507 research outputs found
Sensibilité d'une analyse coût-bénéfice - Enseignements pour l'évaluation des projets d'atténuation des inondations
National audienceCost-Benefit Analysis based on the damage avoided approach gives rise to several synthetic indicators measuring either the flood exposure of an area (mean annual damage), or the interest to conduct a flood prevention policy (mean annual damage avoided, net present value). Those indicators are the outcome of a combination of hydrological, hydraulic, geographic and economic models. Although it is recommended to study the precision of these indicators, this is rarely done in practice, as the combined models which are needed are relatively complex. In this article, we present an approach which is based on Monte-Carlo analysis, and discuss the insights which can be drawn from it on the validity of the indicators.L'analyse coĂ»t-bĂ©nĂ©fice basĂ©e sur la simulation des dommages Ă©vitĂ©s permet d'obtenir des indicateurs synthĂ©tiques sur l'exposition d'un territoire aux inondations (les dommages moyens annualisĂ©s), ainsi que l'intĂ©rĂȘt ou non de mener une politique de prĂ©vention des inondations (les dommages Ă©vitĂ©s moyens annualisĂ©s, la valeur actuelle nette). Ces indicateurs sont issus de la combinaison de modĂ©lisations hydrologiques, hydrauliques, gĂ©ographiques et Ă©conomiques d'un territoire. Bien qu'il soir recommandĂ© d'en Ă©tudier la prĂ©cision et la sensibilitĂ©, cette Ă©tape n'est que trĂšs rarement effectuĂ©e en pratique, notamment du fait de la complexitĂ© de la combinaison des diffĂ©rents modĂšles mobilisĂ©s. Dans cet article, au travers d'un exemple, nous proposons une approche reposant sur la technique de Monte-Carlo et analysons les enseignements concernant la validitĂ© des indicateurs
Internal vein texture and vein evolution of the epithermal Shila-Paula district, southern Peru.
The epithermal Shila-Paula AuâAg district is characterized by numerous veins hosted in Tertiary volcanic rocks of the Western Cordillera (southern Peru). Field studies of the ore bodies reveal a systematic association of a main EâW vein with secondary N55â60°W veinsâtwo directions that are also reflected by the orientation of fluid-inclusion planes in quartz crystals of the host rock. In areas where this pattern is not recognized, such as the Apacheta sector, vein emplacement seems to have been guided by regional N40°E and N40°W fractures. Two main vein-filling stages are identified. stage 1 is a quartzâadulariaâpyriteâgalenaâsphaleriteâchalcopyriteâelectrumâMn silicateâcarbonate assemblage that fills the main EâW veins. stage 2, which contains most of the precious-metal mineralization, is divided into pre-bonanza and bonanza substages. The pre-bonanza substage consists of a quartzâadulariaâcarbonate assemblage that is observed within the secondary N45â60°W veins, in veinlets that cut the stage 1 assemblage, and in final open-space fillings. The two latter structures are finally filled by the bonanza substage characterized by a Fe-poor sphaleriteâchalcopyriteâpyriteâgalenaâtennantiteâtetrahedriteâpolybasiteâpearceiteâelectrum assemblage. The ore in the main veins is systematically brecciated, whereas the ore in the secondary veins and geodes is characteristic of open-space crystallization. Microthermometric measurements on sphalerite from both stages and on quartz and calcite from stage 2 indicate a salinity range of 0 to 15.5 wt% NaCl equivalent and homogenization temperatures bracketed between 200 and 330°C. Secondary CO2-, N2- and H2S-bearing fluid inclusions are also identified. The age of vein emplacement, based on 40Ar/39Ar ages obtained on adularia of different veins, is estimated at around 11 Ma, with some overlap between adularia of stage 1 (11.4±0.4 Ma) and of stage 2 (10.8±0.3 Ma). A three-phase tectonic model has been constructed to explain the vein formation. Phase 1 corresponds to the assumed development of EâW sinistral shear zones and associated N60°W cleavages under the effects of a NEâSW shortening direction that is recognized at Andean scale. These structures contain the stage 1 ore assemblage that was brecciated during ongoing deformation. Phase 2 is a reactivation of earlier structures under a NWâSE shortening direction that allowed the reopening of the preexisting schistosity and the formation of scarce N50°E-striking S2-cleavage planes filled by the stage 2 pre-bonanza minerals. Phase 3 coincides with the bonanza ore emplacement in the secondary N45â60°W veins and also in open-space in the core of the main EâW veins. Our combined tectonic, textural, mineralogical, fluid-inclusion, and geochronological study presents a complete model of vein formation in which the reactivation of previously formed tectonic structures plays a significant role in ore formation
Diversity of Archaeosine Synthesis in Crenarchaeota
Archaeosine (G+) is found at position 15 of many archaeal tRNAs. In Euryarchaeota, the G+ precursor, 7-cyano-7-deazaguanine (preQ0), is inserted into tRNA by tRNA-guanine transglycosylase (arcTGT) before conversion into G+ by ARChaeosine Synthase (ArcS). However, many Crenarchaeota known to harbor G+ lack ArcS homologs. Using comparative genomics approaches, two families that could functionally replace ArcS in these organisms were identified: 1) GAT-QueC, a two-domain family with an N-terminal glutamine amidotransferase class-II domain fused to a domain homologous to QueC, the enzyme that produces preQ0; 2) QueF-like, a family homologous to the bacterial enzyme catalyzing the reduction of preQ0 to 7- aminomethyl-7-deazaguanine. Here we show that these two protein families are able to catalyze the formation of G+ in a heterologous system. Structure and sequence comparisons of crenarchaeal and euryarchaeal arcTGTs suggest the crenarchaeal enzymes have broader substrate specificity. These results led to a new model for the synthesis and salvage of G+ in Crenarchaeota
