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

La lagune de Ghar El Melh : Diagnostic écologique et perspectives d'aménagement hydraulique

La lagune de Ghar El Melh, située au Nord de la Tunisie (dans le Golfe de Tunis), est caractérisée par une superficie de 28,5 km2, une faible profondeur et une faible communication avec la mer. Actuellement, sous l'effet des actions anthropiques (les rejets terrestres), elle connaît une dégradation progressive de la qualité de ses eaux et sédiments dont les conséquences sont la chute de la richesse biologique et la réduction des ressources halieutiques de la lagune.Dans ce travail, nous présentons les résultats de l'analyse des caractéristiques physico-chimiques et biologiques des eaux de la lagune. Ces analyses montent bien l'hyper-eutrophisation du milieu caractérisé par de fortes concentrations des eaux en azote total et en phosphore total. Les résultats de simulation du fonctionnement hydrodynamique, que nous avons réalisée à l'aide d'un modèle à 2 dimensions intégré sur la hauteur, montrent une stagnation des eaux dans environ 80% de surface de la lagune qui a fortement amplifié la dégradation de la qualité de l'écosystème. Parmi plusieurs scénarios d'aménagements simulés, nous proposons la création d'une nouvelle communication avec la mer dont la simulation hydrodynamique montre une nette augmentation des échanges d'eau mer-lagune. Nous présentons ensuite un modèle écologique homogène de la lagune de Ghar El Melh qui a été mis au point et calibré en s'appuyant sur les mesures de terrain. Les simulations, avec ce modèle, montrent que l'arrêt total des rejets terrestres et la création d'un nouveau grau réduisent considérablement l'eutrophisation du milieu ce qui conduiraient certainement à une nette amélioration de la production halieutique dans la lagune.The Ghar El Melh lagoon is a Mediterranean water body, situated in Northeastern Tunisia, on the Northwestern side of the Gulf of Tunis. The Ghar El Melh lagoon is a vestigial part of the Utique Sea, and this lagoon was largely open at the time of the Roman invasion. Due to a combination of the shape of the coastline and alluvium deposits from the Medjerda River, this small gulf has become progressively closed from the Utique Sea, causing the lagoon to become progressively shaped to its present morphology. The coastal barrier separating the lagoon from the Mediterranean Sea was interrupted, allowing a permanent hydraulic communication across a local opening. The lagoon has an elliptical shape of approximately 28.5 km2 and an average depth of 0.8 m. Due to human activities within the lagoon itself and in the surrounding area, the lagoon ecosystem has suffered a progressive deterioration. This deterioration has led to a reduction in biodiversity resulting mainly in a decrease in fish resources and production.In order to improve the water quality of the lagoon for ecological and economical purposes, a diagnostic survey was carried out to characterize the present site conditions and to provide data for calibration of hydrodynamic and ecological models. The main results of the annual survey of biotic and non-biotic parameters demonstrated the existence of zones within the lagoon, with some seasonal variation. Thus, a decreasing biotic and non-biotic gradient was measured from the area of the lagoon under marine influence towards the bottom of the lagoon, under the continental and anthropogenic influence of the west side. The lagoon could be considered hypereutrophic with an annual average concentration of total phosphorus of 350 mg/m3. In order to conceptualize and optimise hydraulic structures for water quality improvement in the lagoon, a numerical model of the velocity fields (depth averaged) and water depth was used. The hydrodynamic model used was bi-dimensional, adapted for use in shallow lagoons. After model calibration using in-situ measurements, simulations were carried out to analyse the present hydrodynamic condition of the lagoon. Several stagnation zones were detected, which contributed to the altered water quality that was observed. Several management practices were proposed and simulated, aiming to control and improve the internal circulation and water exchange between the lagoon and the Mediterranean Sea. The main goal of these simulations was to improve water mobility inside the lagoon, and thus improve the water quality. The proposed hydraulic development measures consisted mainly of the creation of a new hydraulic communication in the south-eastern area of the lagoon, by dredging the south part of the lake or by channel creation in front of the new communication, reaching the stagnation zones of the lagoon. The impact assessment of the proposed development was verified with simulations using the bi-dimensional hydrodynamic model.An ecological model based on nitrogen and phosphorus cycling, was also developed for Ghar El Melh lagoon. It took into account one ecological compartment, the macro algae, that included Cladophora sp., Ulva sp. and Enteromorpha sp. Algae (A), inorganic nitrogen (NA), inorganic phosphorus (PA), organic nitrogen (NEorg) and organic phosphorus (PEorg), were the main variables of this model. After calibration of the model, a 10-yr simulation showed that all variables demonstrated a steady behaviour and that the lagoon eutrophication level remained. Model sensitivity analysis allowed the choice of some restoration scenarios and the prediction of their impacts on the ecological behaviour of the ecosystem. The simulations showed that wastewater load deviation combined with an increase in the sea-lagoon water exchange, instead of a decrease of nutrient diffusion from the sediments, led to a substantial decrease in the eutrophication level of the lagoon. Indeed, the annual average nutrient concentrations decreased from 270 to 60 mg/m3 for total nitrogen and from 350 to 20 mg/m3 for total phosphorus in the Ghar El Melh lagoon

