Diversité spécifique de la macrofaune benthique dans la côte ouest de la baie de Tunis et la côte de l'île de Djerba (sud-ouest de la Méditerranée)

In this study, 21 stations were sampled, 11 in the Djerba island coast and 10 in the western coast of Tunis bay. Then, samples were sifted on a square mesh of 1 mm a side, and the animals collected were identified and counted. Lacking an efficient single index suitable for application in all situations, several traditional nonparametric indices of biodiversity were selected, calculated and discussed. Results show that the community composition is totally different in the two studied sites, and, within each site, several species are common, butthey exchange the leader ranks from one station to another. For biodiversity measurement and since results show varying values depending on indices at several stations, an arithmetic mean index was calculated at each station on the basis of the most similar indices. It shows that, overall, the biodiversity is significantly higher in Tunis bay coast than in Djerba coast. These results are more reliable considering the real environmental /anthropogenic constraints imposed on both sites. Indeed, Djerba coast is subject, these last decades, to strong industrial, urban and fishing activities, causing significant regression of benthic habitats, which can led to a reduction of the biodiversity.Dans cette étude, 21 stations ont été échantillonnées, 11 dans la côte de l'île de Djerba et 10 dans la côte ouest de la baie de Tunis. Ensuite, les échantillons ont été tamisés sur une maille carrée de 1 mm de côté, et les animaux capturés ont été identifiés et comptés. Faute d'un indice unique efficace et adapté à toutes les situations, plusieurs indices traditionnels de biodiversité ont été choisis, calculés et discutés. Les résultats montrent que la composition de la communauté est totalement différente dans les deux sites étudiés, et, à chaque site, plusieurs espèces sont communes, mais ils se substituent aux places des leaders d'une station à l’autre. Pour la mesure de la biodiversité et étant donné la grande différence dans les valeurs enregistrées par les indices retenus, une moyenne arithmétique a été calculée à chaque station sur la base des indices les plus cohérents. Elle montre que, globalement, la biodiversité est nettement plus élevée dans la baie de Tunis par rapport à la côte de Djerba. Ces résultats semblent être plus fiables tenant en compte les contraintes réelles environnementales et anthropiques imposées aux deux sites. En effet, la côte de Djerba est l'objet, ces dernières décennies, à de fortes activités urbaines et de pêche industrielle, entraînant une régression significative des habitats benthiques, ce qui peut conduire à la réduction de la biodiversité

Trammel net catch species composition, catch rates and metiers in southern European waters: A multivariate approach

We identified and quantified the effect of season, depth, and inner and outer panel mesh size on the trammel net catch species composition and catch rates in four southern European areas (Northeast Atlantic: Basque Country, Spain; Algarve, Portugal; Gulf of Cadiz, Spain; Mediterranean: Cyclades, Greece), all of which are characterised by important trammel net fisheries. In each area, we conducted, in 1999-2000, seasonal, experimental fishing trials at various depths with trammel nets of six different inner/outer panel mesh combinations (i.e., two large outer panel meshes and three small inner panel meshes). Overall, our study covered some of the most commonly used inner panel mesh sizes, ranging from 40 to 140 mm (stretched). We analysed the species composition and catch rates of the different inner/outer panel combinations with regression, multivariate analysis (cluster analysis and multidimensional scaling) and other 'community' techniques (number of species, dominance curves). All our analyses indicated that the outer panel mesh sizes used in the present study did not significantly affect the catch characteristics in terms of number of species, catch rates and species composition. Multivariate analyses and seasonal dominance plots indicated that in Basque, Algarve and Cyclades waters, where sampling covered wide depth ranges, both season and depth strongly affected catch species compositions. For the Gulf of Cadiz, where sampling was restricted to depths 10-30 m, season was the only factor affecting catch species composition and thus group formation. In contrast, the inner panel mesh size did not generally affect multidimensional group formation in all areas but affected the dominance of the species caught in the Algarve and the Gulf of Cadiz. Multivariate analyses also revealed 11 different metiers (i.e., season-depth-species-inner panel mesh size combinations) in the four areas. This clearly indicated the existence of trammel net 'hot spots', which represent essential habitats (e.g., spawning, nursery or wintering grounds) of the life history of the targeted and associated species. The number of specimens caught declined significantly with inner panel mesh size in all areas. We attributed this to the exponential decline in abundance with size, both within- and between-species. In contrast, the number of species caught in each area was not related to the inner mesh size. This was unexpected and might be a consequence of the wide size-selective range of trammel nets. (c) 2006 Elsevier B.V All rights reserved

Evaluation of extra-virgin olive oils shelf life using an electronic tongue-chemometric approach

