Éditeur(s) : INRA : Institut National de la Recherche Agronomique Université des Antilles. Service commun de la documentation
Extrait de : 52e congrès annuel de la Société caribéenne des plantes alimentaires / 52nd annual meeting of the Caribbean food crops society (CFCS), du 10 au 16 juillet 2016. INRA, CFCS
Description : In the new context of the agro-ecological transition, present agricultural systems will have to produce more and better in a more constraint world. Mixed crop livestock systems (MCLS) represent sound alternative ways to progressively achieve these goals through crop-livestock integration (CLI). CLI exploits the synergies between cropping and livestock systems through organic fertilization with manure or plant association, use of crop residues to feed livestock, .... It offers many opportunities to improve productivity, as well as to increase resource use efficiency and improve the resilience of the whole farming system. In the scientific literature, authors advocate the interest of MLCS and CLI, based on theoretical considerations, modelling and empirical evidence from local case studies. But these studies do not clearly identify the respective roles of diversity of activities and CLI management practices in improving performances at the level of the whole farming system. Our aim was thus to assess CLI at farm scale in a range of MCLS and to explain farm performances by analyzing the combination of activities and the level of integration. We conducted our analyses in Guadeloupe, (French West Indies), where MCLS and CLI are complex but important challenges for local agricultural. In order to analyze CLI in a holistic and systemic way, we applied a method traditionally used in ecology, ecological network analysis, to study the structure, functioning and performance of agrosystems. This method was implemented on a range of Guadeloupian MCLS where CLI practices where identified. Nitrogen was retained to conduct the analysis due to its central role for both animal and vegetal productions. The ENA method allows an estimation of productivity, resilience, efficiency, productivity and self- sufficiency of the flows network. Our results show that 1/ efficiency and resilience appear correlated to the complexity and intensity of the network of flows; 2/ efficiency and resiliency are positively correlated when we consider them in terms of N flows; 3/ in the Guadeloupian context, CLI concerns mainly specific practices, as feeding pigs with a wide range of crop residues and organic fertilization of small market gardens and plots used to grow tubers. But at whole system level, CLI remains rare and mainly depends on conventional management practices as mineral fertilization and animal complementation of some farming activities as sugar cane, cattle breeding and banana. Moreover, the combination of productions implemented determines the potential of CLI and related performances linked to relative N efficiency of each production. Consequently, performance and especially efficiency and self-sufficiency depend more on the nature of the activity than on CLI management practices. There is still a gap between theoretical studies and CLI in practice, even though CLI is more complicated than simple flows and provides other services and functions. Dans le nouveau contexte de la transition agro-écologique, les systèmes agricoles actuels devront produire plus et les améliorer dans plus de monde de contrainte. Les systèmes mélangés de bétail de culture (MCLS) représentent des manières alternatives saines d'atteindre progressivement ces buts par l'intégration de culture-bétail (CLI). Le CLI exploite les synergies entre l'emblavage et les systèmes de bétail par la fertilisation organique avec l'association d'engrais ou d'usine, utilisation des résidus de culture d'alimenter le bétail,?. Il donne beaucoup d'occasions d'améliorer la productivité, aussi bien que d'augmenter l'efficacité d'utilisation de ressource et d'améliorer la résilience du système d'exploitation agricole entier. Dans la littérature scientifique, les auteurs préconisent l'intérêt de MLCS et de CLI, basé sur des considérations théoriques, modeler et des preuves empiriques des études de cas locales. Mais ces études n'identifient pas clairement les rôles respectifs de la diversité des activités et des pratiques de gestion de CLI en améliorant des interprétations au niveau du système d'exploitation agricole entier. Notre but était ainsi d'évaluer le CLI à l'échelle de ferme dans une gamme de MCLS et d'expliquer des interprétations de ferme en analysant la combinaison des activités et du niveau de l'intégration. Nous avons réalisé nos analyses en Guadeloupe, (des Antilles françaises), où MCLS et le CLI sont des défis complexes mais importants pour agricole local. Afin d'analyser le CLI d'une manière holistique et systémique, nous avons appliqué une méthode traditionnellement employée en écologie, analyse réseau écologique, pour étudier la structure, le fonctionnement et l'interprétation des agrosystems. Cette méthode a été appliquée sur une chaîne de Guadeloupian MCLS où des pratiques en matière de CLI où identifiée. L'azote a été maintenu pour réaliser l'analyse due à son rôle central pour les productions animales et végétales. La méthode d'ENA permet une évaluation de la productivité, de la résilience, de l'efficacité, de la productivité et de l'autosuffisance du réseau d'écoulements. Nos résultats prouvent que 1 efficacités et résiliences semblent corrélées avec la complexité et l'intensité du réseau des écoulements ; 2 efficacité et élasticité sont franchement corrélés quand nous les considérons en termes d'écoulements de N ; 3 dans le contexte de Guadeloupian, CLI concerne principalement des pratiques spécifiques, en tant que les porcs de alimentation par un large éventail de résidus de culture et de fertilisation organique de petits jardins du marché et complots employés pour cultiver des tubercules. Mais à au niveau système entier, le CLI demeure rare et dépend principalement des pratiques de gestion conventionnelles en tant que complémentation minérale de fertilisation et d'animal de quelques activités agricoles comme canne à sucre, élevage et banane. D'ailleurs, la combinaison des productions mises en application détermine le potentiel du CLI et des interprétations relatives liés à l'efficacité relative de N de chaque production. En conséquence, l'interprétation et particulièrement l'efficacité et l'autosuffisance dépendent davantage de la nature de l'activité que sur des pratiques de gestion de CLI. Il y a toujours un espace entre les études et le CLI théoriques dans la pratique, quoique le CLI soit plus compliqué que des écoulements simples et fournisse d'autres services et fonctions.
Siècle(s) traité(s) : 21
Droits : CC-BY-NC-ND - Attribution - Pas d'utilisation commerciale - Pas de modification
Permalien : http://www.manioc.org/fichiers/V16247
V16247

