Cross-dataset domain adaptation for the classification COVID-19 using chest computed tomography images

Detecting COVID-19 patients using Computed Tomography (CT) images of the lungs is an active area of research. Datasets of CT images from COVID-19 patients are becoming available. Deep learning (DL) solutions and in particular Convolutional Neural Networks (CNN) have achieved impressive results for the classification of COVID-19 CT images, but only when the training and testing take place within the same dataset. Work on the cross-dataset problem is still limited and the achieved results are low. Our work tackles the cross-dataset problem through a Domain Adaptation (DA) technique with deep learning. Our proposed solution, COVID19-DANet, is based on pre-trained CNN backbone for feature extraction. For this task, we select the pre-trained Efficientnet-B3 CNN because it has achieved impressive classification accuracy in previous work. The backbone CNN is followed by a prototypical layer which is a concept borrowed from prototypical networks in few-shot learning (FSL). It computes a cosine distance between given samples and the class prototypes and then converts them to class probabilities using the Softmax function. To train the COVID19-DANet model, we propose a combined loss function that is composed of the standard cross-entropy loss for class discrimination and another entropy loss computed over the unlabelled target set only. This so-called unlabelled target entropy loss is minimized and maximized in an alternative fashion, to reach the two objectives of class discrimination and domain invariance. COVID19-DANet is tested under four cross-dataset scenarios using the SARS-CoV-2-CT and COVID19-CT datasets and has achieved encouraging results compared to recent work in the literature.Comment: 31 pages, 15 figure

Gestion individuelle et collective du temps : comparaison entre situation manuelle et situation informatisée

Dans une perspective différentielle, l\u27objet de cet article est d\u27examiner en fonction de l\u27ex-périence professionnelle et dans les deux dimensions individuelle et collective, les conséquencesde l\u27informatisation sur les activités des opérateurs dans une situation de travail spéc fique • lagestion des tâches multiples Ces derniers y sont confrontés à une situation de charge de tra-vail caractérisée par une multiplicité de tâches de nature variée, de complexité diverse, dont ilsn\u27ontpas l\u27initiative Ils doivent alors gérer, dans différents cadres et milieux temporels, un en-semble de processus composés d\u27événements discontinus et indépendants les uns des autres, etdont l\u27occurrence peut créer des situations d\u27inter jérence et donc être source de perturbationsdans le déroulement du travail. Aussi, pour les compenser, les opérateurs mettent-ils en oeuvreplusieurs modes de contrôle temporel au cours de la réalisation de chacune des tâches., ils hié-rarchisent l\u27importance ou l\u27urgence des sollicitations, ils contrôlent la temporalité de leurs ac-tions, en réduisant les durées de corn unication ou en rétrécissant le réseau cle coopération,et ils synchronisent les actions collectives. La connaissance de ces stratégies de régulation estun préalable nécessaire à des mesures de conception et d\u27amélioration des situation

Evaluation of Liquefaction Potential of an Earth Dam Foundation Using In Situ Tests

This paper presents a case study of liquefaction potential assessment carried out under an earth dam foundation in Tunisia. An emphasis was made on the exploration of geotechnical conditions and the interpretation of field tests results collected before and after soil densification using the vibrocompaction technique. The assessment of soil liquefaction susceptibility was made using deterministic and probabilistic simplified procedures developed from several case histories. Conclusively, the obtained results show that before vibrocompaction the soil was prone to the liquefaction hazard. However, after vibrocompaction, a significant improvement of the soil resistance reduces the liquefaction potential of the sandy foundation. Indeed, before vibrocompaction, the factor of safety (FS) drops below 1 which means that the soil is susceptible for liquefaction. However, after vibrocompaction, the values of FS exceed the unit which justify the absence of liquefaction hazard in the dam foundation. In addition, before soil densification, the liquefaction evaluation using CPT-data shows probabilities values over 65 % which correspond to the classes of ‘’very likely’’ and ‘’Almost certain that will be liquefy’’ in the field case histories classification. The treated site presents low probability of liquefaction (less than 35%) indicating a low likelihood of liquefaction of the dam foundation

