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Alain Sandoz, Léa Stiefel (2022): Trust vs. control: the dilemma between data distribution and centralization.In: Proceedings of the International Conference on Privacy-Friendly and Trustworthy Technology for Society – COST Action CA19121 - Network on Privacy-Aware Audio- and Video-Based Applications for Active and Assisted Living

Equine piroplasmosis (EP) is a tick-borne disease caused by Babesia caballi and Theileria equi that is potentially emerging in non-endemic countries. We conducted a descriptive study to investigate EP prevalence and spatial distribution in an endemic region: the Camargue and the Plain of La Crau in France. In spring 2015 and 2016, we carried out sampling at stables (total n = 46) with a history of horses presenting chronic fever or weight loss. Overall, we collected blood from 632 horses, which were also inspected for ticks; these horses had been housed in the target stables for at least 1 year. We obtained 585 ticks from these horses and described land use around the stables. Real-time PCR was employed to assess T. equi and B. caballi prevalence in the horses and in the ticks found on the horses. For the horses, T. equi and B. caballi prevalence was 68.6% and 6.3%, respectively. For the ticks found on the horses, prevalence was 28.8% for T. equi and 0.85% for B. caballi. The most common tick species were, in order of frequency, Rhipicephalus bursa, R. sanguineus sl., Hyalomma marginatum, Haemaphysalis punctata, and Dermacentor sp. Horses bearing Rhipicephalus ticks occurred in wetter zones, closer to agricultural areas, permanent crops, and ditches, as well as in drier zones, in the more northern countryside. Compared to horses bearing R. bursa, horses bearing R. sanguineus sl. more frequently occurred near the Rhone River. Prevalence of T. equi in the ticks was as follows: Hyalomma marginatum (43%), Dermacentor sp. (40%), R. bursa (33%), R. sanguineus sl. (19%), and Haemaphysalis punctata (17%). In contrast, B. caballi only occurred in Dermacentor sp. (20%) and R. bursa (1%).

Background West Nile virus (WNV) and Usutu virus (USUV), two closely related flaviviruses, mainly follow an enzootic cycle involving mosquitoes and birds, but also infect humans and other mammals. Since 2010, their epidemiological situation may have shifted from irregular epidemics to endemicity in several European regions; this requires confirmation, as it could have implications for risk assessment and surveillance strategies. Aim To explore the seroprevalence in animals and humans and potential endemicity of WNV and USUV in Southern France, given a long history of WNV outbreaks and the only severe human USUV case in France in this region. Methods We evaluated the prevalence of WNV and USUV in a repeated cross-sectional study by serological and molecular analyses of human, dog, horse, bird and mosquito samples in the Camargue area, including the city of Montpellier, between 2016 and 2020. Results We observed the active transmission of both viruses and higher USUV prevalence in humans, dogs, birds and mosquitoes, while WNV prevalence was higher in horses. In 500 human samples, 15 were positive for USUV and 6 for WNV. Genetic data showed that the same lineages, WNV lineage 1a and USUV lineage Africa 3, were found in mosquitoes in 2015, 2018 and 2020. Conclusion These findings support existing literature suggesting endemisation in the study region and contribute to a better understanding of USUV and WNV circulation in Southern France. Our study underlines the importance of a One Health approach for the surveillance of these viruses.

International audience; Integrated socio-ecological decision-making is important in improving legitimacy in management decisions through effective solutions that avert conflicts. This research examined social perceptions in landscape planning and management with regard to the Greater flamingo, a flagship species along the southern French Coast. A strategic delivery to a cross-section in a social catchment (n = 87) captured the perception and the recognition of management strategies through a survey questionnaire. Analysis was conducted through a multi-method approach, triangulating qualitative and quantitative results. Results show the importance of the attachment to flamingos in local landscapes. Knowledge on flamingo ecology was relatively high and participants perceived some of the regional management options to be unfavorable for flamingos. Participants identified threats to the species and expressed concern for the future of the flamingos, challenging the legitimacy of some landscape management decisions and planning policies. This research demonstrates the role of flagship species in stimulating reflection on landscape management, addressing both the ecological and human dimensions. Understanding social perceptions of biodiversity management objectives is fundamental for effective coastal conservation.

