9,001 research outputs found

    Geometric mutual information at classical critical points

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    A practical use of the entanglement entropy in a 1d quantum system is to identify the conformal field theory describing its critical behavior. It is exactly (c/3)ln⁡ℓ(c/3)\ln \ell for an interval of length ℓ\ell in an infinite system, where cc is the central charge of the conformal field theory. Here we define the geometric mutual information, an analogous quantity for classical critical points. We compute this for 2d conformal field theories in an arbitrary geometry, and show in particular that for a rectangle cut into two rectangles, it is proportional to cc. This makes it possible to extract cc in classical simulations, which we demonstrate for the critical Ising and 3-state Potts models.Comment: 5 pages. v3: published versio

    Microstructural modifications in tungsten induced by high flux plasma exposure : TEM examination

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    We have performed microstructural characterization using transmission electron microscopy (TEM) techniques to reveal nanometric features in the sub-surface region of tungsten samples exposed to high flux, low energy deuterium plasma. TEM examination revealed formation of a dense dislocation network and dislocation tangles, overall resulting in a strong increase in the dislocation density by at least one order of magnitude as compared to the initial one. Plasma-induced dislocation microstructure vanishes beyond a depth of about 10 mu m from the top of the exposed surface where the dislocation density and its morphology becomes comparable to the reference microstructure. Interstitial edge dislocation loops with Burgers vector a(0)/2 and a(0) were regularly observed within 6 mu m of the sub-surface region of the exposed samples, but absent in the reference material. The presence of these loops points to a co-existence of nanometric D bubbles, growing by loop punching mechanism, and sub-micron deuterium flakes, resulting in the formation of surface blisters, also observed here by scanning electron microscopy

    Advances concerning aliskiren, direct renin inhibitor and aliskiren-hydrochlorothiazide

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    peer reviewedL’aliskiren (RasilezÂź), inhibiteur direct de la rĂ©nine, est actuellement indiquĂ© dans le traitement de l’hypertension artĂ©rielle essentielle, en monothĂ©rapie ou en association, notamment avec l’hydrochlorothiazide (Rasilez HCTÂź). Il peut Ă©galement ĂȘtre utilisĂ© pour complĂ©ter le blocage du systĂšme rĂ©nine-angiotensine-aldostĂ©rone (SRAA) en combinaison avec un inhibiteur de l’enzyme de conversion de l’angiotensine (IEC) (ou Ă©ventuellement un antagoniste des rĂ©cepteurs AT1 ou ARA). Il reste, en effet, de la place pour des agents qui s’opposeraient encore mieux que les IEC ou les ARA Ă  la progression de la nĂ©phropathie diabĂ©tique. Dans ce contexte particulier, actuellement, le double blocage du SRAA offre probablement une meilleure possibilitĂ© de frein que le simple blocage, mais s’avĂšre ĂȘtre de manipulation plus dangereuse. L’aliskiren pourrait trouver une place privilĂ©giĂ©e pour optimiser le blocage du SRAA si les Ă©tudes en cours confirment les rĂ©sultats prĂ©liminaires favorables. Cet article rĂ©sume les donnĂ©es actualisĂ©es concernant les rĂ©percussions biochimiques du mode d’action spĂ©cifique de cette molĂ©cule, en particulier les interfĂ©rences possibles liĂ©es Ă  l’augmentation des taux de rĂ©nine/pro-rĂ©nine, ainsi que les rĂ©sultats des essais cliniques rĂ©cents, non seulement dans le domaine de l’hypertension artĂ©rielle, mais aussi du diabĂšte sucrĂ©, de l’insuffisance rĂ©nale et de la cardiologie. Les objectifs et les modalitĂ©s de rĂ©alisation de la grande Ă©tude de morbi-mortalitĂ© ALTITUDE seront aussi briĂšvement prĂ©sentĂ©s.Aliskiren (RasilezÂź), a direct renin inhibitor, is currently indicated for the treatment of essential hypertension, as monotherapy or in combination, especially with hydrochlorothiazide (Rasilez HCTÂź). It may also be use to obtain a more complete blockade of the renin-angiotensin-aldosterone system (RAAS) when it is associated with an angiotensin converting enzyme inhibitor (ACEI) (or an AT1 angiotensin receptor antagonist) (ARA). There is some room for agents that may be more efficacious in reducing the progression of diabetic nephropathy than ACEI or ARA. In this context, the dual blockade of RAAS most probably offers a better efficacy than the simple blockade, but also exposes to a higher risk. Should ongoing trials confirm the preliminary favourable results, aliskiren might reach a forefront position among the armamentarium now available to optimize the RAAS blockade. The present article will summarize advances concerning the biochemical effects of the specific mode of action of aliskiren, especially the potential interferences related to increased renin/pro-renin levels, as well as results of recent clinical trials, not only in hypertension, but also in the fields of diabetes, renal insufficiency and cardiology. The objectives and design of the landmark study ALTITUDE will also be briefly presented

