330 research outputs found

    Des modèles biologiques à l'amélioration des plantes

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    Camel breeding development project in Tunisia

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    Camel breeding is of great socio-economic importance in southern Tunisia. Although, the size of the national camel herd has decreased over the years from 120000 to 56000 heads in 2014. Illegal export, low breeding efficiency, social modernization and lack of investment are the major causes of this decline. To remedy this situation, the Tunisian government has established a national program for development and research on camel production. This program is based on grants to farmers to encourage rearing of replacement females and fattening camels; improvement of pastures and water infrastructure, promotion of applied research in specialized centers. Research eff orts are centered on health, nutrition and improvement of rangelands, development of reproductive biotechnologies and genetic improvement. An attempt was carried out to genotype the local breeds of camels. Development of semen preservation and artificial insemination has met several challenges inherent to the peculiarities of reproduction in this species

    Projet de développement de l’élevage camelin en Tunisie

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    Camel breeding is of great socio-economic importance in southern Tunisia. Although, the size of the national camel herd has decreased over the years from 120 000 to 56 000 heads in 2014. Illegal export, low breeding efficiency, social modernization and lack of investment are the major causes of this decline. To remedy this situation, the Tunisian government has established a national program for development and research on camel production. This program is based on grants to farmers to encourage rearing of replacement females and fattening camels; improvement of pastures and water infrastructure, promotion of applied research in specialized centers. Research efforts are centered on health, nutrition and improvement of rangelands, development of reproductive biotechnologies and genetic improvement. An attempt was carried out to genotype the local breeds of camels. Development of semen preservation and artificial insemination has met several challenges inherent to the peculiarities of reproduction in this species. Keywords: Husbandry, reproduction, biotechnologies, Camel, TunisiaL’élevage du dromadaire joue un rôle socio-économique important dans le sud tunisien mais le nombre de dromadaires a connu ces dernières années une diminution importante de 120 000 à 56 000 en 2014. L’exportation illégale, le rendement faible de l’élevage, la modernisation de la vie des personnes et le manque d’investissement dans ce domaine sont les principales causes de cette diminution. Pour remédier à ce problème, l’état tunisien a proposé un programme national de développement et de recherche dans le domaine du dromadaire basé sur (1) l’encouragement des éleveurs par la subvention de l’élevage des femelles de remplacement et l’engraissement des chamelons, (2) l’amélioration des infrastructures dans les pâturages; notamment l’aménagement des points d’eau pour les animaux et (3) la promotion de la recherche appliquée dans les centres spécialisés. Les principaux thèmes de recherche sont axés sur la santé animale, l’alimentation des dromadaires et l’amélioration des zones de parcours, l’insémination artificielle et le transfert d’embryon et la sélection génétique des animaux. Dans le domaine de la biotechnologie de la reproduction, des essais ont été réalisés dans le typage génétique des dromadaires, la conservation du liquide séminal et l’insémination artificielle pour surmonter les difficultés particulières de la reproduction chez le dromadaire. Mots-clés: Élevage, reproduction, biotechnologies, dromadaire, Tunisi

    SmartEx: a case study on user profiling and adaptation in exhibition booths

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    An investigation into user profiling and adaptation with exhibition booth as a case study is reported. First a review of the field of exhibitions and trade fairs and a summary introduction to adaptation and profiling are given. We then introduce three criteria for the evaluation of exhibition booth: effectiveness, efficiency and affect. Effectiveness is related the amount of information collected, efficiency is a measurement of the time taken to collect the information, and affect is the perception of the experience and the mood booth visitors have during and after their visit. We have selected these criteria to assess adaptive and profiled exhibition booths, we call smart exhibition (SmartEx). The assessment is performed with an experiment with three test conditions (non-profiled/non adaptive, profiled/non-adaptive and profiled adaptive presentations). Results of the experiment are presented along discussion. While there is significant improvements of effectiveness and efficiency between the two-first test conditions, the improvement is not significant for the last test condition, for reasons explained. As for the affect, the results show that it has an under-estimated importance in people minds and that it should be addressed more carefully

    Security and Privacy Issues in Wireless Mesh Networks: A Survey

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    This book chapter identifies various security threats in wireless mesh network (WMN). Keeping in mind the critical requirement of security and user privacy in WMNs, this chapter provides a comprehensive overview of various possible attacks on different layers of the communication protocol stack for WMNs and their corresponding defense mechanisms. First, it identifies the security vulnerabilities in the physical, link, network, transport, application layers. Furthermore, various possible attacks on the key management protocols, user authentication and access control protocols, and user privacy preservation protocols are presented. After enumerating various possible attacks, the chapter provides a detailed discussion on various existing security mechanisms and protocols to defend against and wherever possible prevent the possible attacks. Comparative analyses are also presented on the security schemes with regards to the cryptographic schemes used, key management strategies deployed, use of any trusted third party, computation and communication overhead involved etc. The chapter then presents a brief discussion on various trust management approaches for WMNs since trust and reputation-based schemes are increasingly becoming popular for enforcing security in wireless networks. A number of open problems in security and privacy issues for WMNs are subsequently discussed before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the author's previous submission in arXiv submission: arXiv:1102.1226. There are some text overlaps with the previous submissio

    Ligand-Specific Factors Influencing GLP-1 Receptor Post-Endocytic Trafficking and Degradation in Pancreatic Beta Cells.