Éditeur(s) : HAL CCSD
Résumé : International audience
Traditional network generation models aim to replicate global structural properties observed on various real-world networks (power law degree distribution, short average distance, community structure, etc.) through synthetic link formation mechanisms such as triadic closure or preferential attachment. Nowadays the large amount of data available allows to study more precisely the link formation processes and to compare the models to real situations. In this work, we analyse the communication activities of the users of a mobile telephony operator for studying the link formation process. The communications emitted and received by users are strong indicators for understanding the underlying mechanisms of the link formation process and highlighting how user attributes correlate with the formation process in such a network. In a first study conducted at a global level we show that the traditional mechanisms commonly used in network generation models are not the main link formation mechanisms involved in this network. In a second study, we analyse more precisely the link formation process by searching for correlations between some user attributes and the formation of the new links. These results provide valuable guidelines to the design of more realistic generation models taking into account network structure and node attributes.
IEEE International Conference on Research Challenges in Information Science (RCIS)
Marrakesh, Morocco

hal-01312314
https://hal.archives-ouvertes.fr/hal-01312314
DOI : 10.1109/RCIS.2014.6861065

Éditeur(s) : HAL CCSD
Résumé : 6 pages
In a Spiking Neural Networks (SNN), spike emissions are sparsely and irregularly distributed both in time and in the network architecture. Since a current feature of SNNs is a low average activity, efficient implementations of SNNs are usually based on an Event-Driven Simulation (EDS). On the other hand, simulations of large scale neural networks can take advantage of distributing the neurons on a set of processors (either workstation cluster or parallel computer). This article presents DAMNED, a large scale SNN simulation framework able to gather the benefits of EDS and parallel computing. Two levels of parallelism are combined: Distributed mapping of the neural topology, at the network level, and local multithreaded allocation of resources for simultaneous processing of events, at the neuron level. Based on the causality of events, a distributed solution is proposed for solving the complex problem of scheduling without synchronization barrier.
https://hal.archives-ouvertes.fr/hal-00015137

hal-00015137
https://hal.archives-ouvertes.fr/hal-00015137
https://hal.archives-ouvertes.fr/hal-00015137v2/document
https://hal.archives-ouvertes.fr/hal-00015137/file/hal_damned.pdf
ARXIV : cs.NE/0512018

