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( R )‐α‐Trifluoromethylalanine as a 19 F NMR Probe for the Monitoring of Protease Digestion of Peptides
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Le statut de réfugié à titre dérivé de l'enfant mineur devant la CJUE
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The gas-phase abundance of sulfur in dense cores
No full textInternational audienceThe abundance of volatile sulfur in dense clouds is an old problem in studies of the physics and chemistry of star forming regions. Sulfur is an important species because its low ionization potential makes it a potentially important charge carrier. Observed sulfur-bearing species in the gas-phase of dense clouds represent only a minor fraction of the cosmic sulfur abundance, which has been interpreted as a signature of sulfur depletion into ices at the surface of dust grains. Yet, atomic sulfur, which could be the main gas-phase carrier, can not be observed directly in cold cores. We present measurements of the NS radical toward four dense cores performed with the IRAM-30m telescope. Analytical chemical considerations and chemical models over a wide parameter space show that the NS:N2H+ abundance ratio provides a direct constraint on the abundance of gas-phase atomic sulfur. Toward early-type cores, we find that n(S)/n H is close, or even equal, to the cosmic abundance of sulfur, 14×10−6 , demonstrating that sulfur is not depleted and is atomic, in agreement with chemical models. More chemically evolved cores show sulfur depletion by factors up to 100 in their densest parts. In L1544, atomic sulfur depletion is shown to increase with increasing density. Future observations are needed to discover the solid-phase carrier of sulfur. The initial steps of the collapse of pre-stellar cores in the high sulfur abundance regime will also need to be explored from chemical and dynamical perspectives
Harmonic dual dressing of spin-1/2 systems
No full textInternational audienceControlled modifications of the magnetic response of a two-level system are produced in dressed systems by one high-frequency, strong, and nonresonant electromagnetic field. This quantum control is greatly enhanced and enriched by a harmonic, commensurable, and orthogonally oriented dual dressing, as discussed here. The secondary field enables a fine tuning of the qubit response, with control parameter amplitude, harmonic content, spatial orientation, and phase relation. Our analysis, mainly based on a perturbative approach with respect to the driving strength, includes also nonperturbative numerical solutions. The Zeeman response becomes anisotropic in a triaxial geometry and includes a nonlinear quadratic contribution. The long-time dynamics is described by an anisotropic effective magnetic field representing the handle for the system full engineering. Through the low-order harmonic mixing, the bichromatic driving generates a synthetic static field modifying the system dynamics. The spin temporal evolution includes a micromotion at harmonics of the driving frequency whose role in the spin detection is examined. Our dressing increases the two-level energy splitting, improving the spin detection sensitivity. In the weak-field direction it compensates the static fields applied in different geometries. The results presented here lay a foundation for additional applications to be harnessed in quantum simulations
Sharp decay rate for the damped wave equations with convex-shaped damping
No full textInternational audienceWe revisit the damped wave equation on two-dimensional torus where the damped region does not satisfy the geometric control condition. We show that if the damping vanishes as a Hölder function |x| β , and in addition, the boundary of the damped region is strictly convex, the wave is stable at rate t −1+ 2 2β+7 , which is better than the known optimal decay rate t −1+ 1 β+3 for strip-shaped dampings of the same Hölder regularity.Moreover, we show by example that the decay rate is optimal. This illustrates the fact that the sharp energy decay rate depends not only on the order of vanishing of the damping, but also on the shape of the damped region The main ingredient of the proof is the averaging method (normal form reduction) developed by Hitrick and Sjöstrand ([Hi1][Sj])
Facts Versus Falsehoods: Decoding the Gandhi-Bose Relationship
No full textIndian History vehemently celebrates two particular days of the Year: 26th January and 15th August. One is Republic Day, wherein the coveted Indian Constitution was enforced: the other is Independence Day (when the country was liberated from prolonged colonial rule). The literature surrounding the Indian National Struggle particularly focuses on a few selected leaders such as Mahatma Gandhi, Jawaharlal Nehru, Sardar Vallabhai Patel, Dr. B.R. Ambedkar, and others. Although some texts and civil society groups categorically shift the focus on others who also have contributed to the movement, these ‘others’ have so far been overlooked and most likely forgotten due to the several private interests at stake. One such forgotten leader is Subhas Chandra Bose, often referred as Netaji by his followers. This article intends to highlight Bose’s role in Indian History and uncover his relationship with Gandhi, the Father of the Nation
"Eine Nation, ein Volk, eine Kultur." Ideologie und Politik des Hindunationalismus in Indien
Get PDFSeit 2014 regiert in Indien die hindunationale Bharatiya Janata Party (Indische Volkspartei, BJP). Bereits von 1998 bis 2004 führte sie eine Regierungskoalition an. Dieser Aufstieg zur Macht setzte Ende der 1980er-Jahre ein und erreichte bei den letzten Wahlen 2019 seinen vorläufigen Höhepunkt. Ihm entspricht der Abstieg des ehemals mächtigen Indian National Congress, der Indien jahrzehntelang dominiert hatte. Der Weg der BJP zur Macht wurde begleitet von zahlreichen gewaltsamen Auseinandersetzungen zwischen der Mehrheit der Hindus (80 % der Bevölkerung) und den Minderheiten der Muslime (14 %) und der Christen (2,3 %)
On computing evidential centroid through conjunctive combination: an impossibility theorem
No full textInternational audienceThe theory of belief functions (TBF) is now a widespread framework to deal and reason with uncertain and imprecise information, in particular to solve information fusion and clustering problems. Combination functions (rules) and distances are essential tools common to both the clustering and information fusion problems in the context of TBF, which have generated considerable literature. Distances and combination between evidence corpus of TBF are indeed often used within various clustering and classification algorithms, however their interplay and connections have seldom been investigated, which is the topic of this paper. More precisely, we focus on the problem of aggregating evidence corpus to obtain a representative one, and we show through an impossibility theorem that in this case, there is a fundamental contradiction between the use of conjunctive combination rules on the one hand, and the use of distances on the other hand. Rather than adding new methodologies, such results are instrumental in guiding the user among the many methodologies that already exist. To illustrate the interest of our results, we discuss different cases where they are at play. Impact Statement-Within the theory of belief functions, both distances and conjunctive combination rules can be used to achieve very similar purposes: evaluating the conflict between sources, performing supervised or unsupervised learning in presence of evidential information, or more simply obtaining a synthetic representation of multiple items of information. However, the results obtained by both approaches may show some inconsistency between them. This paper provides some insight as to why this may happen, showing that the two approaches are definitely at odds, and that using distances is, for instance, incompatible with some fundamental notions of the theory of belief functions, such as the least commitment principle. We illustrate the importance of the studied differences on problems such as k-centroid clustering, and discuss the importance of interpretations in such problems, which is rarely done in the literature