Modeling of the Electrochemical Reactions at the Electrode-Electrolyte Interface of Nickel/Metal Hydride Batteries by an Equivalent Electrical Circuit

Based on the experimental impedance spectra, the electrochemical reactions that are deposed at the electrode-electrolyte interface can be modeled by equivalent electrical circuits. Each element used in the circuit must have a physical correspondence in the electrochemical system. In this work, a model has been proposed to a NiMH battery electrode to describe, in detail, the electrochemical process at the interface of this electrode. The theoretical impedance of a proposed circuit is a function of several variables. These adjusted variables to reach a good agreement between the theoretical spectra and the experimental spectra in the studied frequency. The Z-simplex software allows refining the experimental results. These results show a good superposition between the experimental spectra and the theoretical spectra corresponding to the proposed electric circuit. This leads to the conclusion that the proposed circuit describes the phenomena that take place at the interface of the hydride electrode

Eliciting Gul’s Theory of Disappointment Aversion by the Tradeoff Method

Gul’s (1991) theory of disappointment aversion (DA) has several attractive features, being intuitive, analytically tractable, and parsimonious. In spite of this, the DA model has received little attention in practical applications, which may be partly due to the absence of a procedure to elicit the model. We show how the trade-off method, developed by Wakker and Deneffe (1996), can be used to elicit DA. Our elicitation method is parameter-free: it requires no assumption about utility and/or disappointment aversion. Quantitative tests of DA in three outcome domains, monetary gains, monetary losses, and life-years, suggest that the DA model is too parsimonious. Of the other models of disappointment aversion that have been proposed in the literature, our data are most consistent with the model of Loomes and Sugden (1986)

Optical determination and identification of organic shells around nanoparticles: application to silver nanoparticles

We present a simple method to prove the presence of an organic shell around silver nanoparticles. This method is based on the comparison between optical extinction measurements of isolated nanoparticles and Mie calculations predicting the expected wavelength of the Localized Surface Plasmon Resonance of the nanoparticles with and without the presence of an organic layer. This method was applied to silver nanoparticles which seemed to be well protected from oxidation. Further experimental characterization via Surface Enhanced Raman Spectroscopy (SERS) measurements allowed to identify this protective shell as ethylene glycol. Combining LSPR and SERS measurements could thus give proof of both presence and identification for other plasmonic nanoparticles surrounded by organic shells

Méningiome en plaque sphéno-orbitaire: à propos d’un cas avec revue de la littérature

Le méningiome intra osseux est une variété des méningiomes ectopiques dans lequel les cellules méningothéliales envahissent la paroi osseuse et entraînent une hyperostose. Le méningiome en plaque, variante macroscopique des méningiomes intra osseux, est une tumeur rare et survient fréquemment au niveau de la région sphéno-orbitaire ce qui le confond avec les tumeurs osseuses primitives. Nous rapportons le cas d'une patiente de 50 ans qui présente une exophtalmie avec cécité unilatérale gauche d'installation progressive depuis un an. L'examen trouve une exophtalmie axile, indolore et non réductible ainsi qu'une limitation de la motilité oculaire dans tous les sens du regard. La palpation montre une masse temporale gauche dure et adhérente à l'os. L'examen du fond d'oeil trouve un oedème papillaire gauche. Le scanner montre une lésion ostéocondensante temporo-sphéno-orbitaire gauche avec envahissement locorégional. Le diagnostic préopératoire fut une tumeur osseuse essentiellement maligne primitive ou secondaire. L'étude histologique a révélée un méningiome meningothélial de type en plaque. La patiente a bénéficié d'une exérèse avec reconstruction chirurgicale. Aucune récidive n'a été notée après 1 an de recul

Reconciling Introspective Utility with Revealed Preference: Experimental Arguments Based on Prospect Theory

In an experiment, choice-based utilities are derived from choices under risk, and choiceless utilities from introspective strength-of-preference judgments. The well-known inconsistencies of risky utility, when analyzed through expected utility, are resolved by means of prospect theory. A consistent cardinal utility index for risky choice results. Remarkably, however, this cardinal index agrees well with the choiceless utilities. This finding suggests a relation between a choice-based and a choiceless concept. Such a relation would imply that direct judgments can provide useful data for economics, and can reinforce the revealed-preference approach. Implications for the classical debate on ordinal versus cardinal utility are discussed.This is a preprint of an article to be published in Journal of Econometric

Bilan hydrologique et envasement du barrage Saboun (Maroc)

