climate Model) to simulate the environment on Mars. The GCM developed at the Laboratoire de Météorologie Dynamique in collaboration with several teams in Europe (LATMOS, France, University of Oxford, The Open University, the Instituto de Astrofisica de Andalucia), and with the support of ESA and CNES is currently used for many applications. Its outputs have also regularly been compiled to build a Mars Climate Database, a freely available tool useful for the scientific and engineering communities. The Mars Climate Database (MCD) has over the years been distributed to more than 150 teams around the world. Following the recent improvements in the GCM, a new series of reference simulations have been run and compiled into a new version (version5.1) of the Mars Climate Database, released in the first half of 2014.
To summarize, MCD v5.1 provides:
- Climatologies over a series of dust scenarios: standard year, cold (ie: low dust), warm (ie: dusty atmosphere) and dust storm, all topped by various cases of Extreme UV solar inputs (low, mean or maximum). These scenarios differ from those of previous versions of the MCD (version 4.x) as they have been derived from home-made, instrument-derived (TES, THEMIS, MCS, MERs), dust climatology of the last 8 Martian years.
- Mean values and statistics of main meteorological variables (atmospheric temperature, density, pressure and winds), as well as surface pressure and temperature, CO2 ice cover, thermal and solar radiative fluxes, dust column opacity and mixing ratio, [H20] vapor and ice columns, concentrations of many species: [CO], [O2], [O], [N2], [H2], [O3], ...
- A high resolution mode which combines high resolution (32 pixel/degree) MOLA topography records and Viking Lander 1 pressure records with raw lower resolution GCM results to yield, within the restriction of the procedure, high resolution values of atmospheric variables.
- The possibility to reconstruct realistic conditions by combining the provided climatology with additional large scale and small scale perturbations schemes.
At EGU, we will report on the latest improvements in the Mars Climate Database, with comparisons with available measurements from orbit (e.g.: TES, MCS) or landers (Viking, Phoenix, MSL)
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Modeling the martian atmosphere with the LMD global climate model
Our Global Climate Model (GCM) of the Martian atmosphere is the result of twenty years of ongoing collaboration between our teams and has matured to the point of enabling to study the main cycles (dust, CO2, water) of present-day and past Martian climates.
At the 2014 scientific assembly, we will report on the latest developments and improvements of our GCM, and also present the latest version of the Mars Climate Database (version 5.1) that is derived from GCM outputs, along with comparisons with available measurements (from TES, MCS, Viking, Phoenix, Curiosity, etc.)
Recurrent dust formation by WR 48a on a 30-year timescale
We present infrared photometry of the WC8 Wolf-Rayet system WR 48a observed
with telescopes at ESO, the SAAO and the AAT between 1982 and 2011 which show a
slow decline in dust emission from the previously reported outburst in 1978--79
until about 1997, when significant dust emission was still evident. This was
followed by a slow rise, accelerating to reach and overtake the first (1978)
photometry, demonstrating that the outburst observed in 1978--79 was not an
isolated event, but that they recur at intervals of 32+ years. This suggests
that WR 48a is a long-period dust maker and colliding-wind binary (CWB). The
locus of WR 48a in the (H-L), K colour-magnitude diagram implies that the rate
of dust formation fell between 1979 and about 1997 and then increased steadily
until 2011. Superimposed on the long-term variation are secondary (`mini')
eruptions in (at least) 1990, 1994, 1997, 1999 and 2004, characteristic of
relatively brief episodes of additional dust formation. Spectra show evidence
for an Oe or Be companion to the WC8 star, supporting the suggestion that WR
48a is a binary system and indicating a system luminosity consistent with the
association of WR 48a and the young star clusters Danks 1 and Danks 2. The
range of dust formation suggests that these stars are in an elliptical orbit
having e ~ 0.6. The size of the orbit implied by the minimum period, together
with the WC wind velocity and likely mass-loss rate, implies that the
post-shock WC wind is adiabatic throughout the orbit -- at odds with the
observed dust formation. A similar conflict is observed in the `pinwheel'
dust-maker WR 112.Comment: 15 pages, 8 figures, accepted for publication in MNRA
Exploring the possibility space: taking stock of the diverse capabilities and gaps in integrated assessment models
Abstract
Integrated assessment models (IAMs) have emerged as key tools for building and assessing long term climate mitigation scenarios. Due to their central role in the recent IPCC assessments, and international climate policy analyses more generally, and the high uncertainties related to future projections, IAMs have been critically assessed by scholars from different fields receiving various critiques ranging from adequacy of their methods to how their results are used and communicated. Although IAMs are conceptually diverse and evolved in very different directions, they tend to be criticised under the umbrella of ‘IAMs’. Here we first briefly summarise the IAM landscape and how models differ from each other. We then proceed to discuss six prominent critiques emerging from the recent literature, reflect and respond to them in the light of IAM diversity and ongoing work and suggest ways forward. The six critiques relate to (a) representation of heterogeneous actors in the models, (b) modelling of technology diffusion and dynamics, (c) representation of capital markets, (d) energy-economy feedbacks, (e) policy scenarios, and (f) interpretation and use of model results.</jats:p
Privilèges honorifiques ou avantages contractuels ? Observations sur quelques documents épigraphiques ambigus
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