Résumé : Ifremer launched and coordinated the development of a strategy for the REBENT network (REseau BENThique) in 2000 to monitor the aftermath of the "Erika" oil spill in December 1999. Its aim is to provide consistent baseline knowledge about coastal benthic habitats and constitute a monitoring tool to detect changes at various scales over time and space. Sector-based seabed habitat mapping in shallow water (< 50 m deep), is currently being conducted throughout Brittany's coastal waters through a combination of geoacoustic marine systems and ground-truthing using biological grab sampling and seabed observations. Sedimentological and biological results on Glenan area emphasize a great diversity of subtidal habitats and marine species recognized. Sidescan imagery accentuates the complexity of the communities structure in a marine environment distinguished by strong and regulary roughness of the sea. Maerl biocenose is present at the nord-east of the archipelago. Progressively it gives way to mud sediment colonized by Amphiura filiformis and Haploops in the deeper channel. To the west and the south, substratum types are more coarse, occasionally mobiles, composed of essentially sand community with Nephtys and gravelly sand community with Branchiostoma lanceolatum.
Le Rebent (Réseau benthique), initié en 2000 à la suite de la catastrophe de l'Erika, a pour objectif de suivre les habitats benthiques côtiers et de détecter les changements à différentes échelles de temps et d'espace. L'approche sectorielle dans les petits fonds (< 50 m) des côtes bretonnes combine, des moyens de prospection acoustique, afin de délimiter les principaux types de substrats, avec des prélèvements et des observations biologiques pour caractériser les peuplements macrobenthiques. Les résultats des analyses sédimentologiques et faunistiques montrent autour de l'archipel des Glénan, une grande diversité d'habitats et d'espèces reconnues. L'imagerie acoustique fait ressortir la complexité de leur structuration dans un environnement marin soumis à de fortes et régulières périodes d'agitation. La biocénose de maërl occupe le nord-est de l'archipel. Elle laisse place progressivement aux sédiments envasés à Amphiura filiformis et aux vases à Haploops dans le fond du chenal. A l'ouest et au sud, les subtrats sont plus grossiers, essentiellement sableux à Nephtys et sablo-graveleux à Branchiostoma lanceolatum, épisodiquement mobiles.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2006/rapport-2301.pdf
http://archimer.ifremer.fr/doc/2006/sup-2301.pdf
http://archimer.ifremer.fr/doc/00000/2301/

Éditeur(s) : Amer Geophysical Union
Résumé : After the January 12, 2010, Haiti earthquake, we deployed a mainly offshore temporary network of seismologic stations around the damaged area. The distribution of the recorded aftershocks, together with morphotectonic observations and mainshock analysis, allow us to constrain a complex fault pattern in the area. Almost all of the aftershocks have a N-S compressive mechanism, and not the expected left-lateral strike-slip mechanism. A first-order slip model of the mainshock shows a N264 degrees E north-dipping plane, with a major left-lateral component and a strong reverse component. As the aftershock distribution is sub-parallel and close to the Enriquillo fault, we assume that although the cause of the catastrophe was not a rupture along the Enriquillo fault, this fault had an important role as a mechanical boundary. The azimuth of the focal planes of the aftershocks are parallel to the north-dipping faults of the Transhaitian Belt, which suggests a triggering of failure on these discontinuities. In the western part, the aftershock distribution reflects the triggering of slip on similar faults, and/or, alternatively, of the south-dipping faults, such the Trois-Baies submarine fault. These observations are in agreement with a model of an oblique collision of an indenter of the oceanic crust of the Southern Peninsula and the sedimentary wedge of the Transhaitian Belt: the rupture occurred on a wrench fault at the rheologic boundary on top of the under-thrusting rigid oceanic block, whereas the aftershocks were the result of the relaxation on the hanging wall along pre-existing discontinuities in the frontal part of the Transhaitian Belt. Citation: Mercier de Lepinay, B., et al. (2011), The 2010 Haiti earthquake: A complex fault pattern constrained by seismologic and tectonic observations, Geophys. Res. Lett., 38, L22305, doi:10.1029/2011GL049799.
Geophysical Research Letters (0094-8276) (Amer Geophysical Union), 2011-11 , Vol. 38 , N. L22305 , P. 7 p.

