SENEQUE: a multi-scaling GIS interface to the Riverstrahler model of the biogeochemical functioning of river systems

The Riverstrahler model describes the biogeochemical functioning of an entire river system, from 100 to 100,000 km(2) or more, taking into account the constraints set by the morphology of the drainage network, the meteorological/hydrological conditions, and the inputs of material from point and non-point sources in the watershed. This tool has been applied for research purpose to several river systems differing in terms of hydrological regime and anthropogenic influences. In order to improve its capabilities and its generic dimension, as well as to develop a user-friendly interface allowing its transfer to non-specialist users including managers, the model has been coupled to a GIS interface. This gives the user the possibility to visualize the available geospatial database, to select the best geographical representation of the drainage network, to automatically prepare the corresponding input files required for the model, to pilot the model calculation and to visualize the results. The coupling with a GIS interface has considerably improved the capabilities of the Riverstrahler model. The code of the model is now entirely generic and can be run on any river system for which a suitable database is available. Its spatial resolution can be adapted to the requirement of the relevant problem, from the highest level, where each elementary watershed is individualized, to the lower level, where the whole basin is idealized as one basin with tributaries of each order having the same characteristics. As an illustration of the new potentialities offered by the coupling of Riverstrahler with a GIS through the SENEQUE interface, the results of a same modeling scenario are compared at different spatial resolutions. For the first time, with on-line coupling to a geodatabase, the effect of increasing the spatial resolution of the drainage network representation on the performance of the Riverstrahler model has been examined. At the outlet of the basin, the water quality results were found invariant to a large degree, whatever the details of its representation in the calculations. This result justifies the use of a low resolution representation of the upstream watershed when results are required only at the outlet of the basin.     

Release of antimicrobial actives from microcapsules by the action of axillary bacteria

We describe the use of unique microcapsules that may be degraded by the actions of bacteria. These microcapsules are approximately 35 mum in diameter, are composed of natural protein, and may be filled with a variety of actives. We describe the use of antimicrobial actives such as farnesol and methylparaben to demonstrate that their release by the degradative actions of axillary bacteria such as Corynebacterium minutissimum, C. urealyticum, and Staphylococcus epidermidis leads to their demise. These microcapsules may be used in consumer products such as deodorants and antiperpirants that may, under actual use conditions, control malodor.     

Time Response to Irradiations of Tin Superheated Superconducting Grain Dispersions

We report a study of the time response to particle irradiations of superheated superconducting granule dispersions. This work, which complements a previous study of the magnetic field response to energy depositions, has been performed at 70mK with dispersions having volume filling factors up to 8.3%. In order to observe irradiation induced transitions, the applied magnetic field was ramped up and stabilized at different pause field values. During pauses, the measured transition rates decay in time and are found not to be affected by magnetostatic inter-grains interactions. On this basis, we elaborate a model of time response for a set of isolated grains which assumes that normal state nucleation results from adiabatic and homogeneous heating of full granule volumes (calorimetric response). The analysis of experimental results allows the identification of two different types of time response which we correlate to the way the initial energy deposition nucleates the normal state. Most of the time, transitions result from calorimetric responses: as described by the proposed model, the proximity between the pause field and the transition field of a granule uniquely defines its probability of transition. Its value is shown to be determined by the spectroscopic characteristics of the radioactive source. Less often, nucleation of the normal state occurs before the heat is homogeneously distributed within the granule volume. In this case, the transition probability also depends on the interval separating the pause field and the superheating limit.     

The overlapping contributions of attachment orientation and social support in predicting life-events distress.

Attachment anxiety, attachment avoidance, and perceived social support are examined as predictors of life-events distress. Clients at initial intake to an addiction treatment centre and university students in their graduating year were administered measures of attachment orientation, social support, and the experience of distressing life events. Hypotheses were tested across different categories of distressing life events (overall distress, bereavement, relationship dissolution, crime victimization, and severe accidents). We found that attachment anxiety and attachment avoidance have varying predictive utility for distress, depending on the type of event. Social support did not account for variance beyond attachment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attachment, motivations, and alcohol: Testing a dual-path model of high-risk drinking and adverse consequences in transitional clinical and student samples.

The purpose of this study was to replicate and extend a motivational model of high-risk drinking and alcohol-related consequences (Cooper, Frone, Russell, & Mudar, 1995; Read, Wood, Kahler, Maddock, & Palfai, 2003), testing the notion that attachment is a common antecedent for both the affective and social paths to problem drinking, defined in terms of 2 dimensions; high-risk drinking and alcohol-related consequences. First-year university students (N = 696), and first-time clients at an addiction treatment facility (N = 213) completed questionnaires assessing alcohol use, alcohol-related consequences, drinking motives, and attachment style. Results underscored the importance of the affective path to drinking patterns and to vulnerability to problems. Results also found that those with higher levels of attachment anxiety were more vulnerable to experiencing adverse consequences related to their drinking. These findings emphasise the importance of attachment styles as a risk factor for high-risk drinking and experiencing alcohol-related consequences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of support on the apparent activity of palladium oxide in catalytic methane combustion