L’article examine le cas d’une plateforme en pair-a-pair permettant l’echange de donnees privees entre operateurs de bases de donnees. Il soutient que le cas possede sur le plan de sa conception certaines proprietes associees aux communs et demontre en particulier comment une structure de gouvernance s’inscrit dans l’architecture technique. Cette observation plaide en faveur d’une specificite des communs numeriques.

International audience; Les deltas méditerranéens sont des espaces dont les milieux dépendent des aménagements anthropiques des fleuves qui les alimentent. En tant que côtes basses à climat méditerranéen, ils sont particulièrement vulnérables aux effets probables des changements climatiques. L'étude de trois deltas (Rhône, Vardar et Gediz) montre que les pratiques de leurs habitants associent adaptation locale et prise de conscience globale, mais aucune adaptation efficace n'est possible sans gestion concertée à plusieurs échelles. Bibliographie | citer cet article Pour faire face aux risques liés aux changements climatiques, et d'une manière plus générale aux changements globaux, il est important de travailler à différentes échelles (internationale, nationale et locale) (Dewulf, Meijerink, Runhaar 2015). Des réponses adaptatives qui combineraient approche descendante et approche ascendante pourraient être développées. Cette démarche permettrait d'émettre des propositions qui prendraient mieux en compte les besoins de la population locale mais également de stimuler des changements de comportement et d'action à tous les niveaux. La prédisposition des populations à mettre en oeuvre des stratégies d'atténuation et d'adaptation, ainsi qu'à soutenir et à inciter les gouvernements à faire de même, est davantage liée aux niveaux perçus des menaces qu'aux risques réels (O'Connell-Rodwell et al., 2000). Les travaux sur la perception des risques environnementaux, et autres études, ont montré que les individus tirent des conclusions sur les phénomènes abstraits basées sur leurs expériences observées et vécues (Capstick and Pidgeon 2014). La recherche a montré que la prise de conscience du changement climatique est souvent motivée par des facteurs spécifiques au pays comme la prospérité nationale, la couverture médiatique de la question, l'action politique par les élites politiques, les sources d'information et les gouvernements. Des facteurs individuels tels que les croyances, les connaissances et points de vue culturels jouent également un rôle important (Shi, Visschers, and Siegrist, 2015). Tous ces aspects contribuent à la perception publique et personnelle du risque et peuvent accroître la volonté des populations à prendre des mesures pour réduire les risques liés au changement climatique et s'adapter aux nouvelles conditions. L'intérêt porté par la recherche et la société civile au changement climatique est allé croissant au cours de la dernière décennie avec un accord général sur le fait que l'évolution de l'agenda politique et des mesures de gestion sont nécessaires pour faire face aux changements prévus. La région méditerranéenne a été reconnue comme l'une des régions les plus touchées par le changement climatique. Elle est considérée comme un «point chaud» selon les résultats des scénarios de projection du changement climatique mondial (Adloff et al., 2015). Les températures dans le bassin méditerranéen sont maintenant environ 1,3°C supérieures à celles de 1880-1920, pour une augmentation d'environ 0,85°C à l'échelle mondiale. Ces changements requièrent des politiques d'adaptation dans la région méditerranéenne, notamment en ce qui concerne les systèmes d'utilisation des terres et la conservation de la biodiversité (Guiot and Cramer 2016). Cet essai géo-socio-climatique ne prétend pas proposer des solutions uniques pour s'adapter aux changements climatiques. Nous présentons les perceptions au changement climatique dans trois deltas méditerranéens ainsi que les actions prises en compte par la population locale face à ces risques. Cette information est impérative pour comprendre et trouver des stratégies d'atténuation et d'adaptation les plus adéquats pour l'avenir.