Estabilización de aceite de oliva virgen extra ecológico con antioxidantes naturales de hojas de Artemisia absinthium obtenidos por maceración y extracción asistida por ultrasonido

Olive oil is the most popular product derived from Olea europaea L. due to its organoleptic characteristics and its beneficial effects on human health. Nowadays, there is a growing interest in olive oil enrichment with medicinal plants. In this regard, Artemisia absinthium L. is an edible source of antioxidants. The aim of the present study was to improve the oxidative stability and the nutritional value of Organic Tunisian Chetoui Olive oil by its enrichment with the phenolic compounds in Artemisia absinthium. The enrichment carried out by maceration and ultrasound-assisted extraction did not affect the organic criteria of olive oil. The comparative study, performed during one year of storage, showed that ultrasound-assisted extraction led to the lowest final peroxide and extinction coefficient values. At the end of storage, this method increased oleic acid content and biophenol contents. Furthermore, the anti-radical activities of enriched samples were higher than the control.El aceite de oliva es el producto derivado de Olea europaea L. muy popular debido a sus características organolépticas y sus efectos beneficiosos para la salud humana. En la actualidad existe un interés creciente por enriquecer el aceite de oliva con plantas medicinales. En este sentido, Artemisia absinthium L. es una fuente comestible de antioxidantes. El objetivo del presente estudio fue la mejora de la estabilidad oxidativa y el valor nutricional del aceite de oliva Chetoui tunecino orgánico mediante su enriquecimiento con compuestos fenólicos de Artemisia absinthium. El enriquecimiento realizado por maceración y extracción asistida por ultrasonidos no afectó a los criterios ecológicos del aceite de oliva. El estudio comparativo, realizado durante un año de almacenamiento, mostró que la extracción asistida por ultrasonidos condujo a los valores finales de peróxido y coeficientes de extinción más bajos. Al final del almacenamiento, este método aumentó el contenido de ácido oleico y de biofenoles. Además, las actividades antirradicales de las muestras enriquecidas fueron mayores que las del control

Biochemical characterization of a cefotaximehydrolysing &#946-lactamase encoded by a conjugative plasmid

During the nosocomials infections occurring in the intensive care unit of the military hospital of Tunis in 2005, the Enterobacter cloacae BW 1150 strain was isolated from a stool culture. This strain was found to have a high level resistance to broad-spectrum -lactams. Resistance profile against thevarious families of antibiotics was determined using the disc diffusion test. The minimal inhibitory concentrations values showed that this strain was resistant to the -lactams such as ampicillin and the extended spectrum cephalosporins (cefotaxime, ceftriaxon and cefpirome). Analysis of this strain by the disk diffusion test revealed synergies between amoxicillin-clavulanate (AMX-CA) and ceftriaxon, ceftazidime and cefotaxime. Cell sonicate of this isolate is very active against cefotaxime and showed aspecific activity (AS) of 7.54 U/mg for the same antibiotic. This activity was inhibited by the sulbactam and the clavulanic acid. Isoelectrofocusing methods revealed that the crude extract of the E. cloacae BW 1150 strain showed 1 - lactamase activity with an isoelectric piont (pI) of about 8. This activity was transferred by conjugation and was highly expressed in the transconjugant

