Search results for "LIMIT"
showing 10 items of 2826 documents
Asbestos: decontamination works and use of individual protection devices. Some remarks on the right use of IPD, considering the cost-benefit relation
2004
Précisions sur la responsabilité du gérant SARL à l'égard des associés
2013
International audience; Note sous Cour de cassation (com.) 10 juillet 2012, F-D, n° 11-22.146, Ferhat c/ Nemmar
GW170817, General Relativistic Magnetohydrodynamic Simulations, and the Neutron Star Maximum Mass
2017
Recent numerical simulations in general relativistic magnetohydrodynamics (GRMHD) provide useful constraints for the interpretation of the GW170817 discovery. Combining the observed data with these simulations leads to a bound on the maximum mass of a cold, spherical neutron star (the TOV limit): ${M_{\rm max}^{\rm sph}}\lesssim 2.74/\beta$, where $\beta$ is the ratio of the maximum mass of a uniformly rotating neutron star (the supramassive limit) over the maximum mass of a nonrotating star. Causality arguments allow $\beta$ to be as high as $1.27$, while most realistic candidate equations of state predict $\beta$ to be closer to $1.2$, yielding ${M_{\rm max}^{\rm sph}}$ in the range $2.16…
A search for point sources of EeV neutrons
2012
A thorough search of the sky exposed at the Pierre Auger Cosmic Ray Observatory reveals no statistically significant excess of events in any small solid angle that would be indicative of a flux of neutral particles from a discrete source. The search covers from −90◦ to +15◦ in declination using four different energy ranges above 1 EeV (1018 eV). The method used in this search is more sensitive to neutrons than to photons. The upper limit on a neutron flux is derived for a dense grid of directions for each of the four energy ranges. These results constrain scenarios for the production of ultrahigh energy cosmic rays in the Galaxy.
Femtolensing by dark matter revisited
2018
Femtolensing of gamma ray bursts (GRBs) has been put forward as an exciting possibility to probe exotic astrophysical objects with masses below $10^{-13}$ solar masses such as small primordial black holes or ultra-compact dark matter minihalos, made up for instance of QCD axions. In this paper we critically review this idea, properly taking into account the extended nature of the source as well as wave optics effects. We demonstrate that most GRBs are inappropriate for femtolensing searches due to their large sizes. This removes the previous femtolensing bounds on primordial black holes, implying that vast regions of parameter space for primordial black hole dark matter are not robustly con…
Temperature-related mortality impacts under and beyond Paris Agreement climate change scenarios.
2018
The Paris Agreement binds all nations to undertake ambitious efforts to combat climate change, with the commitment to hold warming well below 2 degrees C in global mean temperature (GMT), relative to pre-industrial levels, and to pursue efforts to limit warming to 1.5 degrees C. The 1.5 degrees C limit constitutes an ambitious goal for which greater evidence on its benefits for health would help guide policy and potentially increase the motivation for action. Here we contribute to this gap with an assessment on the potential health benefits, in terms of reductions in temperature-related mortality, derived from the compliance to the agreed temperature targets, compared to more extreme warmin…
Anthropogenic Perturbations to the Atmospheric Molybdenum Cycle
2021
Molybdenum (Mo) is a key cofactor in enzymes used for nitrogen (N) fixation and nitrate reduction, and the low availability of Mo can constrain N inputs, affecting ecosystem productivity. Natural atmospheric Mo aerosolization and deposition from sources such as desert dust, sea‐salt spray, and volcanoes can affect ecosystem function across long timescales, but anthropogenic activities such as combustion, motor vehicles, and agricultural dust have accelerated the natural Mo cycle. Here we combined a synthesis of global atmospheric concentration observations and modeling to identify and estimate anthropogenic sources of atmospheric Mo. To project the impact of atmospheric Mo on terrestrial ec…
Determination of alkylamines in atmospheric aerosol particles: a comparison of gas chromatography–mass spectrometry and ion chromatography approaches
2014
Abstract. In recent years low molecular weight alkylamines have been recognized to play an important role in particle formation and growth in the lower atmosphere. However, major uncertainties are associated with their atmospheric processes, sources and sinks, mostly due to the lack of ambient measurements and the difficulties in accurate quantification of alkylamines at trace level. In this study, we present the evaluation and optimization of two analytical approaches, i.e., gas chromatography–mass spectrometry (GC-MS) and ion chromatography (IC), for the determination of alkylamines in aerosol particles. Alkylamines were converted to carbamates through derivatization with isobutyl chlorof…
Atmospheric correction and determination of sea surface temperature in midlatitudes from NOAA-AVHRR data
1993
Abstract In this paper we derive and validate a split-window algorithm for retrieving the sea surface temperature (SST) in midlatitude atmospheric conditions. First we have analyzed thephysical fundamentals of the split-window approach. Then an algorithm has been theoretically derived by means of statistical regression over satellite measurement simulations, and it has been tuned for real NOAA-AVHRR measurements using in situ and coincident satellite data. The accuracy achieved for SST is 0.5 K, which is the limit accuracy that can be obtained from AVHRR measurements over midlatitudes. On the other side, we have proposed a strategy for applying the split-window algorithm without significant…
Organosulfates in atmospheric aerosol: synthesis and quantitative analysis of pm<sub>2.5</sub> from xi'an, northwestern c…
2018
Abstract. The sources, formation mechanism and amount of organosulfates (OS) in atmospheric aerosol are not yet well understood, partly due to the lack of authentic standards for quantification. In this study, we report an improved robust procedure for the synthesis of organosulfates with different functional groups. Nine authentic organosulfate standards were synthesized and four standards (benzyl sulfate, phenyl sulfate, glycolic acid sulfate, and hydroxyacetone sulfate) were used to quantify their ambient concentrations. The authentic standards and ambient aerosol samples were analyzed using an optimized ultra performance liquid chromatography–electrospray ionization-tandem mass spectrom…