International audience

Participatory mapping provides a way to collate a wide range of landscape values providing a visual representation to inform conservation planning. We tested the use of an iconic species, the Greater Flamingo, as a lens for participatory mapping to render explicit the socio-cultural values attributed in a landscape. Spatial information on six landscape values in a biodiversity hotspot, the Camargue Biosphere Reserve (southern France) was collected from 113 participants through surveys, interviews and workshops. This data was geo-located through a SoftGIS methodology to map and quantify the overlap of bivariate hotspots identifying value concurrence. The most frequent values recorded through total number of polygons and surface areas were wilderness and recreation. The least frequently mapped values were economic loss and biodiversity. There was frequent concurrence between biodiversity and aesthetic values especially in wetlands (lagoons, salt flats and sea). There was also frequent concurrence between biodiversity and recreational values with more overlap in sites with easy access (along roads and public areas). Our results show that using an iconic species is an effective way to render explicit spatial variations in the values attributed to a landscape and to identify concurrence of values, thus enabling integration of multiple landscape values in conservation planning.

Chotts are salt lakes located in the arid regions of Northern Africa. These unique wetlands are recognized for their role in the migration and breeding of waterbirds and economic values generated from mineral extraction, agriculture and tourist activities. Despite their importance for flora and fauna biodiversity, they continue to face important threats due to human activities. This article consolidates a literature review of Algerian chotts from global to local importance. An in-depth view demonstrates the changes in land use of two large chotts in the southeastern region of Algeria: Chotts Merouane and Melghir. Land use images highlight a net expansion of agricultural lands, a decrease in grazing area around the lakes and a decrease of salt lake surface area. The local focus highlights the threats and changes of Algerian and Northern African chotts and proposes some perspectives for the future.

Alternative agricultural systems, such as organic farming (OF), are promising options to sustain both agriculture productivity and environmental health. However, the adoption of OF by farmers is occurring more slowly than is advocated. A key factor limiting farmers is an inability to predict socio-economic consequences of converting to OF. To overcome this, we developed a novel method of integrated assessment of agricultural systems (IAAS) and applied it to scenarios of development of OF in the Camargue region, South of France. In collaboration with the local stakeholders, we characterized the agricultural systems at different spatial scales and defined scenario related to the future of agriculture and to OF. We then used agent-based modeling with farmers and bio-economic modeling with local stakeholders for scenario assessment. We examined the effects on the development of OF systems of key factors such as the ongoing reform in the European Common Agricultural Policy and the effects of regulations for decreased use of pesticides. The policy reform implied trends towards a diversification of crops and greater possibility for conversion to OF. Development of OF at the regional level led to improved environmental performance, but caused a decrease in profitability of the rice supply chains. In light of the observed trade-off between rice production and OF development, objectives and options towards more sustainable agricultural systems were discussed with farmers and local stakeholders. Stakeholders' assessment of the framework provided insights on the positive and specific aspects of the IAAS methodology requiring improvement. The complementarities of agent-based and bio-economic modeling provide stakeholders with a better-informed assessment of diverse scenarios, for the development of more sustainable agricultural systems.

International audience; Background: Various methods are currently used for the early detection of West Nile virus (WNV) but their outputs are not quantitative and/or do not take into account all available information. Our study aimed to test a multivariate syndromic surveillance system to evaluate if the sensitivity and the specificity of detection of WNV could be improved. Methods: Weekly time series data on nervous syndromes in horses and mortality in both horses and wild birds were used. Baselines were fitted to the three time series and used to simulate 100 years of surveillance data. WNV outbreaks were simulated and inserted into the baselines based on historical data and expert opinion. Univariate and multivariate syndromic surveillance systems were tested to gauge how well they detected the outbreaks; detection was based on an empirical Bayesian approach. The systems' performances were compared using measures of sensitivity, specificity, and area under receiver operating characteristic curve (AUC). Results: When data sources were considered separately (i.e., univariate systems), the best detection performance was obtained using the data set of nervous symptoms in horses compared to those of bird and horse mortality (AUCs equal to 0.80, 0.75, and 0.50, respectively). A multivariate outbreak detection system that used nervous symptoms in horses and bird mortality generated the best performance (AUC = 0.87). Conclusions: The proposed approach is suitable for performing multivariate syndromic surveillance of WNV outbreaks. This is particularly relevant, given that a multivariate surveillance system performed better than a univariate approach. Such a surveillance system could be especially useful in serving as an alert for the possibility of human viral infections. This approach can be also used for other diseases for which multiple sources of evidence are available.