Micromechanical based model for predicting aged rubber fracture properties

Environmental aging induces a slow and irreversible alteration of the rubber material’s macromolecular network. This alteration is triggered by two mechanisms which act at the microscale: crosslinking and chain scission. While crosslinking induces an early hardening of the material, chain scission leads to the occurrence of dangling chains responsible of the damage at the macromolecular scale. Consequently, the mechanical behavior as well as the fracture properties are affected. In this work, the effect of aging on the mechanical behavior up to fracture of elastomeric materials and the evolution of their fracture properties are first experimentally investigated. Further, a modeling attempt using an approach based upon a micro-mechanical but physical description of the aging mechanisms is proposed to predict the mechanical and fracture properties evolution of aged elastomeric materials. The proposed micro-mechanical model incorporates the concepts of residual stretch associated with the crosslinking mechanism and a so-called “healthy” elastic active chain (EAC) density associated with chain scission mechanism. The validity of the proposed approach is assessed using a wide set of experimental data either generated by the authors or available in the literature

High-level cefotaxime-resistant Proteus mirabilis strain isolated from a Tunisian intensive care unit ward: CTX-M-8 extended-spectrum β-lactamase coproduced with a plasmid mediated AmpC lactamase

The aimed of this study was to determine the implication of the biochemical and the molecular mechanism and to describe the properties of an extended-spectrum β-lactamase (ESBL) CTX-M-8 which was reported for the first time in Africa. A clinical isolate of Proteus mirabilis FS6449 was isolated from a patient hospitalized at an intensive care unit of the Military Hospital in Tunisia in 2009. Antimicrobial susceptibility was determined with the disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines and revealed that this strain was resistant to expanded-spectrum β-lactams. Analysis of P. mirabilis FS6449 by double-disk synergy test yielded a positive result suggesting the production of ESBLs. Sonicate of the isolate hydrolysed cefotaxime and benzylpenicillin. Isoelectric focusing exhibited four β-lactamase bands of isoelectric points (pIs) 5.6, 6, 6.5 and over 7.6. Polymerase chain reaction (PCR) and sequencing experiments revealed the presence of four β-lactamase genes encoding TEM-2, CTX-M-8, TEM-24, and an AmpC enzyme. Among them, the genes encoding TEM-24 and an AmpC enzyme were transferred to the recipient by conjugation experiments.Keywords: Resistance, β-lactamase, Proteus mirabilisAfrican Journal of Biotechnology Vol. 12(21), pp. 3278-328