The support effect on the low temperature catalytic oxidation of methane over palladium catalysts was studied by comparing a series of metal oxides as the support. Samples of 0.010 g/g Pd catalysts supported on different grades and/or phases of TiO₂, Al₂O₃, and ZrO₂ were prepared via incipient impregnation and their catalytic activity was evaluated using a laboratory plug-flow reactor. The specific surface area of the supports determined by nitrogen adsorption varied from about 13-220 m²/g. Initial experiments conducted with titania (anatase) as a support showed a low apparent activity and a poor thermal stability. Focusing on anatase, we have successfully improved its thermal stability by additions of Al₂O₃ or by doping with CeO₂, or La₂O₃. However, contrary to expectations based on some information in the literature, we have found that the activity decreased in the sequence of Al₂O₃ > ZrO₂ > TiO₂, and was not a direct function of specific surface area. This was especially evident in the case of titania. The surface structure of the support and the nature of its interaction with the active component PdO seem to play a far more important role in activity than the apparent specific surface area. Moreover, anatase-supported catalysts present a very rapid deactivation, whereas rutile-supported catalysts are relatively stable. The observed phenomena could potentially be related to the interaction between support and the active phase of palladium. Several models have been proposed to describe the strong metal-support interaction, but either charge transfer or encapsulation seems to be the most probable.     

Nitrate leaching from organic and conventional arable crop farms in the Seine Basin (France)

In the Seine Basin, characterised by intensive arable crops, most of the surface and groundwater is contaminated by nitrate (NO₃ ^?). The goal of this study is to investigate nitrogen leaching on commercial arable crop farms in five organic and three conventional systems. In 2012–2013, a total of 37 fields are studied on eight arable crop rotations, for three different soil and climate conditions. Our results show a gradient of soil solution concentrations in function of crops, lower for alfalfa (mean 2.8 mg NO₃-N l^?1) and higher for crops fertilised after legumes (15 mg NO₃-N l^?1). Catch crops decrease nitrate soil solution concentrations, below 10 mg NO₃-N l^?1. For a full rotation, the estimated mean concentrations is lower for organic farming, 12 ± 5 mg NO₃-N l^?1 than for conventional farming 24 ± 11 mg NO₃-N l^?1, with however a large range of variability. Overall, organic farming shows lower leaching rates (14–50 kg NO₃-N ha^?1) than conventional farms (32–77 kg NO₃-N ha^?1). Taking into account the slightly lower productivity of organic systems, we show that yield-scaled leaching values are also lower for organic (0.2 ± 0.1 kg N kg^?1 N year^?1) than for conventional systems (0.3 ± 0.1 kg N kg^?1 N year^?1). Overall, we show that organic farming systems have lower impact than conventional farming on N leaching, although there is still room for progress in both systems in commercial farms.     

Quantitative analysis of vitamin A degradation by Raman spectroscopy

Vitamin A is known to support cell growth promotion, maintenance, and differentiation of epithelial tissues. Retinol is currently used in cosmetic formulations and products to deliver these and other benefits to the skin. However, retinol is known to be unstable and, therefore, remains of great concern to the cosmetic industry. The decomposition pathways of the retinoids in general have been previously postulated and investigated mostly by high-performance liquid chromatography (HPLC) with UV/Vis spectroscopy. In our studies, we examined specific conditions at which retinol degrades and subsequently identified and quantified the products of retinol decomposition by Raman spectroscopy. We reveal which experimental settings and computational tools allow monitoring of in situ evolution of an all-trans retinol solution when submitted to UV light in the presence of oxygen.     

An optimized method for intensive screening of molecules that stimulate beta-defensin 2 or 3 (hBD2 or hBD3) expression in cultured normal human keratinocytes

Normal human skin controls the intrusion of microorganisms by the production of peptide antibiotics such as defensins. The aim of our study was to develop a culture model of normal human keratinocytes for optimal beta-defensin mRNA detection which allows the screening of molecules able to stimulate hBD2 and hBD3 without inducing pro-inflammatory cytokines. A keratinocyte culture model in 96-well plates, in high calcium medium (1.7 mm) allowed to analyze hBD2 and hBD3 mRNA expression in basal condition and after cell stimulation by products from diverse vegetal extracts. The release of IL-8 and the chemokine MIP-3alpha was also evaluated in cell supernatants by ELISA. Among the 184 extracts tested, 75 showed a stimulatory effect on beta-defensin expression: 40 on hBD2, 26 on hBD3 and nine on both defensins. Fifteen of these substances which also induced the release of pro-inflammatory cytokines were eliminated. Among the other substances, four were selected and were analyzed in a dose-dependent study (n = 4) by real-time quantitative RT-PCR and completed by a measure of MIP-3alpha, IL-8 and IL-1alpha levels. These data underline the important necessity of screening result controls by a quantitative method reproduced at least three times. This new method of intensive screening allowed us to exhibit vegetal extracts that were able to stimulate epidermal beta-defensin expression without inducing an up-secretion of pro-inflammatory cytokines.