Electrical Storms in Brugada Syndrome: Review of Pharmacologic and Ablative Therapeutic Options

Electrical storm occurring in a patient with the Brugada syndrome is an exceptional but malignant and potentially lethal event. Efficient therapeutic solutions should be known and urgently applied because of the inability of usual antiarrhythmic means in preventing multiple recurrences of ventricular arrhythmias. Isoproterenol should be immediately infused while oral quinidine should be further administrated when isoproterenol is not effective. In case of failure of these therapeutic options, ablation of the triggering ventricular ectopies should be attempte

Determinants of Productivity per Employee: an Empirical Estimation Using Panel Data

Two different approaches are used in this article to study productivity per employee: the determinants of its growth rate in the 1990s are first examined, and then the determinants of its level, using a more structural approach. ICT are shown to have a positive and significant effect on both growth rates and levels of productivity. This result is consistent with that of Gust and Marquez (2002), although the sample of countries is larger and GMM are used. In both sections of the paper, the employment rate and productivity exhibit a significant negative relationship, arising from the concentration of employment on the most productive members of the workforce. Indicators of financial depth and price stability are found to be significant.Productivity ; Panel ; Generalized method of moments ; Information and communication technology (ICT) ; Growth accounting

The Breaks in per Capita Productivity Trends in a Number of Industrial Countries

The purpose of this article is to study the trends in per capita productivity in several major industrialised countries. The analysis is first based on annual data over a long period spanning the entire 20th century for the United States, France and the United Kingdom. Productivity trends are then studied over a shorter period, using quarterly data, for the United States, France, the United Kingdom, Germany, Spain, Japan and the Netherlands. There are already a large number of studies of this kind, but they are too often focused on presenting average productivity growth rates for given periods chosen on an ad hoc basis. In this article, we use a robust statistical method to endogenously identify possible breaks in per capita productivity trends. This method, developed by Bai and Perron (1998), brings out the following salient features: – in the United States, per capita productivity growth accelerated following the trend break at the start of the 1920s, then slowed down at the end of the 1960s. This finding is in line with the “Big Wave” concept developed by Gordon (1999, 2002) to describe the trends in US productivity growth throughout the 20 th century. – French and UK productivity started catching up with that in the United States around the end of the Second World War. – Most of the countries under review recorded slower trend productivity growth in the first half of the 1970s. In the United States, this break occurred in 1966. This finding differs from that of other existing analyses, which point to 1974. – Trend productivity growth in Europe and Japan slowed in the 1990s, whereas US productivity gained momentum over the same period.Productivity trends ; Structural breaks ; Bai and Perron method

Casimir-Polder induced Rabi oscillations

We show that the Casimir-Polder interaction may induce coherent oscillations between degenerate atomic states. We illustrate this effect by computing the Casimir-Polder induced Rabi frequency on a $^{87}$Rb atom as it interacts with a reflecting surface. The atom oscillates between two Zeeman sublevels of its ground state undergoing a periodic exchange of angular momentum with the vacuum photons.Comment: minor corrections made to agree with the published versio

Investigation of the thermal stability of Mg/Co periodic multilayers for EUV applications

We present the results of the characterization of Mg/Co periodic multilayers and their thermal stability for the EUV range. The annealing study is performed up to a temperature of 400\degree C. Images obtained by scanning transmission electron microscopy and electron energy loss spectroscopy clearly show the good quality of the multilayer structure. The measurements of the EUV reflectivity around 25 nm (~49 eV) indicate that the reflectivity decreases when the annealing temperature increases above 300\degreeC. X-ray emission spectroscopy is performed to determine the chemical state of the Mg atoms within the Mg/Co multilayer. Nuclear magnetic resonance used to determine the chemical state of the Co atoms and scanning electron microscopy images of cross sections of the Mg/Co multilayers reveal changes in the morphology of the stack from an annealing temperature of 305\degreee;C. This explains the observed reflectivity loss.Comment: Published in Applied Physics A: Materials Science \& Processing Published at http://www.springerlink.com.chimie.gate.inist.fr/content/6v396j6m56771r61/ 21 page

Formation of the compact jets in the black hole GX 339-4

Galactic black hole binaries produce powerful outflows with emit over almost the entire electromagnetic spectrum. Here, we report the first detection with the Herschel observatory of a variable far-infrared source associated with the compact jets of the black hole transient GX 339-4 during the decay of its recent 2010-2011 outburst, after the transition to the hard state. We also outline the results of very sensitive radio observations conducted with the Australia Telescope Compact Array, along with a series of near-infrared, optical (OIR) and X-ray observations, allowing for the first time the re-ignition of the compact jets to be observed over a wide range of wavelengths. The compact jets first turn on at radio frequencies with an optically thin spectrum that later evolves to optically thick synchrotron emission. An OIR reflare is observed about ten days after the onset of radio and hard X-ray emission, likely reflecting the necessary time to build up enough density, as well as to have acceleration (e.g. through shocks) along an extended region in the jets. The Herschel measurements are consistent with an extrapolation of the radio inverted power-law spectrum, but they highlight a more complex radio to OIR spectral energy distribution for the jets.Comment: Accepted for publication in MNRAS Letter, 6 pages, 3 Figures + 1 online Tabl

Hyperspectral imaging to characterize table grapes

Table grape quality is of importance for consumers and thus for producers. Its objective quality is usually determined by destructive methods mainly based on sugar content. This study proposed to evaluate the possibility of hyperspectral imaging to characterize table grapes quality through its sugar (TSS), total flavonoid (TF), and total anthocyanin (TA) contents. Different data pretreatments (WD, SNV, and 1st and 2nd derivative) and different methods were tested to get the best prediction models: PLS with full spectra and then Multiple Linear Regression (MLR) were realized after selecting the optimal wavelengths thanks to the regression coefficients (coefficients) and the Variable Importance in Projection (VIP) scores. All models were good at showing that hyperspectral imaging is a relevant method to predict sugar, total flavonoid, and total anthocyanin contents. The best predictions were obtained from optimal wavelength selection based on coefficients for TSS and from VIPs optimal wavelength windows using SNV pre-treatment for total flavonoid and total anthocyanin content. Thus, good prediction models were proposed in order to characterize grapes while reducing the data sets and limit the data storage to enable an industrial use

Spectral analysis of Gene co-expression network of Zebrafish

We analyze the gene expression data of Zebrafish under the combined framework of complex networks and random matrix theory. The nearest neighbor spacing distribution of the corresponding matrix spectra follows random matrix predictions of Gaussian orthogonal statistics. Based on the eigenvector analysis we can divide the spectra into two parts, first part for which the eigenvector localization properties match with the random matrix theory predictions, and the second part for which they show deviation from the theory and hence are useful to understand the system dependent properties. Spectra with the localized eigenvectors can be characterized into three groups based on the eigenvalues. We explore the position of localized nodes from these different categories. Using an overlap measure, we find that the top contributing nodes in the different groups carry distinguished structural features. Furthermore, the top contributing nodes of the different localized eigenvectors corresponding to the lower eigenvalue regime form different densely connected structure well separated from each other. Preliminary biological interpretation of the genes, associated with the top contributing nodes in the localized eigenvectors, suggests that the genes corresponding to same vector share common features.Comment: 6 pages, four figures (accepted in EPL