Managing nitrate pollution in a Tunisian irrigated area: A multi-criteria analysis approach

In Tunisia, the extension of irrigated area is justified by its important role in the development and diversification of agricultural production. Nevertheless, the strong intensification of the agricultural activities may lead to the pollution of underground water resources due to an excess use of fertilisers and other chemical products. In fact, the high nitrate concentrations observed in some Tunisian irrigated areas, are related to the excessive use of nitrate fertilizers in intensive agriculture. The objective of the present study is to implement decision-making methods allowing a better combination of factors production by optimization of an economic objective and an environmental objective. This research is based on multi-criteria modelling through the optimization of two conflict objectives: an economic objective as settled by farmer in the short or medium-run (Gross margin), and an environmental objective (nitrate pollution reduction) as a long-run objective of the decision maker in order to ensure the continuity of agriculture activities and ecosystems sustainability. Data were collected through a survey conducted in the irrigated area of Kalaât El Andalous in Tunisia with a sample containing 57 farms. Efficient solutions were obtained and compared through the "constraints", "NISE" and "compromises" methods. Main results obtained indicate a significant degree of conflict between these two objectives. Indeed the maximization of the total gross margin involves an increase in the degrees of nitrate pollution and conversely. Finally, some policy implications are presented.Nitrate pollution, environmental impact, multicriteria analysis, Environmental Economics and Policy,

Selection of pomegranate (Punica granatum L.) in south-eastern Tunisia

Tunisia is one of the main producers and exporters of pomegranate (Punica granatum L.) in the world. Due to its international importance, the selection of both quantitative and qualitative most desirable varieties has become a necessity. To select new cultivars that are most appropriate for commercial use, 21 accessions were collected from different regions of south-east Tunisia. 24 morphological characters of the tree and fruit were studied for each accession. This study has revealed considerable diversity especially concerning the tree vigor, the fruit size and color and the acidity of juice. Taking into account all comments, some trees are considered particularly efficient in south-eastern Tunisia.Key words: South-east Tunisia, Punica granatum L., selection, morphological characters

A new feature extraction method based on clustering for face recognition

Part 13: Feature Extraction - MinimizationInternational audienceWhen solving a pattern classification problem, it is common to apply a feature extraction method as a pre-processing step, not only to reduce the computation complexity but also to obtain better classification performance by reducing the amount of irrelevant and redundant information in the data. In this study, we investigate a novel schema for linear feature extraction in classification problems. The method we have proposed is based on clustering technique to realize feature extraction. It focuses in identifying and transforming redundant information in the data. A new similarity measure-based trend analysis is devised to identify those features. The simulation results on face recognition show that the proposed method gives better or competitive results when compared to conventional unsupervised methods like PCA and ICA

Wake control using synthetic jets

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.The interactions of wake of an elongated bluff body and the periodic flow emanating from a pair of synthetic jets placed symmetrically at the trailing edge, spanning the width of the plate, were experimentally studied for the purpose of quantifying the flow physics that led to wake drag reduction. The experiments were carried out in a low turbulence wind tunnel at Reynolds number, Reh based on the flat plate thickness h, of about 7200. The synthetic jet actuators, providing a global momentum addition of Cμ=24%, were positioned symmetrically at the model base at a distance of ± 0.27 h from the base centerline to introduce perturbations at early stages of the shear layers’ development. The synthetic jet actuation frequency was selected to be about 75% the vortex shedding frequency of the natural wake. Two-component velocity measurements were acquired using Particle Image Velocimetry (PIV) and reported for natural wake and controlled wake using symmetric synchronous actuation and out-of-phase actuation. In this work, mean velocity profiles, Reynolds stresses and coherent structures and their dynamics in the wake of a bluff body were evaluated as the initial conditions (injection configurations) were changed. Furthermore, phaseaveraged velocity fields through the vorticity contours were determined to provide insights into the actuation mechanisms namely, the role of the synthetic jet vortex structures on the flow dynamics.dc201

Analysis of genetic diversity of the critically endangered Onobrychis conferta subsp. conferta using cross-genera transferability of SSR markers developed from related legume species

The use of transferable cross-species/genera SSR markers is an alternative strategy to ensure availability of markers in genomic resources-limited crops, such as critically endangered species. Eighteen microsatellite markers derived from the genomes of Medicago truncatula Gaertn., Phaseolus vulgaris L. and Onobrychis viciifolia Scop. were tested for transferability and used to study the genetic diversity of the three remaining populations of the critically endangered species Onobrychis conferta subsp. conferta, collected from their natural habitats. All pairs of primers tested were found to be polymorphic and reproducible. A total of 257 alleles were obtained from 134 loci, resulting in an average of 1.93 alleles per locus. The average number of alleles per accession was 51.4, yielding an average of 14.27 alleles per SSR marker and accession. The lowest number of alleles was recorded in O. conferta from Aïn Dyssa, with 37 alleles, while the highest was observed in O. viciifolia, with 63 alleles. Each SSR amplified 3-16 alleles. The MTIC343 primer yielded the highest number of loci (16 loci). The mean Polymorphism Information Content (PIC), Marker Index (MI), and Resolving Power (Rp) were 0.36, 2.22, and 4.58, respectively, indicating a high level of polymorphism in the studied SSR markers. UPGMA cluster analysis grouped genotypes into two main clusters in corroboration with the morphological distinction of sections. Our study demonstrated that O. conferta subsp. conferta genomes could be successfully examined using other legume SSR markers, providing a valuable tool to detect polymorphism for future genetic studies, breeding programs, and conservation strategies, addressing the lack of available SSR markers in this genus. These microsatellite loci may help to further survey the adaptive evolution and genetic variation of Onobrychis conferta conservation

