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We investigate the statistical properties of votes of customers for spots of France collected by the startup company Nomao. The frequencies of votes per spot and per customer are characterized by a power law distribution which remains stable on a time scale of a decade when the number of votes is varied by almost two orders of magnitude. Using the computer science methods we explore the spectrum and the eigenvalues of a matrix containing user ratings to geolocalized items. Eigenvalues nicely map to large towns and regions but show certain level of instability as we modify the interpretation of the underlying matrix. We evaluate imputation strategies that provide improved prediction performance by reaching geographically smooth eigenvectors. We point on possible links between distribution of votes and the phenomenon of self-organized criticality. [ABSTRACT FROM AUTHOR]

Hadron physics represents the study of strongly interacting matter in all its manifestations and understanding its properties and interactions. The interest in this field has been revitalized by the discovery of new light hadrons, charmonium- and bottomonium-like states. In this paper, the most recent experimental results from different experiments are reviewed. [ABSTRACT FROM AUTHOR]

Abundances of europium for 112 FGK dwarf stars of thick and thin disks have been determined in the metallicity range of −1.0 < [Fe/H] < +0.3. Spectra of the studied stars have been obtained using the 1.93-m telescope of Haute-Provence Observatory (France) with spectral resolution R = 42000 and signal-to-noise ratio S/N = 100−300. Eu content has been calculated with assumption of LTE using the synthetic spectrum approach with detailed consideration of superfine structure. Analysis of europium abundances as a function of metallicity in kinematically selected stars of the Galactic thick and thin disks revealed different values in the disks. Comparison of europium abundances with magnesium abundances makes it possible to assume that at [Fe/H] < −0.2 dex the origins of these elements are similar and at [Fe/H] > −0.2 dex they are, probably, different. [ABSTRACT FROM AUTHOR]

The article discusses the technical aspects of the reflectometer device which was made by the French Atomic Energy Commission (CEA). The study found that the reflectance measurements of the device with eight ball bearings in different diameters have a wide range in checking the authenticity of the measure depending on the curvature radius of the measuring system. Information regarding how the reflectance and signals operate in the spherical components using spectroscopy is also elaborated.

The H/V spectral ratio method based on seismic noise (HVSRN) was used in the Grenoble Basin (France), an Alpine valley characterized by a small apex ratio. The resonance frequencies obtained in the experiments were compared to the thickness of the sediments deduced from a microgravimetric survey and to the 1-D theoretical assessment of site responses. Given the abundance of data on the sediments and depth of the basin, the values of the theoretical resonance frequency f o can be determined quite accurately. However, it has been observed that the effects of basin geometry can disturb f o measurements using the HVSR method, in particular for a case like the Grenoble Basin, which has a small apex ratio (w/H) and strong suspected 2-D and/or 3-D effects. Interpretation of f o values in terms of bedrock depth gives rise to estimation errors of about 10% in certain cases, with the most significant errors (>50%) occurring on the edges of the basin, where subsurface layers are characterised by larger heterogeneities and where the basin topography is accentuated. This study suggests that great care must be taken when using the HVSRN method as an exploration tool, at least in valleys with a small apex ratio. [ABSTRACT FROM AUTHOR]

The article discusses the study regarding the phototransformation of 2-chloroaniline in aqueous solution, in France. The study is aimed to analyze the main photoproducts formed in aqueous solution, and to compare them with the photochemical behaviors previously published. An evaluation of the pKa from the protonated form of 2-chloroaniline was made at 2.6 from the variation of UV spectrum with pH. It was observed that after irradiation of 1 minute, in which after about 22 percent conversion, the solution was brownish, but only one main product could be observed on the HPLC chromatogram. Therefore, it was concluded that 2-chloroaniline behaves as a 2-chlorophenolate that leads to a photocontraction of the ring, in aqueous solution.

The article reports on the powerful nuclear magnetic resonance (NMR) spectroscopy developed by the European Centre for High Field NMR (CRMN) in Lyon, France. It features the optimism of CRMN scientific director Lyndon Emsley on the potential of the machine to attract the interest of chemists and structural biologists. It compares NMR spectroscopy with X-ray crystallography. It also presents the insights by biochemist Charles Sanders on the utilization of the machine in determining the structure of a large membrane protein, and by Imperial College's Jeremy Nicholson on the medical application of NMR spectroscopy. Moreover, it also looks into the significance of the machine for metabolic profiling.

Information about several papers discussed at the Sixth International Conference on tunable diode laser spectroscopy that was held in Reims, France on July 9-13, 2007 is presented. The conference include the presentation by Manfred Zendel of the International Atomic Energy Agency (IAEA) entitled "Challenges and Technology Needs" and that of Natacha Peter concerning the applicability of tunable diode laser spectroscopy in addressing international safeguards.