Computer Aided Aroma Design. II. Quantitative structure-odour relationship

Computer Aided Aroma Design (CAAD) is likely to become a hot issue as the REACH EC document targets many aroma compounds to require substitution. The two crucial steps in CAMD are the generation of candidate molecules and the estimation of properties, which can be difficult when complex molecular structures like odours are sought and their odour quality are definitely subjective or their odour intensity are partly subjective as stated in Rossitier’s review (1996). The CAAD methodology and a novel molecular framework were presented in part I. Part II focuses on a classification methodology to characterize the odour quality of molecules based on Structure – Odour Relation (SOR). Using 2D and 3D molecular descriptors, Linear Discriminant Analysis (LDA) and Artificial Neural Network are compared in favour of LDA. The classification into balsamic / non balsamic quality was satisfactorily solved. The classification among five sub notes of the balsamic quality was less successful, partly due to the selection of the Aldrich’s Catalog as the reference classification. For the second case, it is shown that the sweet sub note considered in Aldrich’s Catalog is not a relevant sub note, confirming the alternative and popular classification of Jaubert et al., (1995), the field of odours

Computer Aided Aroma Design. I. Molecular knowledge framework

Computer Aided Aroma Design (CAAD) is likely to become a hot issue as the REACH EC document targets many aroma compounds to require substitution. The two crucial steps in CAMD are the generation of candidate molecules and the estimation of properties, which can be difficult when complex molecular structures like odours are sought and when their odour quality are definitely subjective whereas their odour intensity are partly subjective as stated in Rossitier’s review (1996). In part I, provided that classification rules like those presented in part II exist to assess the odour quality, the CAAD methodology presented proceeds with a multilevel approach matched by a versatile and novel molecular framework. It can distinguish the infinitesimal chemical structure differences, like in isomers, that are responsible for different odour quality and intensity. Besides, its chemical graph concepts are well suited for genetic algorithm sampling techniques used for an efficient screening of large molecules such as aroma. Finally, an input/output XML format based on the aggregation of CML and ThermoML enables to store the molecular classes but also any subjective or objective property values computed during the CAAD process

La rétinopathie de décompression oculaire: une complication rare de la trabéculectomie

Une patiente âgée de 50 ans, monophtalme de l'oeil droit nous a été adressée pour une crise aigüe de glaucome par fermeture de l'angle de l'oeil droit qui a évolué vers la chronicité malgré le traitement médical précoce. A j1 post trabéculectomie l'examen retrouve une hypotonie à 6 mmHg avec au fond d'oeil présence d'un oedème  papillaire et de multiples hémorragies pré-rétiniennes rondes dont certaines à centre blanc localisées au pôle postérieur et en moyenne périphérie, épargnant la macula. L'évolution spontanée était favorable avec  stabilisation de la pression intra-oculaire (PIO) à 12 mm Hg et nettoyage du fond de l'oeil au bout de 6  semaines. Le bilan hématologique était sans particularités. La rétinopathie de décompression oculaire est une complication rare de la trabéculectomie. Son évolution est habituellement favorable. Dans certains cas une perturbation du bilan hématologique a été incriminée. Enfin cette complication peut être prévenue en évitant les variations brutales de la PIO.Key words: Rétinopathie, décompression oculaire, trabéculectomi

A Consumer-based Assessment Of Alliance Performance: An Examination Of Consumer Value, Satisfaction And Post-purchase Behavior

Strategic alliances have become a recognized strategy used by firms in the pursuit of their diverse organizational objectives. Consequently, the literature on alliances is replete with research investigating the value strategic alliances generate for participating organizations. Strategic alliances have been shown to contribute to firm value through numerous sources, including scale economies, effective risk management, cost efficient market entries, and learning from partners. Largely overlooked in the literature however, are issues investigating the relationship between strategic alliances and one of the organization\u27s most important constituents, the consumer. Questions such as how the consumer reacts to inter-firm alliances, how strategic alliances impact consumer value, satisfaction, and customer post-purchase behavior have yet to be answered. This lacuna has been recently highlighted by prominent researchers in the discipline (Rindfleisch and Moorman 2003). Focusing on marketing alliances, the present dissertation attempts to address this gap in the alliance literature by advancing and testing a theoretical framework examining consumers\u27 cognitive, affective, and behavioral reactions to organizational strategic alliances. The dissertation also contributes to the satisfaction literature. Scholars in this area have traditionally viewed satisfaction as a cognitive response to the comparison of actual consumption experiences with some comparison standard (confirmation/disconfirmation paradigm). Recently however, there have been increasing calls for satisfaction measures to capture not just how the customer thinks the product performed relative to the comparison standard, but also the resulting customer emotion. The study provides additional support of an affective route to customer satisfaction, particularly when customer hedonic value is enhanced. Moreover, the association between customer satisfaction and behavioral outcomes is also examined. While prior research shows that satisfaction is positively related to loyalty and word of mouth and negatively related to intentions to switch, it was found that these relationships are even stronger in the presence of alliances. The results of this dissertation provide important theoretical and managerial insights. The strategic alliance literature is enhanced insofar as this is the first effort aimed at investigating the impact of strategic alliances on the consumer. The study examines the relationship between marketing alliances and customer value, particularly utilitarian and hedonic value, as well as the moderating role of alliance type (functional or symbolic) in this relationship. From a managerial perspective, engaging in strategic alliances is strategically critical and costly. By providing insight into how alliances enhance consumer value, and how in turn value enhancement is related to customer satisfaction and behavioral outcomes, the present research will help managers make more appropriate and better-informed alliance decisions

