Louis M.,CNRS Chizé Center for Biological Studies |
Louis M.,CNRS Coastal and Marine Environment Laboratory |
Louis M.,GECC Groupe dEtude des Cetaces du Cotentin |
Viricel A.,CNRS Coastal and Marine Environment Laboratory |
And 19 more authors.
Molecular Ecology | Year: 2014
Despite no obvious barrier to gene flow, historical environmental processes and ecological specializations can lead to genetic differentiation in highly mobile animals. Ecotypes emerged in several large mammal species as a result of niche specializations and/or social organization. In the North-West Atlantic, two distinct bottlenose dolphin (Tursiops truncatus) ecotypes (i.e. 'coastal' and 'pelagic') have been identified. Here, we investigated the genetic population structure of North-East Atlantic (NEA) bottlenose dolphins on a large scale through the analysis of 381 biopsy-sampled or stranded animals using 25 microsatellites and a 682-bp portion of the mitochondrial control region. We shed light on the likely origin of stranded animals using a carcass drift prediction model. We showed, for the first time, that coastal and pelagic bottlenose dolphins were highly differentiated in the NEA. Finer-scale population structure was found within the two groups. We suggest that distinct founding events followed by parallel adaptation may have occurred independently from a large Atlantic pelagic population in the two sides of the basin. Divergence could be maintained by philopatry possibly as a result of foraging specializations and social organization. As coastal environments are under increasing anthropogenic pressures, small and isolated populations might be at risk and require appropriate conservation policies to preserve their habitats. While genetics can be a powerful first step to delineate ecotypes in protected and difficult to access taxa, ecotype distinction should be further documented through diet studies and the examination of cranial skull features associated with feeding. © 2014 John Wiley & Sons Ltd.
Xargay E.,University of Illinois at Urbana - Champaign |
Kaminer I.,Naval Postgraduate School, Monterey |
Pascoal A.,University of Lisbon |
Pascoal A.,Laboratory of Robotics and Systems in Engineering and Science |
And 6 more authors.
Journal of Guidance, Control, and Dynamics | Year: 2013
This paper addresses the problem of steering a fleet of unmanned aerial vehicles along desired three-dimensional paths while meeting stringent spatial and temporal constraints. A representative example is the challenging mission scenario where the unmanned aerial vehicles are tasked to cooperatively execute collision-free maneuvers and arrive at their final destinations at the same time. In the proposed framework, the unmanned aerial vehicles are assigned nominal spatial paths and speed profiles along those, and then the vehicles are requested to execute cooperative path following, rather than open loop trajectory tracking maneuvers. This strategy yields robust behavior against external disturbances by allowing the unmanned aerial vehicles to negotiate their speeds along the paths in response to information exchanged over the supporting communications network. The paper considers the case where the graph that captures the underlying time-varying communications topology is disconnected during some interval of time or even fails to be connected at all times. Conditions are given under which the cooperative path-following closed-loop system is stable. Flight test results of a coordinated road-search mission demonstrate the efficacy of the multi-vehicle cooperative control framework developed in the paper. Copyright © 2012 by E. Xargay, I. Kaminer,A. Pascoal, N. Hovakimyan,V. Dobrokhodov, V. Cichella, A. P. Aguiar, and R. Ghabcheloo. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.
Afonso P.,University of The Azores |
Afonso P.,Laboratory of Robotics and Systems in Engineering and Science |
Porteiro F.M.,University of The Azores |
Porteiro F.M.,Laboratory of Robotics and Systems in Engineering and Science |
And 9 more authors.
Journal of Fish Biology | Year: 2013
Seven coastal fish species are newly reported for the remote north Atlantic archipelago of the Azores: Mediterranean sand eel Gymnammodytes cicerelus, bar jack Caranx ruber, two-banded seabream Diplodus vulgaris, bastard grunt Pomadasys incisus, unicorn leatherjacket filefish Aluterus scriptus and longspined porcupinefish Diodon holacanthus. The occurrence is also confirmed for 19 species that had been hitherto cited occasionally for the region, totalling a list of two elasmobranchs and 23 teleosts. Diplodus vulgaris, which appears to have recently colonized the islands, as well as roughtail stingray Dasyatis centroura and golden grey mullet Liza aurata, re-cited based on new records, are frequent or common coastal species in the Azores. The remaining 22 species, exceptional or rare in the region, are of tropical or subtropical affinity and find their northernmost distribution limit within the central and north-east Atlantic Ocean precisely in the Azores. This biogeographical pattern contrasts with that of the Azorean coastal fish community and suggests a tropicalization process in the region in line with previous findings of similar patterns across the north-east Atlantic Ocean and the Mediterranean Sea. These novel data from the most isolated archipelago of the North Atlantic Ocean, located in a biogeographic boundary area where colonization opportunities are reduced, reinforce the need for long-term monitoring programmes of coastal fish communities and, in particular, of indicator species groups to improve understanding of the effects of climate change on marine communities. © 2013 The Fisheries Society of the British Isles.
Marino A.,University of Salerno |
Antonelli G.,University of Cassino and Southern Lazio |
Aguiar A.P.,University of Porto |
Aguiar A.P.,Laboratory of Robotics and Systems in Engineering and Science |
And 2 more authors.
IEEE Transactions on Control Systems Technology | Year: 2014
This brief presents a decentralized coordinated strategy for multirobot patrolling missions. Patrolling is here interpreted within the framework of the sampling problem. To be applied in practice, several realistic constraints and the time/spatial variance of the information are explicitly considered. The proposed approach is well rooted in the concepts of Voronoi tessellations and Gaussian Processes. Each robot, based only on local information, computes the next point to visit according to a given performance criteria. Numerical simulations and experiments involving three autonomous marine surface robots in a harbor scenario at the Parque Expo site in Lisbon, Portugal, are presented. © 2014 IEEE.