Using betweenness metrics to investigate the geographical distribution of retailers

In retailing, the spatial distribution of other stores and consumers drives the location’s accessibility and attractiveness. In particular, the literature shows that a place is more attractive for retailers if the generic routes taken by consumers often cross it. However, previous studies failed to consider that there are at least two possible consumer routes: job commutes from residential to work places and shopping trips among stores. In this paper, we analyze the impact of both consumer routes on the commercial patterns in Turin. The paper demonstrates that daily commutes to workplaces do not benefit a retailer along the trip, as much as journeys for shopping purposes do. In particular, we show that the benefits that a store can have when localized on the routes depend on the kind of goods it sells. Finally, the paper shows that stores selling homogeneous products and stores selling comparable goods can differently benefit from being located in population hotspots and in commercial areas

High-voltage 10 ns delayed paired or bipolar pulses for in vitro bioelectric experiments

International audienc

Characterisation of iron (II) sulfides in wet archaeological woods: the wreck of Mandirac (IV th century, antique ports of Narbonne, France)

International audienceThe wreck of Mandirac (Narbonne, France, IV century) was excavated in 2013 and 2014 from waterlogged soil. A magnetic prospection campaign performed in 2014 revealed that the wood was abnormally magnetic. A plank extracted from the hull, containing an iron nail, was analysed using Environmental Scanning Electron Microscopy, micro-Raman spectroscopy, X-Ray diffraction and magnetic characterization methods in order to identify the mineral composition inside the wood and of the nail. Results revealed an accumulation of greigite and pyrite in the wood around the nail, where the pH was measured below 3. The nail was completely corroded into pyrite and siderite, with no metal left. Marcasite was also identified far from the nail, where the pH was measured around 5. Greigite was the only phase responsible of the magnetic signal emitted from the wood and proved to be present in varying amounts throughout the entire wreck. The iron sulfides were probably formed via anaerobic sulphidogenic bacteria influenced corrosion processes, which occurred on the nails. These results are very different from those obtained from more recent shipwrecks (XIX century). So the nature of these iron sulfides in wet archaeological woods is discussed

Assemblages bois-fer et biocorrosion : étude des sulfures de fer formés en conditions anoxiques dans des bois d'épaves

International audienceLes conséquences de la corrosion des renforts de fer dans les assemblages de bois peuvent compromettre la durabilité d'une structure. Si le bois est gorgé d'eau, les conditions à la surface du métal deviennent anoxiques. La présence de fer et l'activité microbiologique favorisée par la présence de matière organique font des systèmes composites bois-fer des milieux propices à l'apparition de sulfures de fer. Or ces derniers se transforment soit en milieux anaérobies sulfurés, soit lorsque l'oxygène diffuse dans le bois, soit lors d'une remise à l'air de la structure, avec pour conséquence de contribuer à la dégradation du bois. Afin de mieux comprendre les mécanismes impliqués, nous étudions des bois d'épaves archéologiques. Cet article sera illustré par des exemples d'époques récentes (18 è s. 19 è s.) et antiques et par une approche analytique multi-techniques originale. La mackinawite, la greigite et la pyrite ont été identifiées et il semble que la nature des sulfures de fer présents soit liée à l'âge du vestige conformément aux schémas proposés dans la littérature d'évolution de ces composés. La greigite est intéressante à considérer. Seule phase détectée quel que soit l’âge, elle peut s’avérer un bon marqueur de la biocorrosion du fer dans les assemblages bois-fer

Ecotoxicity tests and ecoscores to improve soil management : case of a secondary lead smelter plant

International audienceriginally located on the outskirts of cities, numerous industrial sites, sometimes abandoned, are now in urban areas and are therefore likely to have environmental and health risks to surrounding populations. Currently, rehabilitation of the sites frequently entails excavation of polluted soils. Excavated soils can thus follow two different ways: landfilling, expensive and energy intensive, or reuse/recycling, integrated to sustainable development. The choice of a specific track mainly depends on total and leachable concentrations of the pollutant in the soil. Among the numerous pollutants observed in urban and peri-urban areas, trace metals are often present in soils; atmosphere emissions by smelters being one of the main anthropogenic source. MTE speciation and compartmentalization in soils can modify their impact on living organisms