Relais coopératifs dans un réseau de capteurs : performances limites et stratégies

Les réseaux de capteurs ont connu un grand essor ces dix dernières années. Ils interviennent dans tous les domaines de notre vie quotidienne et la rendent plus aisée. Malgré ce grand succès des réseaux de capteurs, plusieurs problèmes restent encore ouverts. La capacité énergétique et la fragilité du canal radio des réseaux de capteurs affectent gravement leurs performances. La communication coopérative représente une solution efficace pour lutter contre l'instabilité du canal radio et afin d'économiser plus d'énergie. Nous proposons dans ce manuscrit, d'utiliser la communication coopérative, en premier lieu, au niveau de la couche MAC afin de mettre en place un accès au canal coopératif et non égoïste. En second lieu, nous utilisons la communication coopérative au niveau de la couche réseau dans le but d'établir des chemins de routage plus stables et plus robustes. ABSTRACT : Wireless sensor networks (WSN) have known a great development during the last decade. They intervene in all the domain of our everyday life to make it easier. Despite the success of WSN several problems have to be solved. The restricted energy capacity and the randomness of the wireless channel seriously affect the performances of the WSN. Cooperative communication represents an efficient solution to reduce the instability of the wireless channel and to optimize energy. In this thesis we propose to use cooperative communications at the MAC and network layer in order to set up a cooperative access to the channel and to establish more robust routing paths

Enhanced relay selection decision for cooperative communication in energy constrained networks

International audienceMost of current works related to relay selection algorithms in cooperative communications use the Channel State Information (CSI) to decide whether to use one or another neighbor as a relay. Therefore in wireless sensor networks where the energy is the major constraint such algorithms may lead to quick battery drain of the nodes having the best links. In this paper we propose to enhance the relay selection decision process by taking into account the energy metric in addition to CSI. The results show that we can redistribute the consumed energy when we use the energy as a relay selection metric