Diagnosis and monitoring of Alzheimer Disease with saliva biomarker BACE1

Alzheimer’s disease (AD) is characterized by the slow decline of cognition and functional abilities over time. The diagnosis for probable and possible AD relies principally on clinical criteria. The confirmation of the disease is made post-mortem by identifying extracellular senile plaques and intraneuronal fibrillary tangles in the brains of subjects with clinically defined dementia. However, the field critically lacks validated AD specific peripheral biomarkers to support the diagnosis in living patients or for early detection of patients at risk before symptoms appear. BACE1 (Beta site amyloid precursor protein cleaving enzyme 1) cleaves Amyloid Precursor Protein (APP) at two beta sites and represents a key target enzyme in the monitoring and possible treatment of AD. In our preliminary study, we evaluated the usefulness of salivary BACE1 to determine risk to develop AD in clinically normal patients. A preliminary in house laboratory grading system for BACE1 content in saliva was established with high levels of salivary BACE1 present in older patients and putatively at risk to develop AD. BACE1 seems to be a useful biomarker to help diagnose AD and to monitor disease progression, and remarkably regression, when treated with stem cell secretome

Bioactive Lipids, Antibacterial, Hypoglycaemic, and Antioxidant Potentials of Immature and Mature Vicia faba L. Seeds Cultivated in Tunisia

Both the immature and mature Vicia faba L. seeds are used for human consumption. However, there is a lack of information on the phytochemical composition and the potent biological properties of the immature seeds. The aim of the present study was to establish the profile of bioactive lipids as well as the antibacterial, antioxidant, and α-amylase and α-glucosidase inhibitory capacities of the immature and mature Vicia faba L. seeds. The studied petroleum ether extracts contain different bioactive compounds such as β-sitosterol, lupeol, β-amyrin, α-tocopherol, and γ-tocopherol. The extracts of the immature seeds exhibited higher antioxidant and antibacterial activities than those of mature ones. All tested extracts exerted higher inhibition on α-glucosidase than α-amylase. The immature seeds appeared as promising sources of natural antioxidants, antibacterial compounds, and α-amylase and α-glucosidase inhibitors. Thus, the immature Vicia faba L. seeds have a great potential as functional foods providing health beneficial properties

Efficacy of the Non-Pathogenic Agrobacterium Strains K84 and K1026 against Crown Gall in Tunisia

The non-pathogenic Agrobacterium radiobacter strain K84 and its genetically modified (GEM) strain K1026 were tested for their effectiveness against local Tunisian strains and two reference strains (C58 and B6) of the crown gall bacterium Agrobacterium tumefaciens. Tests in planta were carried out on herbaceous plants (tomato and tagetes) and on some sensitive rootstocks (bitter almond, peach almond hybrid GF677 and quince BA29). In vitro tests showed that both K84 and K1026 were effective and that the difference between these strains was not statistically significant. On tomato and tagetes, strain K84 was effective against all crown gall isolates with the exception of the A. tumefaciens reference strain B6. GEM strain K1026 was very effective against all isolates from Tunisia and against the reference strains. Both antagonistic strains significantly reduced the percentage of galled plants as well as the number of galls per plant. Under field conditions, both antagonists controlled crown gall effectively. Best results were obtained on the bitter almond-tree rootstock. Antagonist effectiveness was less evident on quince BA29 and peach almond GF677 rootstocks. The genetically modified strain K1026 is of interest in controlling crown gall disease in Tunisia

Adjustment of the lactation curve of Holstein cows according to Wood's model

Les deux objectifs de cette étude ont été d’ajuster les courbes de lactation des vaches Holstein en Tunisie et d’étudier les facteurs de variations des paramètres de ces dernières. L’ajustement a été réalisé selon le modèle de Wood pour les 9 premières lactations. Les données proviennent de 190 905 contrôles journaliers de la quantité de lait, de la matière grasse (MG) et de la matière protéique (MP), collectés entre 1995 et 2011 et répartis sur 10 troupeaux issus de 4 différents secteurs de production. La fonction de Wood a servi pour modéliser les courbes de lactations par la régression non linéaire. Les paramètres de la courbe de lactation «a», MG et MP les plus élevées ont été enregistrés à la 3ème, 4èmeet 5ème lactation, contrairement au paramètre «b». Le paramètre «c» et la persistance la plus élevée de la courbe de lactation ont été enregistrés à la 1ère lactation. Pour les paramètres des courbes de lactation et ses traits (lait, MG et MP), ils ont tous été affectés par les facteurs inclus dans le modèle d’analyse à savoir le secteur, le troupeau, l’interaction année de vêlage-saison de vêlage et le numéro de lactation. Mots clés: Contrôles journaliers, ajustement, Wood, courbe de lactationThe two objectives of this study were to adjust the lactation curves of Holstein cows in Tunisia and to study the factors of variation of the parameters of the latter. The adjustment was made according to the Wood model for the first 9 lactations. The data comes from 190,905 daily checks of the quantity of milk, fat (MG) and protein (MP), collected between 1995 and 2011 and distributed over 10 herds from 4 different production sectors. Wood's function was used to model the lactation curves by nonlinear regression. The highest “a”, MG and MP lactation curve parameters were recorded at the 3rd, 4th and 5th lactation, unlike the “b” parameter. The “c” parameter and the highest persistence of the lactation curve were recorded in the 1st lactation. For the parameters of the lactation curves and its traits (milk, fat and protein), they were all affected by the factors included in the analysis model, namely the sector, the herd, the interaction year of calving - calving season and lactation number. Keywords: Daily checks, adjustment, Wood, lactation curv