Using Serious Games to Train Adaptive Emotional Regulation Strategies

[EN] Emotional Regulation (ER) strategies allow people to influence the emotions they feel, when they feel them, how they experience them, and how they express them in any situation. Deficiencies or deficits in ER strategies during the adolescence may become mental health problems in the future. The aim of this paper is to describe a virtual multiplatform system based on serious games that allows adolescents to train and evaluate their ER strategies. The system includes an ecological momentary assessment (EMA) tool, which allows the therapist to monitor the emotional status of teenagers every day in real time. Results obtained from a usability and effectiveness study about the EMA tool showed that adolescents preferred using the EMA tool than other classical instruments.This study was funded by Vicerrectorado de Investigación de la Universitat Politècnica de València, Spain, PAID-06-2011, R.N. 1984; by Ministerio de Educación y Ciencia, Spain, Project Game Teen (TIN2010-20187) and partially by projects Consolider-C (SEJ2006-14301/PSIC), “CIBER of Physiopathology of Obesity and Nutrition, an initiative of ISCIII” and Excellence Research Program PROMETEO (Generalitat Valenciana. Consellería de Educación, 2008-157). The work of Alejandro Rodríguez was supported by the Spanish MEC under an FPI Grant BES-2011-043316.Alcañiz Raya, ML.; Rodríguez Ortega, A.; Rey, B.; Parra Vargas, E. (2014). Using Serious Games to Train Adaptive Emotional Regulation Strategies. Lecture Notes in Computer Science. 8531:541-549. https://doi.org/10.1007/978-3-319-07632-4_51S5415498531Mennin, D., Farach, F.: Emotion and evolving treatments for adult psychopathology. Clinical Psychology: Science and Practice 14, 329–352 (2007)Serrano, A., Iborra, I.: Informe violencia entre compañeros en la escuela. Spanish Version (2005), http://www.centroreinasofia.esInforme Cisneros X.: Acoso y Violencia Escolar en España, por Iñaki Piñuel y Araceli Oñate. Editorial IIEDDI, Spanish Version (2007)Werner, K., Gross, J.J.: Emotion Regulation and Psychopathology. In: Emotion Regulation and Psychopathology: A Transdiagnostic Approach to Etiology and Treatment. Guildford Press (2010)Berking, M., Wupperman, P., Reichardt, A., Pejic, T., Dippel, A., Znoj, H.: Emotion-regulation skills as a treatment target in psychotherapy. Behaviour Research and Therapy 46, 1230–1237 (2008)Shields, A., Cicchetti, D.: Emotion regulation among school-age children: The development and validation of a new criterion Q-sort scale. Developmental Psychology 33(6), 906–916 (1997)Gross, J.J., John, O.P.: Individual differences in two emotion regulation processes: Implications for affect, relationships, and well-being. Journal of Personality and Social Psychology 85(2), 348–362 (2003)Gross, J.J., Levenson, R.W.: Hiding feelings: The acute effects of inhibiting negative and positive emotion. Journal of Abnormal Psychology 106, 95–103 (1997)Winn, et al.: The Effect of Student Construction of Virtual Environments on the Performance of High- and Low-Ability Students. Annual Meeting of the American Educational Research Association (2003)Pantelidis, V.: Reasons to use virtual reality in education. VR in the Schools 1(1) (1995)Playmancer, http://www.playmancer.euBen Moussa, M., Magnenat-Thalmann, N.: Applying affect recognition in serious games: The playMancer project. In: Egges, A., Geraerts, R., Overmars, M. (eds.) MIG 2009. LNCS, vol. 5884, pp. 53–62. Springer, Heidelberg (2009)Replay, http://www.replayproject.euFeldman, L.B., Gross, J.J., Conner, T., Benvenuto, M.: Knowing what you’re feeling and knowing what to do about it: mapping the relation between emotion differentiation and emotion regulation. Cognition and Emotion 15, 713–724 (2001

Nonadiabatic geometric phase induced by a counterpart of the Stark shift

We analyse the geometric phase due to the Stark shift in a system composed of a bosonic field, driven by time-dependent linear amplification, interacting dispersively with a two-level (fermionic) system. We show that a geometric phase factor in the joint state of the system, which depends on the fermionic state (resulting form the Stark shift), is introduced by the amplification process. A clear geometrical interpretation of this phenomenon is provided. We also show how to measure this effect in an interferometric experiment and to generate geometric "Schrodinger cat"-like states. Finally, considering the currently available technology, we discuss a feasible scheme to control and measure such geometric phases in the context of cavity quantum electrodynamics

Effects of Chia Seed Levels on Quality and Bio-Functional Profile of Stirred Yoghurt

Yoghurt is considered as a healthy food. Thus, it could convey functional and bioactive ingredients. Chia seeds are of great interest due to their ability to improve consumer health. In this study, chia seeds were added to stirred yoghurt at diff erent doses (1.5, 3, 4.5, or 6%). The effects of chia seeds on physicochemical, microbiological, and sensory qualities were assessed during 28 days of refrigerated storage. The results showed that chia seeds slightly decreased post-acidification, the lowest value was obtained in yogurt with 3% chia seeds (24°D), but syneresis rose significantly (P<0.05) when 6% of chia seeds was added. Furthermore, chia seeds promote viability of yoghurt bacteria, and antioxidant activity reached 62.20±0.02% in yoghurt added with 1.5% chia seeds. However, proteolysis is not affected. The effects of chia seeds were not dose dependent as 4.5% and 6% did not follow trend. These findings were affirmed by sensory characteristics. Thus, stirred yoghurt containing 1.5 or 3% of chia seeds proved to be the most adequate choices