Development of a Modular Biosensor System for Rapid Pathogen Detection
Progress in the field of pathogen detection relies on at least one of the following three qualities: selectivity, speed, and cost-effectiveness. Here, we demonstrate a proof of concept for an optical biosensing system for the detection of the opportunistic human pathogen Pseudomonas aeruginosa while addressing the abovementioned traits through a modular design. The biosensor detects pathogen-specific quorum sensing molecules and generates a fluorescence signal via an intracellular amplifier. Using a tailored measurement device built from low-cost components, the image analysis software detected the presence of P. aeruginosa in 42Â min of incubation. Due to its modular design, individual components can be optimized or modified to specifically detect a variety of different pathogens. This biosensor system represents a successful integration of synthetic biology with software and hardware engineering
Rackham: An Interactive Robot-Guide
International audienceRackham is an interactive robot-guide that has been used in several places and exhibitions. This paper presents its design and reports on results that have been obtained after its deployment in a permanent exhibition. The project is conducted so as to incrementally enhance the robot functional and decisional capabilities based on the observation of the interaction between the public and the robot. Besides robustness and efficiency in the robot navigation abilities in a dynamic environment, our focus was to develop and test a methodology to integrate human-robot interaction abilities in a systematic way. We first present the robot and some of its key design issues. Then, we discuss a number of lessons that we have drawn from its use in interaction with the public and how that will serve to refine our design choices and to enhance robot efficiency and acceptability
Higher D or Li: Probes of Physics beyond the Standard Model
Standard Big Bang Nucleosynthesis at the baryon density determined by the
microwave anisotropy spectrum predicts an excess of \li7 compared to
observations by a factor of 4-5. In contrast, BBN predictions for D/H are
somewhat below (but within ~2 \sigma) of the weighted mean of observationally
determined values from quasar absorption systems. Solutions to the \li7 problem
which alter the nuclear processes during or subsequent to BBN, often lead to a
significant increase in the deuterium abundance consistent with the highest
values of D/H seen in absorption systems. Furthermore, the observed D/H
abundances show considerable dispersion. Here, we argue that those systems with
D/H \simeq 4 \times 10^{-5} may be more representative of the primordial
abundance and as a consequence, those systems with lower D/H would necessarily
have been subject to local processes of deuterium destruction. This can be
accounted for by models of cosmic chemical evolution able to destroy in situ
Deuterium due to the fragility of this isotope.Comment: 22 pages, 8 figure
Multidifferential study of identified charged hadron distributions in -tagged jets in proton-proton collisions at 13 TeV
Jet fragmentation functions are measured for the first time in proton-proton
collisions for charged pions, kaons, and protons within jets recoiling against
a boson. The charged-hadron distributions are studied longitudinally and
transversely to the jet direction for jets with transverse momentum 20 GeV and in the pseudorapidity range . The
data sample was collected with the LHCb experiment at a center-of-mass energy
of 13 TeV, corresponding to an integrated luminosity of 1.64 fb. Triple
differential distributions as a function of the hadron longitudinal momentum
fraction, hadron transverse momentum, and jet transverse momentum are also
measured for the first time. This helps constrain transverse-momentum-dependent
fragmentation functions. Differences in the shapes and magnitudes of the
measured distributions for the different hadron species provide insights into
the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb
public pages
Study of the decay
The decay is studied
in proton-proton collisions at a center-of-mass energy of TeV
using data corresponding to an integrated luminosity of 5
collected by the LHCb experiment. In the system, the
state observed at the BaBar and Belle experiments is
resolved into two narrower states, and ,
whose masses and widths are measured to be where the first uncertainties are statistical and the second
systematic. The results are consistent with a previous LHCb measurement using a
prompt sample. Evidence of a new
state is found with a local significance of , whose mass and width
are measured to be and , respectively. In addition, evidence of a new decay mode
is found with a significance of
. The relative branching fraction of with respect to the
decay is measured to be , where the first
uncertainty is statistical, the second systematic and the third originates from
the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb
public pages
New insights into the genetic etiology of Alzheimer's disease and related dementias
Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE Δ4 allele
Measurement of the ratios of branching fractions and
The ratios of branching fractions
and are measured, assuming isospin symmetry, using a
sample of proton-proton collision data corresponding to 3.0 fb of
integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The
tau lepton is identified in the decay mode
. The measured values are
and
, where the first uncertainty is
statistical and the second is systematic. The correlation between these
measurements is . Results are consistent with the current average
of these quantities and are at a combined 1.9 standard deviations from the
predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb
public pages
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