Flamingos forage in both commercial salt pans and natural marshes and lagoons along the French Mediterranean coast. In order to assess the impact of changes in management of commercial salt pans and hydrological fluctuations on this flagship species, we evaluated the foraging areas of breeding flamingos using the resightings of 283 breeding flamingos marked with dye at the colony in 1987 and 1989, two years with contrasting hydrological conditions. Teams of observers searched all suitable habitats within 80 km of the colony during the four days following marking and recorded presence of off-duty flamingos. About one-third of the birds were found within 10 km of the colony, but some were seen up to 70 km away. About 24–54% of the birds were found in permanent brackish lagoons and 18–60% in the salt pans, the two most important habitats. In 1989, a dry year with lower water levels in the natural wetlands, the proportion of breeding flamingos using salt pans was twice as high [53%, range (47–60%)] as in 1987 [26%, range (18–29%)], this habitat thus acting as a refuge. Most of the feeding areas shown to be important for flamingos breeding in the Camargue are thus susceptible to variations according to rainfall and to transformations or drying out if the salt pans are abandoned. Our results provide essential benchmarks to reconsider the conservation of this flagship species when management of commercial salt pans changes.

To assess environmental and horse-level risk factors associated with West Nile Virus (WNV) circulation in Camargue, Southern France, a serosurvey was conducted on non-vaccinated horses (n = 1159 from 134 stables) in 2007 and 2008. Fifteen Landsat images were examined to quantify areas with open water and flooded vegetation around sampled horses. Mean percentages of areas of open water and flooded vegetation, as well as variations in these percentages between 3 periods (November to February = NOT, March to July = END and August to October = EPI), were calculated for buffers of 2 km radius around the stables. Results of the final logistic regression showed that the risk of WNV seropositivity in horses decreased with their date of acquisition and age. Results also demonstrated the significant role of environmental variables. Horse serological status was associated with variations of open water areas between the NOT (November to February) and END (March to July) periods, as well as between END and EPI (August to October). WNV spillover was found more intense in areas where water level decreased strongly from winter to spring and from spring to summer.

Part III; International audience; Is the regional conversion to Organic Farming (OF) possible? What could be the consequences at different scales in terms of social and economic development as well as nature conservation? Taking the heterogeneity of farms and farming systems in the region into account, are there farmers more prone to conversion and others that face greater obstacles? The objective of this paper is to shed light on some of these question by presenting the results of a scenario assessment carried out with regard to the extension of OF in the Camargue region in southern France. The application of different modelling approaches with great potential for the multi-scale and multi-criteria evaluation of the extension of OF is presented: bio-economic models, agent-based models and land-use/cover change models. According to our results, the most probable conversion in the near future in the Camargue would take place in fields with low salt pressure that belong to livestock breeders and diversified cereal producers. However, the regional conversion to OF is plausible since the region could maintain its economic productivity while decreasing potential harmful impacts on the environment. Finally, the possible conversion trajectories suggest that certain farmers (specialised in rice production) might need greater assistance to ensure such conversion to OF since their economic performance would be hampered during that period. The application of these three approaches to explore the same scenario in one region revealed their complementarity for tackling the complex issue of regional conversion to OF from different angles.

Durieux Laurent, Sandoz Alain, Prosper-Laget Valérie. Vers une gestion intégrée des contraintes patrimoniales : exemple du flamant rose dans le système rizicole camarguais (Note). In: Méditerranée, tome 93, 4-1999. Dynamiques naturelles et gestion des espaces littoraux, sous la direction de Serge Suanez, Mireille Provansal et Carole Bruzzi. pp. 45-48.