Ecotoxicity tests and ecoscores to improve soil management : case of a secondary lead smelter plant

International audienceriginally located on the outskirts of cities, numerous industrial sites, sometimes abandoned, are now in urban areas and are therefore likely to have environmental and health risks to surrounding populations. Currently, rehabilitation of the sites frequently entails excavation of polluted soils. Excavated soils can thus follow two different ways: landfilling, expensive and energy intensive, or reuse/recycling, integrated to sustainable development. The choice of a specific track mainly depends on total and leachable concentrations of the pollutant in the soil. Among the numerous pollutants observed in urban and peri-urban areas, trace metals are often present in soils; atmosphere emissions by smelters being one of the main anthropogenic source. MTE speciation and compartmentalization in soils can modify their impact on living organisms

Picosecond polarized supercontinuum generation controlled by intermodal four-wave mixing for fluorescence lifetime imaging microscopy

International audienceWe present the generation of a picosecond polarized supercontinuum in highly birefringent multimodal microstructured fiber. The initial steps of the spectral broadening are dominated by intermodal four-wave mixing controlled by the specific fiber design. Using a low repetition rate ultra-stable solid state laser, a pulse train well-suited for versatile time-domain fluorescence lifetime imaging applications is obtaine

Characterization and regulation of the expression of scyllatoxin (Leiurotoxin I) receptors in the human neuroblastoma cell line NB-OK 1

Abstract125I-[Tyr2]scyllatoxin allowed to label a single class of high-affinity receptors in membranes from the human neuroblastoma cell line NB-OK 1. The Kd of these receptors was 60 pM for scyllatoxin (Leiurotoxin I) and 20 pM for apamin and the Bmax was low (3.8 fmol/mg membrane protein). K+ increased toxin binding at low concentrations but exerted opposite effects at high concentrations. Ca2+, guanidinium and Na+ exerted only inhibitory effects on binding. Scyllatoxin binding sites were overexpressed 2.5-fold after a 24-h cell pretreatment with 2 mM butyrate. This effect was suppressed by cycloheximide

Comparative study between radiofrequency-induced and muscimol-induced inhibition of cultured networks of cortical neuron

Previous studies have shown that spontaneously active cultured networks of cortical neuron grown planar microelectrode arrays are sensitive to radiofrequency (RF) fields and exhibit an inhibitory response more pronounced as the exposure time and power increase. To better understand the mechanism behind the observed effects, we aimed at identifying similarities and differences between the inhibitory effect of RF fields (continuous wave, 1800 MHz) to the γ-aminobutyric acid type A (GABAA) receptor agonist muscimol (MU). Inhibition of the network bursting activity in response to RF exposure became apparent at an SAR level of 28.6 W/kg and co-occurred with an elevation of the culture medium temperature of ~1°C. Exposure to RF fields preferentially inhibits bursting over spiking activity and exerts fewer constraints on neural network bursting synchrony, differentiating it from a pharmacological inhibition with MU. Network rebound excitation, a phenomenon relying on the intrinsic properties of cortical neurons, was observed following the removal of tonic hyperpolarization after washout of MU but not in response to cessation of RF exposure. This implies that hyperpolarization is not the main driving force mediating the inhibitory effects of RF fields. At the level of single neurons, network inhibition induced by MU and RF fields occurred with reduced action potential (AP) half-width. As changes in AP waveform strongly influence efficacy of synaptic transmission, the narrowing effect on AP seen under RF exposure might contribute to reducing network bursting activity. By pointing only to a partial overlap between the inhibitory hallmarks of these two forms of inhibition, our data suggest that the inhibitory mechanisms of the action of RF fields differ from the ones mediated by the activation of GABAA receptors