Jurnal Edukasi
Not a member yet
4879 research outputs found
Sort by
Impulsive and Long Duration High-Energy Gamma-ray Emission From the Very Bright 2012 March 7 Solar Flares
No full textThe Fermi Large Area Telescope (LAT) observed two bright X-class solar ares on 2012 March 7, and detected gamma-rays up to 4 GeV. We detected gamma-rays both during the impulsive and temporally-extended emission phases, with emission above 100 MeV lasting for approximately 20 hours. Accurate localization of the gamma-ray production site(s) coincide with the solar active region from which X-ray emissions associated with these ares originated. Our analysis of the > 100 MeV gamma-ray emission shows a relatively rapid monotonic decrease in ux during the rst hour of the impulsive phase, and a much slower, almost monotonic decrease in ux for the next 20 hours. The spectra can be adequately described by a power law with a high energy exponential cuto , or as resulting from the decay of neutral pions produced by accelerated protons and ions with an isotropic power-law energy distribution. The required proton spectrum has a number index 3, with minor variations during the impulsive phase, while during the temporally extended phase the spectrum softens monotonically, starting with index 4. The > 30 MeV proton ux and spectra observed near the Earth by the GOES satellites also show a monotonic ux decrease and spectral softening during the extended phase, but with a harder spectrum, with index 3. Based on the Fermi -LAT and GOES observations of the ux and spectral evolution of these bright ares, we explore the relative merits of prompt and continuous acceleration scenarios, hadronic and leptonic emission processes, and acceleration at the solar corona by the fast Coronal Mass Ejections (CME) as explanations for the observations. We conclude that the most likely scenario is continuous acceleration of protons in the solar corona which penetrate the lower solar atmosphere and produce pions that decay into gamma-rays
Les 64 premières lignes du triangle de Pascal
No full textThe 64 first lines of the Pascal's Triangle (Les 64 premières lignes du triangle de Pascal
Une éponge pyramidale de Menger fractale obtenue à l'aide de la méthode des 'Iterated Function Systems' -IFS- fractal
No full textA fractal pyramidal Menger sponge computed by means of an 'Iterated Function System' -IFS- (Une éponge pyramidale de Menger fractale obtenue à l'aide de la méthode des 'Iterated Function Systems' -IFS- fractal
Second-order BSDEs with general reflection and game options under uncertainty
No full textInternational audienceThe aim of this paper is twofold. First, we extend the results of Matoussi et al. (2013) concerning the existence and uniqueness of second-order reflected 2BSDEs to the case of two obstacles. Under some regularity assumptions on one of the barriers, similar to the ones in Crépey and Matoussi (2008), and when the two barriers are completely separated, we provide a complete wellposedness theory for doubly reflected second-order BSDEs. We also show that these objects are related to non-standard optimal stopping games, thus generalizing the connection between DRBSDEs and Dynkin games first proved by Cvitanić and Karatzas (1996). More precisely, we show under a technical assumption that the second order DRBSDEs provide solutions of what we call uncertain Dynkin games and that they also allow us to obtain super and subhedging prices for American game options (also called Israeli options) in financial markets with volatility uncertainty
Redox-active phosphines: synthesis and crystal structures of palladium(II) complexes of a metallaphosphine in two different oxidation states.
No full textInternational audienceThe redox-active metallaphosphine [Fe(dppe)(η(5)-C5Me5)(C≡C-PPh2)] reacts with [Pd(1,5-cod)Cl2] to give mono- and bis-phosphine coordinated palladium centres as a function of stoichiometry, and these complexes provide a stable redox-active platform which allows reversible one-electron {Fe(II)→Fe(III)(+)} oxidations within the palladium coordination sphere
The MARs Boundary Layer Lidar Experiment: Mars Winds at last!
No full textMARBLL is an optical remote sensing in- strument using a mature state-of-the-art Doppler wind lidar technology specifically designed to operate at the surface of Mars. The instrument includes an emitting device (laser) and a spectral analyzer (Mach-Zehnder interferometer). Wind profiling is inferred from the 1064 nm beam emit- ted by the laser and subsequently backscattered to the telescope by the suspended aerosols. The received signal has a Doppler shift induced by the radial velocity component of the particles, which is quantified by the interferometer
Ti(OiPr)(4)/nBuLi: an attractive reagent system for [2+2+2] cyclotrimerisation reactions
No full textInternational audienceA convenient method for the [2+2+2] cyclotrimerisation of alkynes using Ti(OiPr)4/nBuLi is presented. Homotrimerisation of arylacetylenes proceeds within minutes with excellent regioselectivity. Moreover, the intermolecular construction of ABB heterotrimers can be achieved selectively from two different alkynes with similar electronic properties. The method is also suitable for the synthesis of pyridines
Measurement of the ttbar production cross section in pp collisions at sqrt(s)=8 TeV in dilepton final states containing one tau lepton
No full textSubmitted to Phys. Lett. B ; see paper for full list of authorsThe top-quark pair production cross section is measured in final states with one electron or muon and one hadronically decaying tau lepton from the process ttbar to (l nu[l]) (tau nu[tau]) bbbar, where l = e, mu. The data sample corresponds to an integrated luminosity of 19.6 inverse femtobarns collected with the CMS detector in proton-proton collisions at sqrt(s)=8 TeV. The measured cross section sigma[ttbar] = 257 +/- 3 (stat) +/- 24 (syst) +/- 7 (lum) pb, assuming a top-quark mass of 172.5 GeV, is consistent with the standard model prediction
On the Expressiveness of Intensional Communication
No full textInternational audienceThe expressiveness of communication primitives has been explored in a common framework based on the pi-calculus by considering four features: synchronism (asynchronous vs synchronous), arity (monadic vs polyadic data), communication medium (shared dataspaces vs channel-based), and pattern-matching (binding to a name vs testing name equality). Here pattern-matching is generalised to account for terms with internal structure such as in recent calculi like Spi calculi, Concurrent Pattern Calculus and Psi calculi. This paper explores intensionality upon terms, in particular communication primitives that can match upon both names and structures. By means of possibility/impossibility of encodings, this paper shows that intensionality alone can encode synchronism, arity, communication-medium, and pattern-matching, yet no combination of these without intensionality can encode any intensional language
Optimal control problems on stratifiable state constraints sets.
No full textParallel sessionInternational audienceWe consider an infinite horizon problem with state constraints K : inf Z 1 0 e t'(yx;u(t); u(t))dt u : [ 0 ;+1) ! A measurable yx;u(t) 2 K 8t 0 (P) : where > 0 is fixed and yx;u( ) is a trajectory of the control system ( y_ = f (y; u) a.e. t 0 y(0) = x 2 K We are mainly concerned with a characterization of the value function of (P) as the bilateral solution to a Hamilton-Jacobi-Bellman equation