Droits : 2011 by the American Geophysical Union
http://archimer.ifremer.fr/doc/00054/16557/14071.pdf
DOI:10.1029/2011GL049799
http://archimer.ifremer.fr/doc/00054/16557/

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
BackgroundFor a long time biologists and linguists have been noticing surprising similarities between the evolution of life forms and languages. Most of the proposed analogies have been rejected. Some, however, have persisted, and some even turned out to be fruitful, inspiring the transfer of methods and models between biology and linguistics up to today. Most proposed analogies were based on a comparison of the research objects rather than the processes that shaped their evolution. Focusing on process-based analogies, however, has the advantage of minimizing the risk of overstating similarities, while at the same time reflecting the common strategy to use processes to explain the evolution of complexity in both fields.ResultsWe compared important evolutionary processes in biology and linguistics and identified processes specific to only one of the two disciplines as well as processes which seem to be analogous, potentially reflecting core evolutionary processes. These new process-based analogies support novel methodological transfer, expanding the application range of biological methods to the field of historical linguistics. We illustrate this by showing (i) how methods dealing with incomplete lineage sorting offer an introgression-free framework to analyze highly mosaic word distributions across languages; (ii) how sequence similarity networks can be used to identify composite and borrowed words across different languages; (iii) how research on partial homology can inspire new methods and models in both fields; and (iv) how constructive neutral evolution provides an original framework for analyzing convergent evolution in languages resulting from common descent (Sapir’s drift).ConclusionsApart from new analogies between evolutionary processes, we also identified processes which are specific to either biology or linguistics. This shows that general evolution cannot be studied from within one discipline alone. In order to get a full picture of evolution, biologists and linguists need to complement their studies, trying to identify cross-disciplinary and discipline-specific evolutionary processes. The fact that we found many process-based analogies favoring transfer from biology to linguistics further shows that certain biological methods and models have a broader scope than previously recognized. This opens fruitful paths for collaboration between the two disciplines.
ISSN: 1745-6150

Droits : http://creativecommons.org/licenses/by/
hal-01378396
http://hal.upmc.fr/hal-01378396
http://hal.upmc.fr/hal-01378396/document
http://hal.upmc.fr/hal-01378396/file/unity.pdf
DOI : 10.1186/s13062-016-0145-2

Éditeur(s) : HAL CCSD
Résumé : International audience
In the network modeling area, the most widely used definition of a "pattern" is that of a subgraph, a notion that considers only the network topological structure. While this definition has been very useful for extracting subgraphs frequently found in a network or a set of networks, it does not take into account the node attributes, an intrinsic component of social networks that often provides relevant information on the role or the position of a node in a network. In this paper, we propose a novel approach for extracting frequent patterns in social networks, called frequent link mining, based on the search for particular patterns that combine information on both network structure and node attributes. This kind of patterns, that we call frequent links, provides knowledge on the groups of nodes connected in the social network. In this article, we detail the method proposed for extracting frequent links and discuss its flexibility and its complexity. We demonstrate the efficiency of our solution by carrying out qualitative and quantitative studies.
Advances in Database (Weston, Conn.)s and Information Systems
Poznań, Poland

hal-00767050
https://hal.archives-ouvertes.fr/hal-00767050
DOI : 10.1007/978-3-642-33074-2_28

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
These last years, many analysis methods have been proposed to extract knowledge from social networks. As for the traditional data mining domain, these network-based approaches can be classified according to two main families. The approaches based on predictive modelling, which encompass the techniques that analyse current and historical facts to make predictive assumptions about future or unknown events. The approaches based on descriptive modelling, which cover the set of techniques that aim to summarize the data by identifying some relevant features in order to describe how things organize and actually work. In this paper, we review the main descriptive modelling methods of social networks and show for each of them the resulting useful knowledge on a running example. We particularly emphasize on the most recent methods that combine information available on both the network structure and the node attributes in order to provide original description models taking into account the context.
EISSN: 1877-0509

hal-01312383
https://hal.univ-antilles.fr/hal-01312383
DOI : 10.1016/j.procs.2015.05.505

