129 research outputs found
Sastav hrane i intenzitet ishrane lumbraka, Symphodus (Crenilabrus) tinca (Labridae), na juĆŸnim oblama Tunisa
The feeding habits of the peacock wrasse, Symphodus (Crenilabrus) tinca (Linnaeus, 1758), from the southern coast of Tunisia were investigated with respect to fish size and season. Stomach contents of 1334 specimens, 8.1-23.1 cm total length, were analyzed. Of the total, 1166 were empty (87.4%). This percentage varied over the year, with a maximum during the spawning period (May- July) and minimum in February and August. Crustaceans and mollusks constituted the main prey in both the small and large size classes. As fish grew, the proportion of isopods in the stomachs decreased and the proportion of shrimps and benthic organisms increased. Diet composition varied seasonally, with crustaceans the most important prey item in all seasons especially summer and autumn. Higher feeding activity in winter may be related to the reproductive cycle of the wrasse and the abundance of benthic organisms. Results indicate that the peacock wrasse feeds on a wide range of prey items and is an opportunistic predator.IstraĆŸivan je sastav hrane i intenzitet ishrane lumraka, Symphodus (Crenilabrus) tinca (Linnaeus, 1758) sakupljenog na juĆŸnim obalama Tunisa. Analiziran je sadrĆŸaj ĆŸeluca kod 1334 primjerka ukupne veliÄine 8.1-23.1 centimetara, od kojih je 1166 (87.4%) primjeraka imalo prazan ĆŸeludac. Intenzitet ishrane kolebao je tijekom godine od maksimuma za vrijeme sezone mrijeĆĄÄenja (svibanj-srpanj) do minimuma u veljaÄi i kolovozu. U hrani su prevladavali rakovi i mekuĆĄci svih veliÄina. Shodno veliÄini ustanovljeno je da je kod veÄih primjeraka zastupljenost izopoda u ishrani manja, dok su rakovi i bentiÄki organizmi viĆĄe zastupljeni. Intenzitet ishrane kolebao je prema godiĆĄnjem dobu, iako su rakovi bili najvaĆŸniji plijen tijekom cijele godine, a posebno u ljeto i jesen. ViĆĄi intenzitet hranjenja u zimskom razdoblju moĆŸe se pripisati periodu mrijesta lumbraka i poveÄanoj prisutnosti bentiÄkih organizama. Rezultati ukazuju da se lumbrak hrani ĆĄirokim rasponom plijena, te je oportunistiÄki predator
Phosphate and zinc transport and signalling in plants: toward a better understanding of their homeostasis interaction
Zn and Pi are essential elements for plant growth. Current understanding of the regulation of their homeostasis interaction and signalling cross-talk is presente
Estudio taxonĂłmico de Squalus megalops (Macleay, 1881) y Squalus blainvillei (Risso, 1827) (Chondrichthyes: Squalidae) en aguas de TĂșnez (MediterrĂĄneo central)
Two species of spurdog of the genus Squalus occur in the Gulf of GabĂšs (southern Tunisia, central Mediterranean): the longnose spurdog Squalus blainvillei (Risso, 1827) and a short-snout spurdog of the Squalus megalops-cubensis group. Morphometric and meristic data as well as a genetic analyses (DNA inter-simple sequence repeat markers and molecular barcoding methods) support the assignation of this short-snout spurdog to Squalus megalops (Macleay, 1881). Squalus megalops occurs commonly in temperate and tropical Australian waters, and is also thought to occur in the eastern Atlantic, southern Indian Ocean and western North Pacific although these records need to be confirmed. Our study confirms that it occurs in the Mediterranean Sea. Populations of both S. blainvillei and S. megalops are described based on Tunisian material.En el golfo de GabĂšs (sur de TĂșnez, MediterrĂĄneo central) se encuentran dos especies del gĂ©nero Squalus: el galludo Squalus blainvillei (Risso, 1827) y otra de morro mĂĄs corto perteneciente al grupo Squalus megalops-cubensis. Los datos morfomĂ©tricos y merĂsticos junto con el anĂĄlisis genĂ©tico (ADN Inter Simple Sequence Repeats markers y mĂ©todos moleculares Barcoding) apoyan la identificaciĂłn de esta Ășltima especie como Squalus megalops (Macleay, 1881). Squalus megalops se encuentra en aguas australianas templadas y tropicales, y se piensa que habita tambiĂ©n en el AtlĂĄntico este, en el ocĂ©ano Ăndico sur y en el PacĂfico noroccidental, aunque estos registros deben ser confirmados. Nuestro estudio confirma su presencia en el mar MediterrĂĄneo. La descripciĂłn tanto de S. blainvillei como de S. megalops estĂĄ basada en especĂmenes capturados en aguas tunecinas
SEASONAL VARIATION OF THE GLOBAL CHEMICAL COMPOSITION OF FISH: ANNULAR SEA BREAM DIPLODUS ANNULARIS (L, 1758)