Prise en charge des complications de la chirurgie partielle du larynx

Introduction : Le cancer du larynx est un cancer fréquent occupant la première place des cancers des voies aéro-digestives chez l’homme en Tunisie. Le tabac est le principal facteur favorisant surtout s’il est associé à l’éthylisme chronique. Il s’agit le plus souvent d’un carcinome épidermoïde plus ou moins différencié. Son pronostic est généralement bon, en raison de son développement dans un tube rigide bien limité et d’un traitement chirurgical actuellement bien codifié. La chirurgie partielle du cancer du larynx est une chirurgie à risque de complications postopératoires nécessitant une prise en charge adéquate.Patients et méthodes : Notre série comprend 54 patients ayant bénéficié d’une chirurgie partielle du larynx au sein du service de chirurgie carcinologique de l’institut Salah Azaiez sur une période de 15 ans (1997-2011).But : Présenter notre expérience en matière de prise en charge des complications de la chirurgie partielle du larynx.Résultats : La moyenne d’âge de nos patients était de 54,9 ans avec des extrêmes allant de 33 à 69 ans. La prédominance masculine était nette avec un sex-ratio de 26. La consommation tabagique était notée dans 92,6% des cas et la dysphonie était présente chez 40 patients porteurs d’une tumeur à localisation glottique. Six types d’interventions ont été pratiqués: cordectomie (9 cas), laryngectomie fronto-latérale (4 cas), laryngectomie frontale antérieure reconstructive type Tucker (10 cas), laryngectomie partielle supra-cricoïdienne avec crico-hyoïdopexie (CHP) (4 cas), laryngectomie partielle supra-cricoïdienne avec crico-hyoïdo-épiglottopexie (CHEP) (24 cas) et laryngectomie horizontale supra-glottique (3 cas). Une antibioprophylaxie était administrée chez 79,6% des patients pour une durée moyenne de 7 jours. Les complications postopératoires ont été analysées et discutées en fonction du type de la chirurgie partielle pratiquée et du type d’antibiothérapie utilisée. Ces complications étaient les suivantes: infection du trachéostome (20,4%), infection de paroi (5 cas), complications respiratoires (29,6%), emphysème sous cutané (7,4%), fistule salivaire (1 cas) et pancréatite aigüe (1 cas).Conclusion : Cette étude montre dans l’ensemble des bons résultats tant sur le plan infectieux que respiratoires, justifiant ainsi l’importance de la prise en charge des complications de la chirurgie partielle du cancer du larynx.Introduction : Laryngeal cancer is a common cancer occurring mainly in men. Smoking is the main risk factor especially if associated with chronic alcoholism. Squamous cell carcinoma is the most common histologic type. Prognosis is generally good, due to the development of the tumor in a very limited rigid tube and to a well-codified surgical treatment. Partial surgery of laryngeal cancer is characterized by postoperative complications requiring an adequate management.Methods : Our series includes 54 cases of laryngeal cancer treated with partial laryngectomy in the ENT department of Salah Azaiez Institute over a period of 15 years from 1997 to 2011.Objective : To present our experience in the management of partial laryngeal surgery complications.Results : Average age of our patients was 54.9 years ranging from 33 to 69 years. Male predominance was marked with a sex ratio of 26. Tobacco abuse was found in 92.6%. Dysphonia was the most common symptom found in 40 patients with glottic cancer. Six varieties of partial laryngectomy were performed: cordectomy (9 cases), fronto-lateral laryngectomy (4 cases), fronto-anterior reconstructive laryngectomy (10 cases), partial supra-cricoid laryngectomy with CHP (4 cases), partial supra-cricoid laryngectomy with CHEP (24 cases) and supra glottic horizontal laryngectomy (3 cases). 79.6 % of our patients received prophylactic antibiotics for an average of 7 days. Postoperative complications were analyzed and discussed in terms of the type of surgery performed and the antibiotic used. Complications observed were: infection of the tracheostoma (20.4%), parietal infection (5 cases), respiratory complications (29.6%), subcutaneous emphysema (7.4%), salivary fistula (1 case) and acute pancreatitis (1 case).Conclusion : This study shows overall good results for partial laryngeal cancer surgery with minimal post-operative complications and oncologic failure justifying the importance of an early management of these complications

A Combined Relay-Selection and Routing Protocol for Cooperative Wireless Sensor Networks

International audienceIn wireless sensor networks several constraints decrease communications performances. In fact, channel randomness and energy restrictions make classical routing protocols inefficient. Therefore, the design of new routing protocols that cope with these constraints become mandatory. The main objective of this paper is to present a multi-objective routing algorithm RBCR that computes routing path based on the energy consumption and channel qualities. Additionally, the channel qualities are evaluated based on the presence of relay nodes. Compared to AODV and AODV associated to a cooperative MAC protocol, RBCR provides better performances in term of delivery ratio, power consumption and traffic load

Quantitative Structure - Odor Relationship: Using of Multidimensional Data Analysis and Neutral Network Approaches

Structure - odor relationships (SOR) are key issues for the synthesis of new odorant molecules. But, this relation is hard to model, due to limited understanding of olfaction phenomena and the subjectivity of odor quantity and quality as stated in Rossitier's review (1996). Many molecular descriptors are used to correlate molecule's odor, but no universal rules emerge in this field. In this paper, we focus on the use of molecular descriptors as an alternative approach in the prediction of odors, by the mean of regression techniques. Principal Component Analysis (PCA) and Stepwise Collinearity Diagnosis (SCD) techniques are used to reduce the dimensionality of data, by the identification of significant molecular descriptors. Then, the chosen molecular descriptors are used with a neural networks algorithm to correlate the structure to molecular odor quality. The results are validated on balsamic flavor

COSMIC: A Cooperative MAC Protocol for WSN with Minimal Control Messages

International audienceOver the last decade cooperative communication in wireless sensor networks (WSN) received much attention. A lot of works have been done to propose a MAC layer that supports cooperative relaying. The majority of these works tried to adapt the IEEE 802.11 MAC protocol to sensor networks. The adapted protocols use a lot of overhead (such as the use of RTS/CTS as well as other messages used to allow cooperation) that consumes energy. In this paper we propose a CSMA/CA based MAC protocol that supports cooperative communication with a minimum overhead: COSMIC (A Cooperative MAC Protocol for WSN with Minimal Control Messages). Relay selection in this new protocol is performed using both the channel state information (CSI) and the remaining energy. Simulation results show that COSMIC is able to increase the network lifetime by 25%