Éditeur(s) : HAL CCSD Oxford University Press (OUP)
Résumé : International audience
BACKGROUND: Mammalian spermatogenesis is a process that involves a complex expression program in both somatic and germ cells present in the male gonad. A number of studies have attempted to define the transcriptome of male meiosis and gametogenesis in rodents and primates. Few human transcripts, however, have been associated with testicular somatic cells and germ cells at different post-natal developmental stages and little is known about their level of germline-specificity compared with non-testicular tissues. METHODS: We quantified human transcripts using GeneChips and a total of 47 biopsies from prepubertal children diagnosed with undescended testis, infertile adult patients whose spermatogenesis is arrested at consecutive stages and fertile control individuals. These results were integrated with data from enriched normal germ cells, non-testicular expression data, phenotype information, predicted regulatory DNA-binding motifs and interactome data. RESULTS: Among 3580 genes for which we found differential transcript concentrations in somatic and germ cells present in human testis, 933 were undetectable in 45 embryonic and adult non-testicular tissues, including many that were corroborated at protein level by published gene annotation data and histological high-throughput protein immunodetection assays. Using motif enrichment analyses, we identified regulatory promoter elements likely involved in germline development. Finally, we constructed a regulatory disease network for human fertility by integrating expression signals, interactome information, phenotypes and functional annotation data. CONCLUSIONS: Our results provide broad insight into the post-natal human testicular transcriptome at the level of cell populations and in a global somatic tissular context. Furthermore, they yield clues for genetic causes of male infertility and will facilitate the identification of novel cancer/testis genes as targets for cancer immunotherapies.
ISSN: 0268-1161

hal-00877243
https://hal.archives-ouvertes.fr/hal-00877243
DOI : 10.1093/humrep/des301
PUBMED : 22926843

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Cell proliferation is a hallmark of cancer and depends on complex signaling networks that are chiefly supported by protein kinase activities. Therapeutic strategies have been used to target specific kinases but new methods are required to identify combined targets and improve treatment. Here, we propose a small interfering RNA genetic screen and an integrative approach to identify kinase networks involved in the proliferation of cancer cells. The functional siRNA screen of 714 kinases in HeLa cells identified 91 kinases implicated in the regulation of cell growth, most of them never being reported in previous whole-genome siRNA screens. Based on gene ontology annotations, we have further discriminated between two classes of kinases that, when suppressed, result in alterations of the mitotic index and provoke cell-cycle arrest. Extinguished kinases that lead to a low mitotic index mostly include kinases implicated in cytosolic signaling. In contrast, extinguished kinases that result in a high mitotic index mostly include kinases implicated in cell division. By mapping hit kinases in the PhosphPOINT phosphoprotein database, we generated scale-free networks consisting of 449 and 661 protein-protein interactions for kinases from low MI and high MI groups, respectively. Further analyses of the kinase interactomes revealed specific modules such as FER- and CRKL-containing modules that connect three members of the epidermal growth factor receptor (EGFR) family, suggesting a tight control of the mitogenic EGF-dependent pathway. Based on experimental studies, we confirm the involvement of these two kinases in the regulation of tumor cell growth. Based on a combined approach of large kinome-wide siRNA screens and ontology annotations, our study identifies for the first time two kinase groups differentially implicated in the control of cell proliferation. We further demonstrate that integrative analysis of the kinase interactome provides key information which can be used to facilitate or optimize target design for new therapeutic strategies. The complete list of protein-protein interactions from the two functional kinase groups will provide a useful database for future investigations.
ISSN: 1471-2164

hal-01118475
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118475
DOI : 10.1186/1471-2164-15-1169
PUBMED : 25540073

Éditeur(s) : HAL CCSD IGI Global
Résumé : International audience
The social behavior of individuals is an important factor of the transmission and the evolution of many diseases. As such, epidemic studies have attempted to integrate social aspects in dissemination modeling. Since the pioneering works of Klovdahl on AIDS in 1985, epidemiological investigations and interventions increasingly focus on social networks. Significant factors of the transmission and outbreak of many infectious diseases are the structure and nature of human interactions. Network-based modeling approaches have found various applications in epidemiology as a simple yet efficient way to represent the complexity of human relationships implicated in dissemination processes. However, most results have been obtained by considering social networks as steady stage structures. Evolving networks have not been explored. The objective is first to give an overview of network-based modeling attempts in epidemiology to analyze and understand the dissemination processes with an emphasis on dynamic networks. The authors approach is designed to understand the impact of social links dynamics on epidemic spread. The authors present the results obtained by combining network evolution patterns (link creation and deletion) and a typical epidemic model. The speed of link dynamics and the infection time strongly influence the occurrence and value of the epidemic peak.
ISSN: 1947-8186

hal-00700105
https://hal.archives-ouvertes.fr/hal-00700105
DOI : 10.4018/jismd.2012070103