Sandoz Alain. Méthodologie de suivi de l'occupation du sol d'un bassin de drainage à partir d'une chaîne géomatique. In: Méditerranée, tome 85, 4-1996. Jeunes chercheurs, nouvelles orientations, nouveaux outils, sous la direction de J.L Bonnefoy, R. Courtot et J. Daligaux. pp. 43-46.

This chapter describes a holistic approach for the design of e-government platforms. It defines principles for architecting a system which must sustain the entire e-government activity of a mid-level public authority (Geneva). The four principles are: Legality, Responsibility, Transparency, and Symmetry. The principles speak to policymakers and to users. They also lead to usable and coherent architectural representations at all levels of responsibility of a project, i.e. the client, the designer and the builder. The approach resulted in deploying multipartite, distributed public services, including legal delegation of roles and the outsourcing of non mandatory tasks through PPP on an e-Government platform that will support a threefold increase in services yearly until 2012. In this sense, as well as in its daily operation, the system is a success.

The 28 August 1989 wildfire caused an important acceleration of the activity of sporadic streams, first with a thick filling during 1989-1990 and then with a cutting-down during 1990-1991. Then, it was possible to think that a precocious stabilization of morphogenesis occured owing to the swift recolonization by the vegetation. However, an exceptional flood in September 1991 showed that the stabilization remains partial., L'incendie d'août 1989 a provoqué une accélération considérable de la dynamique des ruisseaux intermittents, d'abord par une forte accumulation en 1989-1990, puis par une incision en 1990-1991. Il était alors possible de perser à une stabilisation précoce de la morphogenèse grâce à la recolonisation végétale rapide. Cependant, la crue exceptionnelle de septembre 1991 montre que cette stabilisation reste imparfaite., Ballais Jean-Louis, Bosc Marie-Chritine, Sandoz Alain. La morphogenèse sur la montagne Sainte-Victoire après l'incendie : l'exemple du ruissellement (1989-1992). In: Méditerranée, tome 75, 1-2-1992. Sainte-Victoire, hommes et paysages, sous la direction de Jean-Louis Ballais, Roland Courtot et André d'Anna. pp. 43-52.

Background West Nile Virus (WNV) affects humans and horses, potentially causing severe neurological manifestations. Recent outbreaks of West Nile fever in horses were reported in Camargue (2000, 2004), Var (2003) and Pyrenees Orientales (2006). The circulation of this virus is strongly influenced by environmental conditions. This study aimed at explaining the circulation of WNV in horses by quantifying water bodies around equine stables using Landsat images.

Le tourisme rural n'est pas nouveau. L'intérêt pour les loisirs, notamment alpins, s'est développé à la révolution industrielle, accompagné du mouvement romantique qui donne un attrait au paysage rural. Les montagnes, et les Alpes en particulier, ont été très tôt des destinations touristiques privilégiées. Plus récemment, dans les années 70, 80 et 90, on assiste à une massification progressive du tourisme rural, mais aussi à sa diversification, tant dans ses pratiques que dans ses lieux. La pénétration des " visiteurs " devient plus importante et le tourisme ne se concentre plus uniquement dans les régions des grands sites, où les paysages sont spectaculaires, mais se répand sur l'ensemble des territoires. Il se libère des grandes stations touristiques pour pénétrer jusque dans les villages éloignés et interagir avec la vie locale. Cette dynamique s'inscrit de pair avec une multiplicité des formes touristiques, chacune d'entre elle génère, dans les activités traditionnelles et dans la vie locale, des interactions, vecteurs d'une nouvelle ruralité.