Abstract Seasonal variation of the global chemical composition of the annular sea bream species of the coastal catch fish of the Gulf of Gabes (Tunisia) was studied between October 2007 and September 2008. The period of reproduction of Diplodus annularis occurs from April to June. This sexual maturity (RGS, RHS) is in strong correlation with the fat content. The fat content is negatively correlated with moisture content R= 0.83, P<10 ). The variance analysis of moisture, protein, fat and ash in the whole muscle shows that only the factor months has significant effect on the muscles chemical composition (P<10 )
Reproductive biology of Kleinâs sole, Synapturichthys kleinii (Actinopterygii: Pleuronectiformes: Soleidae), off Tunisian coast (central Mediterranean)
Background. Kleinâs sole, Synapturichthys kleinii (Risso, 1827), is a rare fish, included in the IUCN Red List as Data Deficient, and its biology is poorly known. Biological investigations of S. kleinii have been surprisingly rare in Tunisian waters. In the presently reported study, we investigated the reproductive period, size at first sexual maturity, and fecundity of S. kleinii along the Tunisian waters, with the aim of achieving the first complete and comprehensive description of the reproduction of this fish in the Mediterranean Sea. Materials and methods. A total of 294 specimens of S. kleinii were sampled over two years, off the Tunisian coasts. Sex ratio was estimated through the seasons of the year and the size classes. The stage of maturity was determined macroscopically only for females. Monthly gonadosomatic index (GSI), monthly hepatosomatic index (HSI), and condition factor (K) were calculated for males and females of S. kleinii. Size at first maturity was estimated only for females during the spawning season. Eighteen mature females at spawning stage were collected, weighed, and fixed in 4% formaldehyde solution for fecundity estimation. Results. Annual sex ratio showed significant differences between males and females. In specimens exceeding 27 cm in total length females outnumbered males significantly. The Kleinâs sole reproduction period started in October and ended in January. The gonadosomatic index reached highest values in November for females and males. Females attained sexual maturity at 20.53 cm total body length (TL). Total fecundity ranged from 3647 to 23 174 eggs. We found a low correlation coefficient between total fecundity and total length, but a high correlation coefficient between eviscerated weight and ovary weight. Conclusion. Our results constitute a preliminary baseline for monitoring changes in the biological indexes linked to the reproduction cycle and length at first sexual maturity of S. kleinii. The presently acquired data will enable biologists to assess the status of this fish and develop culture technology in natural waters and will be useful for the fishery biologists and conservation biologists, for successful development, management, production, and ultimate conservation of this favoured Tunisian food fish
Etude des interactions entre métaux lourds et phosphate chez les plantes : Aspects physiologiques et moléculaires
Durant cette derniĂšre dĂ©cennie, plusieurs voies de rĂ©gulation de lâhomĂ©ostasie de diffĂ©rents ions ont Ă©tĂ© identifiĂ©es chez les plantes. Le croisement des donnĂ©es de la littĂ©rature rĂ©vĂšle lâexistence de connexions insoupçonnĂ©es entre ces diffĂ©rentes voies de rĂ©gulation, limitant ainsi les perspectives dâapporter des solutions adaptĂ©es pour chaque Ă©lĂ©ment. En effet, la carence ou lâexcĂšs en un seul Ă©lĂ©ment cause une profonde perturbation de lâhomĂ©ostasie des autres Ă©lĂ©ments associĂ©s. Un exemple frappant illustrant lâinterconnexion entre lâhomĂ©ostasie des ions est celui qui concerne le phosphate inorganique (Pi), le zinc (Zn) et le fer (Fe). Dans ce contexte, lâobjectif de mon travail de thĂšse est de mieux comprendre les bases physiologiques et molĂ©culaires de lâinteraction entre le Pi, le Zn et le Fe chez les plantes. Trois plantes ont Ă©tĂ© utilisĂ©es dans ce travail : la plante modĂšle Arabidopsis thaliana, et deux plantes dâintĂ©rĂȘt agronomique, la laitue (Lactuca sativa) et le riz (Oryza sativa L.). Chez la laitue, mes rĂ©sultats montrent lâexistence dâune base gĂ©nĂ©tique pour la co-rĂ©gulation de lâhomĂ©ostasie du Pi et de celle du Zn chez les deux variĂ©tĂ©s de laitue utilisĂ©es, toute en y rĂ©vĂ©lant un comportement contrastĂ©. Chez le riz, jâai prouvĂ© Ă©galement lâexistence d'une base gĂ©nĂ©tique pour les interactions non seulement entre les homĂ©ostasies du Pi, et celle du Zn et mais aussi avec celle du Fe, et j'ai dĂ©montrĂ© un rĂŽle important du transporteur du Pi OsPHO1;1 dans ce processus. Enfin, en utilisant lâapproche de gĂ©nĂ©tique dâassociation, de nouveaux gĂšnes impliquĂ©s dans les interactions homĂ©ostatiques Pi-Zn ont Ă©tĂ© caractĂ©risĂ©s chez Arabidopsis