Éditeur(s) : HAL CCSD National Academy of Sciences
Résumé : International audience
All evolutionary biologists are familiar with evolutionary units that evolve by vertical descent in a tree-like fashion in single lineages. However, many other kinds of processes contribute to evolutionary diversity. In vertical descent, the genetic material of a particular evolutionary unit is propagated by replication inside its own lineage. In what we call introgressive descent, the genetic material of a particular evolutionary unit propagates into different host structures and is replicated within these host structures. Thus, introgressive descent generates a variety of evolutionary units and leaves recognizable patterns in resemblance networks. We characterize six kinds of evolutionary units, of which five involve mosaic lineages generated by introgressive descent. To facilitate detection of these units in resemblance networks, we introduce terminology based on two notions, P3s (subgraphs of three nodes: A, B, and C) and mosaic P3s, and suggest an apparatus for systematic detection of introgressive descent. Mosaic P3s correspond to a distinct type of evolutionary bond that is orthogonal to the bonds of kinship and genealogy usually examined by evolutionary biologists. We argue that recognition of these evolutionary bonds stimulates radical rethinking of key questions in evolutionary biology (e.g., the relations among evolutionary players in very early phases of evolutionary history, the origin and emergence of novelties, and the production of new lineages). This line of research will expand the study of biological complexity beyond the usual genealogical bonds, revealing additional sources of biodiversity. It provides an important step to a more realistic pluralist treatment of evolutionary complexity.
ISSN: 0027-8424

hal-01544803
https://hal.archives-ouvertes.fr/hal-01544803
DOI : 10.1073/pnas.1206541109

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
Within the framework of the international field campaign COPS (Convective and Orographically induced Precipitation Study), a large suite of state-of-the-art meteorological instrumentation was operated, partially combined for the first time. This includes networks of in situ and remote-sensing systems such as the Global Positioning System as well as a synergy of multi-wavelength passive and active remote-sensing instruments such as advanced radar and lidar systems. The COPS field phase was performed from 01 June to 31 August 2007 in a low-mountain area in southwestern Germany/eastern France covering the Vosges mountains, the Rhine valley and the Black Forest mountains. The collected dataset covers the entire evolution of convective precipitation events in complex terrain from their initiation, to their development and mature phase until their decay. Eighteen Intensive Observations Periods with 37 operation days and eight additional Special Observations Periods were performed, providing a comprehensive dataset covering different forcing conditions. In this article, an overview of the COPS scientific strategy, the field phase, and its first accomplishments is given. Highlights of the campaign are illustrated with several measurement examples. It is demonstrated that COPS research provides new insight into key processes leading to convection initiation and to the modification of precipitation by orography, in the improvement of quantitative precipitation forecasting by the assimilation of new observations, and in the performance of ensembles of convection-permitting models in complex terrain.
ISSN: 0035-9009

hal-00565513
https://hal.archives-ouvertes.fr/hal-00565513
DOI : 10.1002/qj.752

Éditeur(s) : HAL CCSD American Association of Petroleum Geologists
Résumé : In reservoir engineering, hydrodynamic properties can be estimated from downhole electrical data using heuristic models (e.g., Archie and Kozeny-Carman's equations) relating electrical conductivity to porosity and permeability. Although proven to be predictive for many sandstone reservoirs, the models mostly fail when applied to carbonate reservoirs that generally display extremely complex pore network structures. In this article, we investigate the control of the three-dimensional (3-D) geometry and morphology of the pore network on the electrical and flow properties, comparing core-scale laboratory measurements and 3-D x-ray microtomography image analysis of samples from a Miocene reefal carbonate platform located in Mallorca (Spain). The results show that micrometer- to centimeter-scale heterogeneities strongly influence the measured macroscopic physical parameters that are then used to evaluate the hydrodynamic properties of the rock, and therefore, existing models might not provide accurate descriptions because these heterogeneities occur at scales smaller than those of the integration volume of the borehole geophysical methods. However, associated with specific data processing, 3-D imagery techniques are a useful and probably unique mean to characterize the rock heterogeneity and, thus, the properties variability.
ISSN: 0149-1423

hal-00950066
https://hal.archives-ouvertes.fr/hal-00950066
DOI : 10.1306/05221312134

