Decoherence and gravitational backgrounds

We study the decoherence process associated with the scattering of stochastic gravitational waves. We discuss the case of macroscopic systems, such as the planetary motion of the Moon around the Earth, for which gravitational scattering is found to dominate decoherence though it has a negligible influence on damping. This contrast is due to the very high effective temperature of the background of gravitational waves in our galactic environment.Comment: 10 page

Quelles politiques de développement durable au Mali et à Madagascar ?

Ideas and values of "sustainable development" are transfered from the international to the national level in policy-making processes and give way to a recomposition of rural development policies : we study that policy transfert. In Mali and Madagascar, sustainable development policies are quite different. We give an interpretation of these differences by a comparative analysis of strategies of actors involved in policy-making processes. We show that these strategies are related to historical processes. In Mali and Madagascar, the long run analysis of agricultural and rural policy making allows us a better understanding of current sustainable development policies. ...French Abstract : Nous étudions le processus de transfert politique selon lequel les idées et valeurs du " développement durable ", mûries et véhiculées au niveau international, donnent lieu au niveau national à une recomposition des modes publics d'intervention en milieu rural. Au Mali et à Madagascar, les politiques de développement durable recouvrent des expressions différentes. Nous interprétons ces différences par une analyse comparative des stratégies des acteurs intervenant dans le jeu politique. Nous montrons que ces stratégies renvoient à des processus historiques. L'analyse sur le temps long des processus de construction et de mise en oeuvre des politiques agricoles et rurales dans ces pays permet de mieux comprendre les expressions qu'y revêt aujourd'hui le développement durable.POLICIES; RURAL DEVELOPMENT; SUSTAINABLE DEVELOPMENT; DEVELOPPEMENT RURAL; DEVELOPPEMENT DURABLE; MALI; MADAGASCAR

Parametric Self-Oscillation via Resonantly Enhanced Multiwave Mixing

We demonstrate an efficient nonlinear process in which Stokes and anti-Stokes components are generated spontaneously in a Raman-like, near resonant media driven by low power counter-propagating fields. Oscillation of this kind does not require optical cavity and can be viewed as a spontaneous formation of atomic coherence grating

Autofeedback scheme for preservation of macroscopic coherence in microwave cavities

We present a scheme for controlling the decoherence of a linear superposition of two coherent states with opposite phases in a high-Q microwave cavity, based on the injection of appropriately prepared ``probe'' and ``feedback'' Rydberg atoms, improving the one presented in [D. Vitali et al., Phys. Rev. Lett. 79, 2442 (1997)]. In the present scheme, the information transmission from the probe to the feedback atom is directly mediated by a second auxiliary cavity. The detection efficiency for the probe atom is no longer a critical parameter, and the decoherence time of the superposition state can be significantly increased using presently available technology.Comment: revtex, 15 pages, 4 eps figure

Self-Consistency Requirements of the Renormalization Group for Setting the Renormalization Scale

In conventional treatments, predictions from fixed-order perturbative QCD calculations cannot be fixed with certainty due to ambiguities in the choice of the renormalization scale as well as the renormalization scheme. In this paper we present a general discussion of the constraints of the renormalization group (RG) invariance on the choice of the renormalization scale. We adopt the RG based equations, which incorporate the scheme parameters, for a general exposition of RG invariance, since they simultaneously express the invariance of physical observables under both the variation of the renormalization scale and the renormalization scheme parameters. We then discuss the self-consistency requirements of the RG, such as reflexivity, symmetry, and transitivity, which must be satisfied by the scale-setting method. The Principle of Minimal Sensitivity (PMS) requires the slope of the approximant of an observable to vanish at the renormalization point. This criterion provides a scheme-independent estimation, but it violates the symmetry and transitivity properties of the RG and does not reproduce the Gell-Mann-Low scale for QED observables. The Principle of Maximum Conformality (PMC) satisfies all of the deductions of the RG invariance - reflectivity, symmetry, and transitivity. Using the PMC, all non-conformal $\{\beta^{\cal R}_i\}$-terms (${\cal R}$ stands for an arbitrary renormalization scheme) in the perturbative expansion series are summed into the running coupling, and one obtains a unique, scale-fixed, scheme-independent prediction at any finite order. The PMC scales and the resulting finite-order PMC predictions are both to high accuracy independent of the choice of initial renormalization scale, consistent with RG invariance. [...More in the text...]Comment: 15 pages, 4 figures. References updated. To be published in Phys.Rev.

Urinary metabolic profiles in early pregnancy are associated with preterm birth and fetal growth restriction in the Rhea mother-child cohort study

Syftet med studien var att undersöka vilka möjligheter matematikundervisning utomhus kan ge för elevernas utveckling och lärande. Syftet var även att undersöka hur utomhusmatematik kan användas som ett komplement till den traditionella inomhusundervisningen i ämnet matematik. Studien baserades på en kvalitativ forskningsansats där kvalitativa semistrukturerade intervjuer och ostrukturerade observationer användes som metoder för att besvara studiens forskningsfrågor. Sex lärare i F-3 intervjuades och två observationer på två olika skolor genomfördes. Resultatet visar att utomhusmatematiken kompletterar matematikundervisningen inomhus genom ett samspel mellan arbetssätt och miljöer. Resultatet visar även på flera positiva effekter med utomhusmatematik så som verklighetsanknytning, motivation, fysisk aktivitet, hälsa, sinnligt lärande, tillåtande miljö och sociala effekter.  De positiva effekter utomhusmatematiken medföljer för elevernas utveckling och lärande bör uppmärksamma fler lärare om dess möjligheter.

Investigation of intervertebral disc degeneration using multivariate FTIR spectroscopic imaging

Traditionally tissue samples are analysed using protein or enzyme specific stains on serial sections to build up a picture of the distribution of components contained within them. In this study we investigated the potential of multivariate curve resolution-alternating least squares (MCR-ALS) to deconvolute 2nd derivative spectra of Fourier transform infrared (FTIR) microscopic images measured in transflectance mode of goat and human paraffin embedded intervertebral disc (IVD) tissue sections, to see if this methodology can provide analogous information to that provided by immunohistochemical stains and bioassays but from a single section. MCR-ALS analysis of non-degenerate and enzymatically in vivo degenerated goat IVDs reveals five matrix components displaying distribution maps matching histological stains for collagen, elastin and proteoglycan (PG), as well as immunohistochemical stains for collagen type I and II. Interestingly, two components exhibiting characteristic spectral and distribution profiles of proteoglycans were found, and relative component/tissue maps of these components (labelled PG1 and PG2) showed distinct distributions in non-degenerate versus mildly degenerate goat samples. MCR-ALS analysis of human IVD sections resulted in comparable spectral profiles to those observed in the goat samples, highlighting the inter species transferability of the presented methodology. Multivariate FTIR image analysis of a set of 43 goat IVD sections allowed the extraction of semi-quantitative information from component/tissue gradients taken across the IVD width of collagen type I, collagen type II, PG1 and PG2. Regional component/tissue parameters were calculated and significant correlations were found between histological grades of degeneration and PG parameters (PG1: p = 0.0003, PG2: p < 0.0001); glycosaminoglycan (GAG) content and PGs (PG1: p = 0.0055, PG2: p = 0.0001); and MRI T2* measurements and PGs (PG1: p = 0.0021, PG2: p < 0.0001). Additionally, component/tissue parameters for collagen type I and II showed significant correlations with total collagen content (p = 0.0204, p = 0.0127). In conclusion, the presented findings illustrate, that the described multivariate FTIR imaging approach affords the necessary chemical specificity to be considered an important tool in the study of IVD degeneration in goat and human IVDs