    Developmental toxicity of combined ethylbenzene and methylethylketone administered by inhalation to rats

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    Pregnant Sprague–Dawley rats were exposed to ethylbenzene (EB; 0, 250, or 1000 ppm) and methylethylketone (MEK; 0, 1000, or 3000 ppm), alone and in combination, by inhalation, for 6 h/day, during days 6–20 of gestation. Maternal toxicity, evidenced by decreased in body weight gain and food consumption, tended to be greater after simultaneous exposures to the high concentrations of 1000 ppm EB and 3000 ppm MEK, when compared to the treatments with individual compounds. No significant increase in embryo/fetal lethality or incidence of malformations and variations was observed in any of the treatment groups. Fetal body weight was significantly reduced after individual treatment with 1000 ppm EB or 3000 ppm MEK, and in the combined groups. There was no evidence of interaction between EB and MEK in causing developmental toxicity

    Robust Adaptive Detection of Buried Pipes using GPR

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    International audienceDetection of buried objects such as pipes using a Ground Penetrating Radar (GPR) is intricate for three main reasons. First, noise is important in the resulting image because of the presence of several rocks and/or layers in the ground, highly influencing the Probability of False Alarm (PFA) level. Also, wave speed and object responses are unknown in the ground and depend on the relative permit-tivity, which is not directly measurable. Finally, the depth of the pipes leads to strong attenuation of the echoed signal, leading to poor SNR scenarios. In this paper, we propose a detection method: (1) enhancing the signal of interest while reducing the noise and layer contributions, and (2) giving a local estimate of the relative permittivity. We derive an adaptive detector where the signal of interest is parametrised by the wave speed in the ground. For this detector, noise is assumed to follow a Spherically Invariant Random Vector (SIRV) distribution in order to obtain a robust detection. We use robust maximum likelihood-type covariance matrix estimators called M-estimators. To handle the significant amount of data, we consider regularised versions of said estimators. Simulation will allow to estimate the relation PFA-Threshold. Comparison is performed with standard GPR processing methods, showing the aptitude of the method in detecting pipes having low response levels with a reasonable PFA

    Precursor-Directed Assembly of Complex Oxide Nanobeads: The Role of Strongly Coordinated Inorganic Anions

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    International audienceThe use of an inorganic perrhenate ligand in the structure of early-transition-metal alkoxide precursors permits to achieve uniform self-assembly of the primary nanoparticles produced by their hydrolysis. The latter has been carried out in a hydrocarbon reaction medium by the addition of water with vigorous stirring, either in the pure form or in solutions in parent alcohols. The self-assembly is guided by the surface charge enhanced by the presence of strongly coordinated anions as determined by zeta potential measurements. The aggregation process has been followed in real time by nanoparticle tracking analysis (Nano Sight technique). The reaction products are spherical aggregates with a size that can be efficiently controlled through the polarity of the reaction medium. The produced nanobeads have been characterized by TEM, SEM-EDS, DLS, nitrogen adsorption, and FTIR The coordination of metal centers has been investigated using EXAFS spectroscopy. The aggregates remain amorphous on thermal treatment of up to 700 degrees C (24 h treatment) but crystallin when treated at 1000 degrees C. This latter process is associated with the total loss of rhenium content and offers early-transition-metal oxides as products

    State estimation in quantum homodyne tomography with noisy data

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    In the framework of noisy quantum homodyne tomography with efficiency parameter 0<η≀10 < \eta \leq 1, we propose two estimators of a quantum state whose density matrix elements ρm,n\rho_{m,n} decrease like e−B(m+n)r/2e^{-B(m+n)^{r/ 2}}, for fixed known B>0B>0 and 0<r≀20<r\leq 2. The first procedure estimates the matrix coefficients by a projection method on the pattern functions (that we introduce here for 0<η≀1/20<\eta \leq 1/2), the second procedure is a kernel estimator of the associated Wigner function. We compute the convergence rates of these estimators, in L2\mathbb{L}_2 risk
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