La présente étude s'inscrit dans le cadre d'un programme de recherche sur la gestion des lacs et barrages collinaires en zone méditerranéenne HYDROMED. Elle a pour objectif le suivi hydrologique et la sédimentation du barrage collinaire Saboun, situé dans la zone de Tanger au Nord-Ouest du Maroc. Un dispositif hydro-pluviométrique automatique a été installé à ce sujet depuis novembre1997. Il a permis le suivi du bilan en eau de la retenue et l'analyse de son fonctionnement hydrologique. Parallèlement, une étude de la bathymétrie par sondage ponctuel a montré que le taux de sédimentation est de l'ordre de 2% par an. Cette perte en eau de la capacité totale de la retenue est une conséquence directe d'une forte dégradation des sols du bassin versant estimée à 115 T/ha/an.It is proposed that many Mediterranean countries could make better use of their water resources by constructing small hill reservoirs. Since 1980, Morocco has built more than 158 small dams in order to meet the requirements of rural population water use. Due to both environmental degradation and bad management, these small infrastructures are now in a critical situation. Furthermore, pollution and siltation, resulting in a deterioration of water quality and a reduction of water capacity, are problems at these sites.The present study is part of the HYDROMED research program on the hydrological balance of small dams in the Mediterranean area. Its objective is the monitoring of hydrological balance and siltation of a small dam, Saboun, located in Tangier in Northwest Morocco. A remote hydrological station was installed in November 1997. This station allowed the examination of the dam water balance and analyses of its hydrological function.The analyses of water balance demonstrated that the volume of water stored in the Saboun reservoir increased rapidly in November 1997, and was then followed by a progressive decrease. The load factor varied from 1.9 in 1997/98 to approximately 2 times the current capacity of reservoir, to only 0.3 in the following year 1998/99. These results show that even for a short hydrological period (2 years), the hydrological balance of the Saboun reservoir varied greatly as a result of the irregularity of its hydrological parameters. The essential reasons for this variability were the rainfall characteristics that control the runoff from the watershed and bad management practices.In addition, a bathymetric survey was carried out by a punctual method to estimate the rate of dam siltation and sedimentation from the watershed. The results of this control demonstrated that the dam siltation rate was about 2 % per year. This loss of total water retention capacity of the dam is the consequence of high specific soil degradation of the watershed. The rate of sediment delivered from watershed and deposited in the reservoir was estimated at 37 T/ha/year. The total soil erosion for watershed was estimated at 115 T/ha/year by integrating both the sediment evacuated at the time of dam overflow and the sediment deposited in stream flow. This erosion, which comes essentially from cultivated soil (95 % of the watershed surface), may have serious effects on the hydrological balance of the dam, particularly by reducing the reservoir capacity of the dam, and on the reservoir water quality

The use of reproductive vigor descriptors in studying genetic variability in nine Tunisian faba bean (Vicia faba L.) populations

A collection of nine Tunisian faba bean (Vicia faba) populations belonging to three botanical classes (Var. minor, var. equina and var. major) was evaluated using twenty seven agro-morphological traits. Analysis of variance, correlation coefficients and principal components analysis (PCA) were performed based on MVSP 3.13 program. Significant differences between populations were noted for most agromorphological traits in four main groups. The first group, positively correlated to the two axes, isrepresented by ‘Bachaar’ belonging to V. faba. var. minor, the second group, including V. faba. var. minor population (‘Massri’ and ‘Badï’), is positively correlated to the PC1 and negatively correlated to the PC2 while the third group, is composed of two V. faba var. major (‘Malti’ and ‘Batata’) and were positively and negatively correlated to the PC2 and PC1, respectively. Finally, the fourth group negatively correlated to the two axes, gathers the remaining population (‘Chahbi’, ‘Chemlali’, ‘Aguadulce’ and ‘Super Aguadulce’). The dendrogram based on Nei's genetic distance of the 9 populations using UPGMA method, show some genetic drift between populations.Key words: Faba bean, agromorphological traits, principal components analysis, UPGMA method

Do financial professionals behave according to prospect theory? An experimental study

Prospect theory is increasingly used to explain deviations from the traditional paradigm of rational agents. Empirical support for prospect theory comes mainly from laboratory experiments using student samples. It is obviously important to know whether and to what extent this support generalizes to more naturally occurring circumstances. This article explores this question and measures prospect theory for a sample of private bankers and fund managers. We obtained clear support for prospect theory. Our financial professionals behaved according to prospect theory and violated expected utility maximization. They were risk averse for gains and risk seeking for losses and their utility was concave for gains and (slightly) convex for losses. They were also averse to losses, but less so than commonly observed in laboratory studies and assumed in behavioral finance. A substantial minority focused on gains and largely ignored losses, behavior reminiscent of what caused the current financial crisis

A Tractable Method to Measure Utility and Loss Aversion under Prospect Theory

This paper provides an efficient method to measure utility under prospect theory, the most important descriptive theory of decision under uncertainty today. Our method is based on the elicitation of certainty equivalents for two-outcome prospects, a common way to measure utility. We applied our method in an experiment and found that most subjects were risk averse for gains and risk seeking for losses but had concave utility both for gains and for losses. This finding illustrates empirically that risk seeking and concave utility can coincide under prospect theory, a result that was derived theoretically by Chateauneuf and Cohen (1994). Utility was steeper for losses than for gains, which is consistent with loss aversion. Utility did not depend on the probability used in the elicitation, which offers support for prospect theory