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    The glucagon-like peptide-1 receptor (GLP-1R) is an important regulator of blood glucose homeostasis. Ligand-specific differences in membrane trafficking of the GLP-1R influence its signalling properties and therapeutic potential in type 2 diabetes. Here, we have evaluated how different factors combine to control the post-endocytic trafficking of GLP-1R to recycling versus degradative pathways. Experiments were performed in primary islet cells, INS-1 832/3 clonal beta cells and HEK293 cells, using biorthogonal labelling of GLP-1R to determine its localisation and degradation after treatment with GLP-1, exendin-4 and several further GLP-1R agonist peptides. We also characterised the effect of a rare GLP1R coding variant, T149M, and the role of endosomal peptidase endothelin-converting enzyme-1 (ECE-1), in GLP1R trafficking. Our data reveal how treatment with GLP-1 versus exendin-4 is associated with preferential GLP-1R targeting towards a recycling pathway. GLP-1, but not exendin-4, is a substrate for ECE-1, and the resultant propensity to intra-endosomal degradation, in conjunction with differences in binding affinity, contributes to alterations in GLP-1R trafficking behaviours and degradation. The T149M GLP-1R variant shows reduced signalling and internalisation responses, which is likely to be due to disruption of the cytoplasmic region that couples to intracellular effectors. These observations provide insights into how ligand- and genotype-specific factors can influence GLP-1R trafficking

    The Dababiya corehole, Upper Nile Valley, Egypt : preliminary results

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    Author Posting. © Austrian Geological Society, 2012. This article is posted here by permission of Austrian Geological Society for personal use, not for redistribution. The definitive version was published in Austrian Journal of Earth Sciences 105, no. 1 (2012): 161-168.The Dababiya corehole was drilled in the Dababiya Quarry (Upper Nile Valley, Egypt), adjacent to the GSSP for the Paleocene/ Eocene boundary, to a total depth of 140 m and bottomed in the lower Maastrichtian Globotruncana aegyptiaca Zone of the Dakhla Shale Formation. Preliminary integrated studies on calcareous plankton (foraminifera, nannoplankton), benthic foraminifera, dinoflagellates, ammonites, geochemistry, clay mineralogy and geophysical logging indicate that: 1) The K/P boundary lies between 80.4 and 80.2 m, the Danian/Selandian boundary between ~ 41 and 43 m, the Selandian/Thanetian boundary at ~ 30 m (within the mid-part of the Tarawan Chalk) and the Paleocene/Eocene boundary at 11.75 m (base [planktonic foraminifera] Zone E1 and [calcareous nannoplankton] Zone NP9b); 2) the Dababiya Quarry Member (=Paleocene/Eocene Thermal Maximum interval) extends from 11.75 to 9.5 m, which is ~1 m less than in the adjacent GSSP outcrop.; 3) the Late Cretaceous (Maastrichtian) depositional environment was nearshore, tropical-sub tropical and nutrient rich; the latest Maastrichtian somewhat more restricted (coastal); and the early Danian cooler, low(er) salinity with increasing warmth and depth of water (i.e., more open water); 4) the Paleocene is further characterized by outer shelf (~ 200 m), warm water environments as supported by foraminifera P/B ratios > 85% (~79-28 m), whereas benthic foraminifera dominate (>70%) from ~27-12 m (Tarawan Chalk and Hanadi Member) due, perhaps, in part to increased dissolution (as observed in nearby outcrop samples over this interval); 5) during the PETM, enhanced hydrodynamic conditions are inferred to have occurred on the sea-floor with increased river discharge (in agreement with sedimentologic evidence), itself a likely cause for very high enhanced biological productivity on the epicontinental shelf of Egypt; 6) correlation of in situ measured geophysical logs of Natural Gamma Ray (GR), Single-Point Resistance (PR), Self-Potential (SP), magnetic susceptibility (MS), and Resistivity, and Short Normal (SN) and Long Normal (LN) showed correspondence to the lithologic units. The Dababiya Quarry Member, in particular, is characterized by very high Gamma Ray and Resistivity Short Normal values.The Dababiya corehole was made possible by the financial support of the National Geographic Society

    Gene encoder: a feature selection technique through unsupervised deep learning-based clustering for large gene expression data

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    © 2020, Springer-Verlag London Ltd., part of Springer Nature. Cancer is a severe condition of uncontrolled cell division that results in a tumor formation that spreads to other tissues of the body. Therefore, the development of new medication and treatment methods for this is in demand. Classification of microarray data plays a vital role in handling such situations. The relevant gene selection is an important step for the classification of microarray data. This work presents gene encoder, an unsupervised two-stage feature selection technique for the cancer samples’ classification. The first stage aggregates three filter methods, namely principal component analysis, correlation, and spectral-based feature selection techniques. Next, the genetic algorithm is used, which evaluates the chromosome utilizing the autoencoder-based clustering. The resultant feature subset is used for the classification task. Three classifiers, namely support vector machine, k-nearest neighbors, and random forest, are used in this work to avoid the dependency on any one classifier. Six benchmark gene expression datasets are used for the performance evaluation, and a comparison is made with four state-of-the-art related algorithms. Three sets of experiments are carried out to evaluate the proposed method. These experiments are for the evaluation of the selected features based on sample-based clustering, adjusting optimal parameters, and for selecting better performing classifier. The comparison is based on accuracy, recall, false positive rate, precision, F-measure, and entropy. The obtained results suggest better performance of the current proposal
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