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A large sand injectite network is very well exposed in the area of Bevons, Southeast France. The associated sandstone turbiditic channel–fill and the host marls are the Aptian–Albian rocks of the Vocontian Basin. The sand injection network is composed of dykes, sills and sedimentary laccoliths ranging in thickness from mm to pluri–m. The dykes and sills have vertical and horizontal lengths of up to and over 100 m and 1 km, respectively. Outcrop observations show that the architecture and morphology of the sand injectites in the marls is governed by the local stress field during injection, pre–existing faults, the host–rock lithology, compaction, and distance to the potential sand source(s). The main set of dykes is oriented N50–60° perpendicular to the minimum compressive stress σ3 during sand injection. Two other sets of dykes are intruded along pre–existing syn–sedimentary faults oriented N140–150° (set 2) and N90° (set 3) during the Apto–Cenomanian interval. Sills and dykes thin laterally away from their potential sand sources and thin laterally away from them. The vertical thickness variations of the dykes and wings are more complex, as thinning away from the sand sources is often compensated by thickening toward the palaeo–surface. Based on field observations and measurements, we characterized the 3D architecture of the sand injectites and showed that the injectites probably formed due to a forceful injection from an overpressured sand body sealed by low–permeability lithologies.
ISSN: 0191-8141

hal-01243488
https://hal.archives-ouvertes.fr/hal-01243488
DOI : 10.1016/j.jsg.2015.07.001

Éditeur(s) : HAL CCSD Springer
Résumé : International audience
Traditional network generation models aim to replicate global structural properties observed on various real-world networks through synthetic link formation mechanisms such as triadic closure or preferential attachment. Nowadays, the large amount of data available allow to study more precisely the link formation processes and to compare models with real situations. In this work, we analyze the network formed by the communication activities of the users of a telephony operator for studying the link formation process. Our goal is to identify the underlying formation mechanisms and checking if they match those proposed in traditional models. Indeed, the communications emitted and received by users are strong indicators for understanding the underlying patterns of the link formation process and highlighting how some individual properties induce the formation process in such a network. In a first study conducted at a global level, we show that the traditional mechanisms commonly used in network generation models cannot reproduce alone the link formation in this network. In a second study, we adopt a new point of view and analyze locally the link formation process by searching for correlations between some user attributes and the formation of the new links. The results obtained show that a very strong percentage of new links are formed between individuals with strong similarity.
ISSN: 1869-5450

hal-01312310
https://hal.univ-antilles.fr/hal-01312310
DOI : 10.1007/s13278-015-0304-y

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: Increasingly, similarity networks are being used for evolutionary analyses of molecular datasets. These networks are very useful, in particular for the analysis of gene sharing, lateral gene transfer and for the detection of distant homologs. Currently, such analyses require some computer programming skills due to the limited availability of user-friendly freely distributed software. Consequently, although appealing, the construction and analyses of these networks remain less familiar to biologists than do phylogenetic approaches. Results: In order to ease the use of similarity networks in the community of evolutionary biologists, we introduce a software program, EGN, that runs under Linux or MacOSX. EGN automates the reconstruction of gene and genome networks from nucleic and proteic sequences. EGN also implements statistics describing genetic diversity in these samples, for various user-defined thresholds of similarities. In the interest of studying the complexity of evolutionary processes affecting microbial evolution, we applied EGN to a dataset of 571,044 proteic sequences from the three domains of life and from mobile elements. We observed that, in Borrelia, plasmids play a different role than in most other eubacteria. Rather than being genetic couriers involved in lateral gene transfer, Borrelia's plasmids and their genes act as private genetic goods, that contribute to the creation of genetic diversity within their parasitic hosts. Conclusion: EGN can be used for constructing, analyzing, and mining molecular datasets in evolutionary studies. The program can help increase our knowledge of the processes through which genes from distinct sources and/or from multiple genomes co-evolve in lineages of cellular organisms.
ISSN: 1471-2148

hal-01544799
https://hal.archives-ouvertes.fr/hal-01544799
DOI : 10.1186/1471-2148-13-146