Apport de l’imagerie aéroportée par drone dans l’étude de l’interaction machine-sol-plante en culture de pomme de terre

L’usage des nouvelles technologies en agriculture de précision est une solution pour l’évolution démographique mondiale et ses besoins alimentaires face aux changements climatiques. L’expérimentation s’est basée sur le suivi du cycle végétatif d’une culture de pomme de terre de saison variété "Spunta" installée à différents interlignes, écartements et profondeurs de plantation par la technique d’imagerie RVB en utilisant un capteur sophistiqué embarqué sur drone. Afin d’améliorer le système de production et l’adapter au contexte du réchauffement climatique à travers les différents réglages sur la planteuse de pomme de terre, des indices de végétation ont été calculés à partir des images capturées tels que les indices GA, GGA, CSI, NGRDI et TGI indicateurs de la biomasse du végétal et son état de santé conduisant ainsi à une prise de décision correcte en termes d’apport nutritif et de traitement phytosanitaire. La combinaison suivante des facteurs interligne, inter-plant et profondeur de plantation respectifs IL = 90 cm, IP = 28 cm et P = 10 cm a révélé de meilleurs résultats en termes de tonnage et de calibre de pomme de terre

Factors determining Gekkotan (Reptilia, Sauria) distribution in Tunisia (North Africa)

Tunisian geckos count nine species (1 is insular relict, 1 is endemic, 2 are ubiquitous and 5 are enfeoffed). We aim to determine factors influencing their distributions. Surveys were founded on environmental divisions. Presence/absence data for 113 grids were analyzed using multivariate tools. 18 environmental variables were revealed and clustered into five factors to model species distributions. Established models were further projected on non-explored areas within Tunisian territory. The distribution of continental geckos follows an indirect bidirectional gradient; the South-northward one is physiologically stressful and the North-southward one is biologically stressful. Five biogeographic regions were established showing concordance with climatic and vegetation regionalization. The distribution of non-anthropophilic species is positively correlated to thermal amplitudes gradient. The distribution of anthropophilic taxa is positively correlated to agricultural land-use. Oasis, sebkhas and chotts are particular landscapes that disturb both distributions. Predicted areas follow the yielded distribution patterns despite some discrepancy for S. sthenodactylus. The niche characterizing shows that land use and altitude increase the probability of occurrence of H. turcicus and T. mauritanica. Alternatively, they decrease the probability of the presence of T. deserti, T. neglecta, T. tripolitanus and S. petrii. Models could also show that the absence of S. sthenodactylus in northern regions is attributed to high altitudes and cereal land-use. As to T. fascicularis, the displacement of the northern limits of its range is mostly attributed to an improvement of field investigations. Established model of its distribution shows a restricted area of probable occurrence in central Tunisia confirming its endemism

A first assessment of genetic variability in the Eurasian Stone-curlew Burhinus oedicnemus

The Eurasian Stone-curlew is a species of conservation concern in Europe. We investigate for the first time the extent of population structure among populations sampled from six geographical areas, representing four subspecies inhabiting the western part of the species’ distribution. Neither mitochondrial nor nuclear markers fully supported current subspecies boundaries. However, both markers support significant differentiation of the Canary Island populations from those sampled from the Mediterranean. Further work is needed to establish the taxonomic status of this potentially distinct Macaronesian taxon. More broadly, further genetic research is required to design and implement an effective conservation plan for this species

Methods to detect spatial biases in tracking studies caused by differential representativeness of individuals, populations and time