In 2008 the State of Geneva modified its regulation on taxation at source in order to collect electronic fiscal data from employers. Indeed the latter provide data on their employees directly to the tax administration (AFC) and furthermore pay taxes to the State on behalf of their employees. They subtract the corresponding amounts from employees' income and refund that money to the fiscal administration. The taxation at source system is applied to foreigners who work in Switzerland or who receive Swiss pensions, to people who live in Geneva but work in other Cantons, as well as to performers, artists or speakers who work occasionally in Geneva. More than 12'000 companies and 117'000 employees are concerned by the scheme, and large companies provide data on several thousand employees. In the past these files provided by employers were handled semi-automatically by the AFC (at best). The new system (called ISEL for Impôt à la Source En Ligne) offers employers two electronic channels to provide data on employees: file transfer (.XSD) and internet e-form. This case study describes the ISEL project and its context, and discusses the issues raised by the introduction of this e-taxation system. On the human side, our paper takes a qualitative approach, based on interviews of various stakeholders involved in the project. They were asked questions on ISEL's functionality, usability, performance, and so on. On the technical side, the paper presents the architecting principles of the e-government approach in Geneva (Legality, Responsibility, Transparency and Symmetry) and the workflow that was implemented on top of AFC's legacy system.

In order to understand the role of foraging habitat quality on fecundity parameters we measured habitat use, breeding parameters, and body condition of chicks in six colonies of Little Egrets in southern France. The foraging habitat available differed between colonies; it was mainly natural marshes around the Carrelet colony, agricultural lands (rice fields and dry crops) around the Agon colony, a mix of agricultural and natural lands around the Redon and Fiélouse colonies, a mix of natural and urbanised/industrial lands around the Palissade colony, and mainly cultivated and urbanised lands around the Chaumont colony. The habitat attractiveness to adult Little Egret breeding was higher for natural marshes than for other habitat types. Agricultural marshes (rice fields) came next. Other human–made habitats came last. Clutch size and body condition index of chicks did not differ between colonies. Brood size was influenced by both the association of the proportion of natural marshes in the foraging area and clutch size, and the association of clutch size and the total number of heron pairs in the colony. The effect of the proportion of natural marshes could not be distinguished from the effects of the colony size. The potential influence of other parameters not taken into account in this study is discussed., Con la finalidad de conocer el papel que ejerce la calidad del hábitat alimentario sobre los parámetros de fecundidad, se evaluaron el uso del hábitat, los parámetros reproductivos y las condiciones físicas de los polluelos de seis colonias de garceta común en el sur de Francia. El hábitat alimentario disponible variaba de unas colonias a otras, siendo principalmente marismas naturales en el entorno de la colonia de Carrelet, terrenos agrícolas (campos de arroz y cultivos de secano) alrededor de la colonia de Agon, una combinación de terrenos agrícolas y naturales alrededor de las colonias de Redon y Fiélouse, una combinación de terrenos naturales y urbanizados/industriales alrededor de la colonia de Palissade, y principalmente terrenos cultivados y urbanizados alrededor de la colonia de Chaumont. En la época de reproducción, los adultos de garceta común se sienten atraídos principalmente por las marismas naturales, en detrimento de otros tipos de hábitat. Las tierras agrícolas anegadas (campos de arroz) siguen en orden de preferencia, mientras los hábitats construidos por el hombre ocupan el último lugar. El tamaño de la puesta y el índice de estado físico de los polluelos no mostraron diferencias entre las colonias. El tamaño de la nidada estuvo influenciado tanto por la asociación de la proporción de marismas naturales en el hábitat alimentario y el tamaño de la puesta, como por la asociación del tamaño de la puesta y el número total de parejas de garzas de la colonia. El efecto de la proporción de marismas naturales no se puede diferenciar del ejercido por el tamaño de la colonia. Se discute también la influencia potencial de otros parámetros que no se han tenido en cuenta en este estudio.

National audience

National audience

A 20-year-old white man presented with a localized unilateral swelling in the popliteal fossa. Ultrasound (US) showed the presence of an accessory muscle, the tensor fasciae suralis. The muscle was located in the proximal portion of the popliteal fossa, superficial to the medial head of the gastrocnemius. Its long tendon extended inferiorly to join the Achilles tendon. Magnetic resonance images correlated well with the US findings, confirming the diagnosis. Tensor fasciae suralis muscle is a rare cause of popliteal swelling and must be differentiated from other masses. Both US and magnetic resonance imaging can diagnose it but we suggest US as the first-line technique in its evaluation.