Éditeur(s) : HAL CCSD
Résumé : International audience
In this work, we have led an analysis of the error of different global solar radiation prediction models according to the global solar radiation variability. Different predictions models where performed such as machine learning techniques (Neural Networks, Gaussian processes and support vector machines) in order to forecast the Global Horizontal solar Irradiance (GHI). We also include in this study a simple linear autoregressive (AR) model as well as two naive models based on persistence of the GHI and persistence of the clear sky index (denoted herein scaled persistence model). The models are calibrated and tested with data from three 3 French islands: Corsica (42.15°N ; 9.08°E), Guadeloupe (16.25°N ; 61.58°W) and Reunion (21.15°S ; 55.5°E). Guadeloupe and Reunion are located in a subtropical climatic zone whereas Corsica is in a tempered climatic zone. Hence the global solar radiation variation differs significantly. The output error of the different models was quantified by the nRSME. In order to quantify the influence of the global solar radiation variability on the forecasting models error we performed a classification of typical days according to different typical days. Each class of typical day is defined by a variation of global solar radiation rate. For each class and for each location, the selected forecasting models where performed and the error was quantified. With this analysis a global solar radiation forecasting models can be selected according to the location, the global solar radiation fluctuations and hence the meteorological conditions. INTRODUCTION Large and frequent variations of solar radiation can be observed in tropical climates with amplitudes reaching 800 W/m² and occurring within a short time interval, from few seconds to few minutes, according to the geographical location. Such fluctuations can be due for example to the dynamic of clouds which can be very complex and depend on cloud type, size, speed and spatial distribution and, more generally, due to some specific local meteorological conditions. Thus, the solar energy forecasting, a process used to predict the amount of solar energy available in the current and near terms, might be a difficult task. Some of the best predictors found in literature are Autoregressive and moving average (ARMA) [5,7,8], Bayesian inferences [9,10], Markov chains [11], k-Nearest-Neighbors predictors [12] or artificial intelligence techniques as the Artificial Neural Network (ANN) [9-11]. Although these methodologies are potentially good in many areas, we observed in our previous studies on global radiation prediction [9,13,14] that the simple model based on the persistence of the clear sky index gives often very good results with acceptable errors [15] for short term forecasting time horizon (<= 1 hour). The goal of this paper is to determinate the influence of solar radiation variability regarding different classes of days on the expected error provided by different forecasting methods that the modeller can possibly implement. The paper is organized as follow: Section 2 describes the data we have used. Section 3 exposes the classification methodology and the results obtained for the three studied locations. In the two following sections, the forecasting methods are exposed and then 3 the errors on the forecasting results for each location and for each class are exposed.
The Third Southern African Solar Energy Conference (SASEC2015)
Kruger National Park, South Africa

Droits : info:eu-repo/semantics/OpenAccess
hal-01099487
https://hal.archives-ouvertes.fr/hal-01099487
https://hal.archives-ouvertes.fr/hal-01099487/document
https://hal.archives-ouvertes.fr/hal-01099487/file/article%20SASEC.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
The increasing development of world trade has promoted the spread of diseases. Recent events, like the H1N1 outbreak and spread, have confirmed this tendency. Everyone could observe that this kind of infectious disease often has the ability to cross countries borders and spread rapidly. Preventing, monitoring and controlling the outbreak of these diseases have appeared to be a public health problem of primary importance for years. However, although numerous works have been conducted in order to understand and study epidemics, this subject remains a topical issue because of the complexity of the phenomena. In this paper, we present new opportunities offered by the field of social networks for understanding the spread of infectious diseases. This work focuses both on techniques already used in epidemiology, and very recent works in social network analysis that open new perspectives. We give an overview of methods currently used to model and study the spread of diseases and future directions that the social network approach allows to glimpse.
2011 Fifth International Conference on Research Challenges in Information Science (RCIS)
Gosier, Guadeloupe

hal-00624364
https://hal.archives-ouvertes.fr/hal-00624364
DOI : 10.1109/RCIS.2011.6006866

Éditeur(s) : HAL CCSD
Résumé : International audience
EmailPrintRequest PermissionsThe emergence of new communication means such as online newspapers and exchange and sharing websites allow us to go further in the understanding of diffusion phenomena. Indeed, these public discussion areas are now firmly established in our societies and are known to be strong sensors of both human behaviors and collective feelings. In this paper we focus on diffusion phenomena that occur on Twitter and we propose a set of measures that aims to characterize globally and locally the processes. Our objective is to identify what are the conditions in which a person decides to forward the information. Our measures have been used to study two events occurred in January 2015: the presentation of Microsoft HoloLens, a new augmented reality headset, and the political election in Greece. The results obtained show a strong heterogeneity in the individual behaviours involved in the diffusion process. Our approach has been implemented into a graphical tool which is able to conduct real time analysis on any kind of topics occurring on Twitter.
IEEE International Conference on Research Challenges in Information Science (RCIS)
Athens, Greece

hal-01312382
https://hal.univ-antilles.fr/hal-01312382
DOI : 10.1109/RCIS.2015.7128894