SystÚme embarqué de fusion multi-capteurs pour la détection et le suivi d'obstacles statiques et dynamiques
This thesis is a part of an Industrial Agreements for Training through Research (Cifre) in partnership with NAVYA Technology, for autonomous vehicles. Navya designed the shuttle ARMA which used proprioceptive and exteroceptive sensors for localization (SLAM : Simultaneous Localization and Mapping) as well as the detection and tracking of obstacles (DTMO : Detection and Tracking of Moving Objects). In this thesis, we were interested in the DTMO task which aimed to detect objects around the vehicle to avoid collisions and to ensure secure and reliable autonomous driving. Our contributions through this thesis were as follows : (1) We proposed an extrinsic calibration methodology between a single-vision system and a 2D LIDAR sensor. We presented a complete implementable toolchain to extract the co-features for both types of sensors. We validated this contribution on the autonomous shuttle ARMA. (2) Since an autonomous vehicle is located in an uncertain environment, we chose the belief theory (or Dempster-Shafer) to model and manage knowledge and uncertainties. We proposed a camera-radar fusion methodology to improve the reliability of detection and classification for both pedestrians and vehicles. (3) Our implementation target is a 100% electric autonomous shuttle. So, it was necessary to use an embedded platform to respect constraints such as power consumption. In this contribution, FPGA was our solution to host the intensive processing of autonomous vehicle perception algorithms. We presented an embedded solution based on heterogeneous System On Chip (Zynq-7000) to fuse the positions of obstacles detected by a stereoscopic camera and a LIDAR using the Bayesian approach.Ce mĂ©moire sâinscrit dans le cadre dâune Convention industrielle de formation par la recherche (Cifre) en partenariat avec lâentreprise NAVYA Technology, spĂ©cialisĂ©e dans la fabrication des vĂ©hicules Ă©lectriques autonomes. La technologie de la navette ARMA conçue par Navya, utilise des capteurs proprioceptifs et extĂ©roceptifs pour la localisation (SLAM : Simultaneous Localization and Mapping) ainsi que pour la dĂ©tection et le suivi dâobstacles statiques et dynamiques (DTMO : Detection and Tracking of Moving Objects). Dans cette thĂšse, nous nous intĂ©ressons Ă la fonctionnalitĂ© DTMO qui a pour objectif de dĂ©tecter les objets autour du vĂ©hicule afin dâĂ©viter les collisions et assurer une conduite autonome, sĂ©curisĂ©e et fiable. Nos contributions Ă travers cette thĂšse sont les suivantes : (1) Nous avons proposĂ© une mĂ©thodologie de calibration extrinsĂšque entre un systĂšme mono-vision et un capteur LIDAR 2D. Nous avons dĂ©veloppĂ© un environnement de calibration qui inclut lâextraction des caractĂ©ristiques de la mire de calibration par les deux capteurs. Nous avons validĂ© cette contribution sur la navette autonome ARMA. (2) Ătant donnĂ© quâun vĂ©hicule autonome se situe dans un environnement incertain, nous avons choisi la thĂ©orie de croyance (ou Dempster Shafer) et ses outils pour modĂ©liser les connaissances et les incertitudes. Nous avons mis Ă contribution une approche de fusion entre une camĂ©ra et un radar dans le but dâamĂ©liorer la fiabilitĂ© de dĂ©tection et de classification des piĂ©tons et des vĂ©hicules. Pour classifier les obstacles, les connaissances sont dĂ©duites Ă partir du paramĂštre Radar Cross Section (RCS) fourni par le radar, qui reflĂšte la nature de lâobstacle dĂ©tectĂ©, et la classification effectuĂ©e par la camĂ©ra. (3) Dans une troisiĂšme contribution, nous avons explorĂ© lâespace de conception dâune plateforme embarquĂ©e dĂ©diĂ©e Ă la dĂ©tection dâobstacles. Parmi les technologies dâaccĂ©lĂ©ration du traitement, nous avons choisi la solution FPGA permettant dâoffrir une puissance de calcul performante, par le moyen de ses ressources reconfigurables, avec une faible consommation de puissance tout en garantissant un coĂ»t maitrisĂ©. Nous avons prĂ©sentĂ© une conception dâune plateforme embarquĂ©e Ă base dâun systĂšme sur puce hĂ©tĂ©rogĂšne (Zynqâ7000) pour fusionner les postions dâobstacles dĂ©tectĂ©s par une camĂ©ra stĂ©rĂ©oscopique et un LIDAR en utilisant lâapproche bayĂ©sienne