Sandoz Alain, Chauvelon Philippe. La géomatique, comme outil de suivi et de calcul des conditions hydrologiques d'une zone humide aménagée, la Camargue. In: Méditerranée, tome 93, 4-1999. Dynamiques naturelles et gestion des espaces littoraux, sous la direction de Serge Suanez, Mireille Provansal et Carole Bruzzi. p. 73.

National audience

This paper presents a new algorithm to implement causal ordering. Causal ordering was first proposed in the ISIS system developed at Cornell University. The interest of causal ordering in a distributed system is that it is cheaper to realize than total ordering. The implementation of causal ordering proposed in this paper uses logical clocks of Mattern-Fidge (which define a partial order between events in a distributed system) and presents two advantages over the implementation in ISIS: (1) the information added to messages to ensure causal ordering is bounded by the number of sites in the system, and (2) no special protocol is needed to dispose of this added information when it has become useless. The implementation of ISIS presents however advantages in the case of site failures.

DUPLEX is a distributed collaborative editor for users connected through a large-scale environment such as the Internet. Large-scale implies heterogeneity, unpredictable communication delays and failures, and inefficient implementations of techniques traditionally used for collaborative editing in local area networks. To cope with these unfavorable conditions, DUPLEX proposes a model based on splitting the document into independent parts, maintained individually and replicated by a kernel. Users act on document parts and interact with co-authors using a local environment providing a safe store and recovery mechanisms against failures or divergence with co-authors. Communication is reduced to a minimum, allowing disconnected operation. Atomicity, concurrency, and replica control are confined to a manageable small context.

A stable property in a distributed system is a global property which once true, remains true forever. This paper refines this notion by formally introducing the concept of strong stable properties. A strong stable property has the nice property that it can be correctly evaluated on the consistent part of uncoordinated snapshots. Termination and deadlock are shown to be strong stable properties, whereas distributed garbage is not. We also show how to derive a simple generic algorithm for the detection of a strong stable property. The generic algorithm is illustrated by two examples: termination detection and deadlock detection. Incidentally the paper presents a very simple algorithm for termination detection.

Does foraging habitat quality affect reproductive performance in the Little Egret, Egretta garzetta?— In order to understand the role of foraging habitat quality on fecundity parameters we measured habitat use, breeding parameters, and body condition of chicks in six colonies of Little Egrets in southern France. The foraging habitat available differed between colonies; it was mainly natural marshes around the Carrelet colony, agricultural lands (rice fields and dry crops) around the Agon colony, a mix of agricultural and natural lands around the Redon and Fiélouse colonies, a mix of natural and urbanised/industrial lands around the Palissade colony, and mainly cultivated and urbanised lands around the Chaumont colony. The habitat attractiveness to adult Little Egret breeding was higher for natural marshes than for other habitat types. Agricultural marshes (rice fields) came next. Other human–made habitats came last. Clutch size and body condition index of chicks did not differ between colonies. Brood size was influenced by both the association of the proportion of natural marshes in the foraging area and clutch size, and the association of clutch size and the total number of heron pairs in the colony. The effect of the proportion of natural marshes could not be distinguished from the effects of the colony size. The potential influence of other parameters not taken into account in this study is discussed.

International audience

National audience

The paper considers the problem of implementing "Virtually Synchronous Communication" in the primary partition of an asynchronous system. Virtually Synchronous Communication was first introduced by the Isis system as a powerful mechanism for building fault-tolerant processes that mask failures by replication: it can be understood as a rule for ordering message deliveries (reliable multicasts) with respect to view changes, defined by a membership service. Primary partition Virtually Synchronous Communication, noted PP-VCS, is the problem of implementing Virtually Synchronous Communication in the case of totally ordered views. The paper formally defines the problem, and shows that surprisingly this problem is harder than consensus: (1) consensus is solvable whenever the PP-VCS problem is solvable, however (2) there are environments where consensus is solvable, but not PP-VCS. The paper also defines an environment is which PP-VCS can be solved. The practical consequences of the result are discussed.

International audience