Este artículo contiene 20 páginas, 6 figuras, 4 tablas.Aim: Over the last decades, the study of movement through tracking data has grown exceeding the expectations of movement ecologists. This has posed new challenges, specifically when using individual tracking data to infer higher- level distributions (e.g. population and species). Sources of variability such as individual site fidelity (ISF), en-vironmental stochasticity over time, and space-use variability across species ranges must be considered, and their effects identified and corrected, to produce accurate estimates of spatial distribution using tracking data. Innovation: We developed R functions to detect the effect of these sources of vari-ability in the distribution of animal groups when inferred from individual tracking data. These procedures can be adapted for their use in most tracking datasets and tracking techniques. We demonstrated our procedures with simulated datasets and showed their applicability on a real-world dataset containing 1346 year- round migratory trips from 805 individuals of three closely related seabird species breeding in 34 colonies in the Mediterranean Sea and the Atlantic Ocean, spanning 10 years. We detected an effect of ISF in one of the colonies, but no effect of the environmental stochasticity on the distribution of birds for any of the species. We also identified among-colony variability in nonbreeding space use for one species, with significant effects of popu-lation size and longitude. Main conclusions: This work provides a useful, much- needed tool for researchers using animal tracking data to model species distributions or establish conservation measures. This methodology may be applied in studies using individual tracking data to accurately infer the distribution of a population or species and support the deline-ation of important areas for conservation based on tracking data. This step, designed to precede any analysis, has become increasingly relevant with the proliferation of studies using large tracking datasets that has accompanied the globalization process in science driving collaborations and tracking data sharing initiatives.We thank the following institutions for funding: EU H2020 pro-gramme through grant 634495; Seventh Framework Programme (Research Executive Agency) through Marie Curie Career Integration Grant 618841 (FP7-PEOPLE-2013- CIG); ESFRI LifeWatch Project; LIFE programme of the European Commission through projects LIFE10 NAT/MT090 and LIFE11 NAT/IT/000093; Ministerio de Ciencia e Innovación/Ministerio de Economia y Competitividad (Spain) through projects CGL2009- 11278/BOS, CGL2013-42585-P, C G L 2 0 1 3 - 4 2 2 0 3 - R , C G L 2 0 16 - 7 8 5 3 0 - R a n d C G L 2 0 17- 8 52 10 - P ; Organismo Autónomo de Parques Nacionales (Spain) through pro-ject 1248/2014; Fundação para a Ciência e a Tecnologia (MCTES, Portugal) through projects MARE-UID/MAR/04292/2019; IF/00502/2013/CP1186/CT0003, PTDC/BIA-ANM/3743/2014, PTDC/MAR-PRO/0929/2014, UID/AMB/50017/2019 and UIDP/50017/2020 + UIDB/50017/2020 (to CESAM); Office Français de la Biodiversité (France), through the Programme PACOMM, Natura2000 en mer; Hellenic Bird Ringing Centre; MSDEC (Malta). VMP was supported by pre-doctoral contract BES-2014- 068025 of the Spanish Ministerio de Industria, Economía y Competitividad; MM by grant SFRH/BPD/47047/2008 from the Portuguese Foundation for Science and Technology; JMRG by Ph.D. grant AP2009-2163 from the Spanish Ministerio de Educación; GDO and MMü by Ornis italica and by the Regione Siciliana and Assessorato Risorse Agricole e Alimentari thoriugh a grant to the Ringing Unit of Palermo; VHP by grant SFRH/BPD/85024/2012 from the Portuguese Foundation for Science and Technology; VN by grant SFRH/BPD/88914/2012 from the Portuguese Foundation for Science and Technology; and JN by the Spanish National Programme Ramón y Cajal (RYC-2015- 17809); GK and SX were partially funded by the Operational Program “Environment and Sustainable Development” (EPPERAA) of the National Strategic Reference Framework (NSRF) 2007-2013, co- financed by the ERDF and Greek EDP; FdF by a Ph.D. grant from the Coordination for the Improvement of Higher Education Personnel (CAPES—Brazilian government agency; Bex Process 1307/13-4); ZZ by a PhD grant from the University of Barcelona (APIF/2012); MCF by a PhD grant from the University of Barcelona; and RR by post-doctoral contracts of the PLEAMAR programme from MINECO and Fundación Biodiversidad (2017/2349), and Ministerio de Ciencia, in-novación y Universidades (RYC-2017- 22055). This publication is part of the project I+D+i/PID2020-117155GB-I00, funded by MCIN/ AEI/10.13039/501100011033.Peer reviewe