Multi-sensor embeded system for object detection
Ce mĂ©moire sâinscrit dans le cadre dâune Convention industrielle de formation par la recherche (Cifre) en partenariat avec lâentreprise NAVYA Technology, spĂ©cialisĂ©e dans la fabrication des vĂ©hicules Ă©lectriques autonomes. La technologie de la navette ARMA conçue par Navya, utilise des capteurs proprioceptifs et extĂ©roceptifs pour la localisation (SLAM : Simultaneous Localization and Mapping) ainsi que pour la dĂ©tection et le suivi dâobstacles statiques et dynamiques (DTMO : Detection and Tracking of Moving Objects). Dans cette thĂšse, nous nous intĂ©ressons Ă la fonctionnalitĂ© DTMO qui a pour objectif de dĂ©tecter les objets autour du vĂ©hicule afin dâĂ©viter les collisions et assurer une conduite autonome, sĂ©curisĂ©e et fiable. Nos contributions Ă travers cette thĂšse sont les suivantes : (1) Nous avons proposĂ© une mĂ©thodologie de calibration extrinsĂšque entre un systĂšme mono-vision et un capteur LIDAR 2D. Nous avons dĂ©veloppĂ© un environnement de calibration qui inclut lâextraction des caractĂ©ristiques de la mire de calibration par les deux capteurs. Nous avons validĂ© cette contribution sur la navette autonome ARMA. (2) Ătant donnĂ© quâun vĂ©hicule autonome se situe dans un environnement incertain, nous avons choisi la thĂ©orie de croyance (ou Dempster Shafer) et ses outils pour modĂ©liser les connaissances et les incertitudes. Nous avons mis Ă contribution une approche de fusion entre une camĂ©ra et un radar dans le but dâamĂ©liorer la fiabilitĂ© de dĂ©tection et de classification des piĂ©tons et des vĂ©hicules. Pour classifier les obstacles, les connaissances sont dĂ©duites Ă partir du paramĂštre Radar Cross Section (RCS) fourni par le radar, qui reflĂšte la nature de lâobstacle dĂ©tectĂ©, et la classification effectuĂ©e par la camĂ©ra. (3) Dans une troisiĂšme contribution, nous avons explorĂ© lâespace de conception dâune plateforme embarquĂ©e dĂ©diĂ©e Ă la dĂ©tection dâobstacles. Parmi les technologies dâaccĂ©lĂ©ration du traitement, nous avons choisi la solution FPGA permettant dâoffrir une puissance de calcul performante, par le moyen de ses ressources reconfigurables, avec une faible consommation de puissance tout en garantissant un coĂ»t maitrisĂ©. Nous avons prĂ©sentĂ© une conception dâune plateforme embarquĂ©e Ă base dâun systĂšme sur puce hĂ©tĂ©rogĂšne (Zynqâ7000) pour fusionner les postions dâobstacles dĂ©tectĂ©s par une camĂ©ra stĂ©rĂ©oscopique et un LIDAR en utilisant lâapproche bayĂ©sienne.This thesis is a part of an Industrial Agreements for Training through Research (Cifre) in partnership with NAVYA Technology, for autonomous vehicles. Navya designed the shuttle ARMA which used proprioceptive and exteroceptive sensors for localization (SLAM : Simultaneous Localization and Mapping) as well as the detection and tracking of obstacles (DTMO : Detection and Tracking of Moving Objects). In this thesis, we were interested in the DTMO task which aimed to detect objects around the vehicle to avoid collisions and to ensure secure and reliable autonomous driving. Our contributions through this thesis were as follows : (1) We proposed an extrinsic calibration methodology between a single-vision system and a 2D LIDAR sensor. We presented a complete implementable toolchain to extract the co-features for both types of sensors. We validated this contribution on the autonomous shuttle ARMA. (2) Since an autonomous vehicle is located in an uncertain environment, we chose the belief theory (or Dempster-Shafer) to model and manage knowledge and uncertainties. We proposed a camera-radar fusion methodology to improve the reliability of detection and classification for both pedestrians and vehicles. (3) Our implementation target is a 100% electric autonomous shuttle. So, it was necessary to use an embedded platform to respect constraints such as power consumption. In this contribution, FPGA was our solution to host the intensive processing of autonomous vehicle perception algorithms. We presented an embedded solution based on heterogeneous System On Chip (Zynq-7000) to fuse the positions of obstacles detected by a stereoscopic camera and a LIDAR using the Bayesian approach
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