Physicochemical quality parameters, olfactory and gustatoryretronasal positive sensations of extra-virgin olive oils vary during storage leading to a decrease in the overall quality. Olive oil quality decline may prevent the compliance of olive oil quality with labeling and significantly reduce shelf life, resulting in important economic losses and negatively condition the consumer confidence. The feasibility of applying an electronic tongue to assess olive oils usual commercial light storage conditions and storage time was evaluated and compared with the discrimination potential of physicochemical or positive olfactory/gustatory sensorial parameters. Linear discriminant models, based on subsets of 58 electronic tongue sensor signals, selected by the meta-heuristic simulated annealing variable selection algorithm, allowed the correct classification of olive oils according to the light exposition conditions and/or storage time (sensitivities and specificities for leave-one-out cross-validation: 8296 %). The predictive performance of the E-tongue approach was further evaluated using an external independent dataset selected using the KennardStone algorithm and, in general, better classification rates (sensitivities and specificities for external dataset: 67100 %) were obtained compared to those achieved using physicochemical or sensorial data. So, the work carried out is a proof-of-principle that the proposed electrochemical device could be a practical and versatile tool for, in a single and fast electrochemical assay, successfully discriminate olive oils with different storage times and/or exposed to different light conditions.The authors acknowledge the financial support from the strategic funding of UID/BIO/04469/2013 unit, from Project POCI-01-0145-FEDER-006984—Associate Laboratory LSRELCM funded by FEDER funds through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI)—and by national funds through FCT—Fundação para a Ciência e a Tecnologia and under the strategic funding of UID/BIO/04469/2013 unit. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/BD/104038/2014).info:eu-repo/semantics/publishedVersio

Culex pipiens, an Experimental Efficient Vector of West Nile and Rift Valley Fever Viruses in the Maghreb Region

West Nile fever (WNF) and Rift Valley fever (RVF) are emerging diseases causing epidemics outside their natural range of distribution. West Nile virus (WNV) circulates widely and harmlessly in the old world among birds as amplifying hosts, and horses and humans as accidental dead-end hosts. Rift Valley fever virus (RVFV) re-emerges periodically in Africa causing massive outbreaks. In the Maghreb, eco-climatic and entomologic conditions are favourable for WNV and RVFV emergence. Both viruses are transmitted by mosquitoes belonging to the Culex pipiens complex. We evaluated the ability of different populations of Cx. pipiens from North Africa to transmit WNV and the avirulent RVFV Clone 13 strain. Mosquitoes collected in Algeria, Morocco, and Tunisia during the summer 2010 were experimentally infected with WNV and RVFV Clone 13 strain at titers of 107.8 and 108.5 plaque forming units/mL, respectively. Disseminated infection and transmission rates were estimated 14–21 days following the exposure to the infectious blood-meal. We show that 14 days after exposure to WNV, all mosquito st developed a high disseminated infection and were able to excrete infectious saliva. However, only 69.2% of mosquito strains developed a disseminated infection with RVFV Clone 13 strain, and among them, 77.8% were able to deliver virus through saliva. Thus, Cx. pipiens from the Maghreb are efficient experimental vectors to transmit WNV and to a lesser extent, RVFV Clone 13 strain. The epidemiologic importance of our findings should be considered in the light of other parameters related to mosquito ecology and biology

Functions classification approach to generate reconfigurable fine-grain logic based on Ambipolar Independent Double Gate FET (Am-IDGFET)

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Growth of the blue mackerel Scomber scombrus in Tunisia using the otolith microstructure

This paper studies the age and the growth of male and female of the Tunisian blue mackerel Scomber scombrus during 2004-2006. The age was determined by interpreting and counting daily increments on the otoliths sagitta of 320 individuals sampled from landings caught by different gears specially by purse seine. The parameters of the Von Bertalanffy growth curve were estimated for sexes combined: L-f = 31.46(1 - e(-0.228) ((t+3.034))) (L-infinity = 31.46 cm, k = 0.228 per year, t(o) = -3.034 years); for male L-f = 27.43(1 - e (-0.422) ((t+1.747))) (L-infinity = 27.43 cm, k = 0.422 per year, t(o) = -1.747 years) and for female L-f = 31.70(1 - e(-0.227) ((t+2.196))) (L-infinity = 31.70 cm, k = 0.227 per year, t(o) = 22.916 years) for the whole study period. The difference between the growth of male and female is not significant. The relationship between length and weight shows a length growth faster than of the weight with parameters of the equation W-t = a*L-b; a = 9.89*10(-5) and b = 2.37 for the sexes combined

Comparison of Verilog-A compact modelling strategies for spintronic devices

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