Persistent random walks, variable length Markov chains and piecewise deterministic Markov processes *

International audienceA classical random walk (S t , t ∈ N) is defined by S t := t n=0 X n , where (X n) are i.i.d. When the increments (X n) n∈N are a one-order Markov chain, a short memory is introduced in the dynamics of (S t). This so-called " persistent " random walk is nolonger Markovian and, under suitable conditions, the rescaled process converges towards the integrated telegraph noise (ITN) as the timescale and space-scale parameters tend to zero (see [11, 17, 18]). The ITN process is effectively non-Markovian too. The aim is to consider persistent random walks (S t) whose increments are Markov chains with variable order which can be infinite. This variable memory is enlighted by a one-to-one correspondence between (X n) and a suitable Variable Length Markov Chain (VLMC), since for a VLMC the dependency from the past can be unbounded. The key fact is to consider the non Markovian letter process (X n) as the margin of a couple (X n , M n) n≥0 where (M n) n≥0 stands for the memory of the process (X n). We prove that, under a suitable rescaling, (S n , X n , M n) converges in distribution towards a time continuous process (S 0 (t), X(t), M (t)). The process (S 0 (t)) is a semi-Markov and Piecewise Deterministic Markov Process whose paths are piecewise linear

Nested Forms with Dynamic Suggestions for Quality RDF Authoring

International audienceKnowledge acquisition is a central issue of the Semantic Web. Knowledge cannot always be automatically extracted from existing data, thus domain experts are required to manually produce it. On the one hand, learning formal languages such as RDF represents an important obstacle to non-IT experts. On the other hand, well-known data input interfaces, such as forms, do not address well the relational nature and flexibility of RDF. Furthermore, it is difficult to maintain data quality through time, and across contributors. We propose FORMULIS, a form-based interface for guided RDF authoring. It completely hides RDF notations , addresses the relational aspects with nested forms, and guides users by computing intelligent filling suggestions. Two user experiments show that FORMULIS helps users maintain good data quality, and can be used by users without Semantic Web knowledge

Ethical aspects of registry-based research in the Nordic countries

National health care registries in the Nordic countries share many attributes, but different legal and ethical frameworks represent a challenge to promoting effective joint research. Internationally, there is a lack of knowledge about how ethical matters are considered in Nordic registry-based research, and a lack of knowledge about how Nordic ethics committees operate and what is needed to obtain an approval. In this paper, we review ethical aspects of registry-based research, the legal framework, the role of ethics review boards in the Nordic countries, and the structure of the ethics application. We discuss the role of informed consent in registry-based research and how to safeguard the integrity of study participants, including vulnerable subjects and children. Our review also provides information on the different government agencies that contribute registry-based data, and a list of the major health registries in Denmark, Finland, Iceland, Norway, and Sweden. Both ethical values and conditions for registry-based research are similar in the Nordic countries. While Denmark, Finland, Iceland, Norway, and Sweden have chosen different legal frameworks, these differences can be resolved through mutual recognition of ethical applications and by harmonizing the different systems, likely leading to increased collaboration and enlarged studies

Regulation of AMH type 2 receptor expression by Bone Morphogenetic Protein 15 in ovine granulosa cells (abstract)

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La voiture, cet incontournable objet du désir : le rapport de l'individu à la voiture : approche psychologique, approche sémiologique, approche philosophique, approche sociologique

Ce document reprend les différentes interventions qui ont eu lieu au cours de l'atelier « vivre en ville » sur le thème : « la voiture, cet incontournable objet de désir D.Les différents intervenants :-Maryse PERVANCHON, psychologue et auteur du livre « du monde social au monde de la voiture »,-Mustapha MAKHLOUFI, sémiologue au CERTU,-Pierre ANSAY, philosophe-Catherine ESPINASSE ET Peggy BUHAGIAR, psychosociologues en dépassant le débat « pour ou contre la voiture » par des approches diverses et complémentaires ont mi sen avant les dimensions paradoxales de notre rapport à « l'objet-voiture ».Ils nous ont permis de prendre conscience de l'existence de liens élémentaires conscients ou inconscients,que nous entretenons avec elle et de montrer ainsi les limites psychologiques des discours technicistes oumoralisateurs ainsi que la difficulté de mettre en oeuvre des outils qui percutent une logique autre : celle du désir de l'individu

Silver eel downstream migration in fragmented rivers: use of a Bayesian model to track movements triggering and duration

Obstacles in rivers are considered to be one of the main threats to diadromous fish. As a result of the recent collapse of the European eel, the European Commission introduced a Regulation, requiring to reduce all sources of anthropogenic mortality, including those caused by passing through hydropower turbines. Improving knowledge about migration triggers and processes is crucial to assess and mitigate the impact of obstacles. In our study, we tracked 97 tagged silver eels in a fragmented river situated in the Western France (the River Dronne). Using the movement ecology framework, and implementing a Bayesian state-space model, we confirmed the influence of river discharge on migration triggering and he distance travelled by fish. We also demonstrated that, in our studied area, there is a small window of opportunity for migration. Moreover, we found that obstacles have a significant impact on distance travelled. Combined with the small window, this suggests that assessment of obstacles impact on downstream migration should not be limited to quantifying mortality at hydroelectric facilities, but should also consider the delay induced by obstacles, and its effects on escapement. The study also suggests that temporary turbines shutdown may mitigate the impacts of hydropower facilities in rivers with migration process similar to those observed here

Livestock Policy: Progressive Globalization Currently Focused on Environmental Issue, Food Quality and Safety in the Past and New Human-Animal Relationship in the Future

Facing critics regarding the environmental impacts of livestock activities during the past decades, the MOUVE project and the LIFLOD network have developed a specific research to better understand the consequences of livestock policy at both the local and global scales. In 2006, the FAO book “Livestock Long Shadow” (Steinfeld et al., 2006) drew attention on the environmental impacts of the livestock activities. Facing the incredible awareness, the FAO team tried to mitigate the critics by highlighting the positive functions of livestock (Steinfeld et al., 2010; Gerber et al., 2010; Gerber et al., 2013). Some decades before, in the 70s and 80s, scientists have mentioned the role of livestock in the desertification (Leeuw & Reid, 1995; USGS, 1997, FAO, 1995) and deforestation in the Amazon (Wood& Porro, 2002; Veiga et al. 2004; Kaimowitz et al., 2004, Sayago et al., 2010). In the same time, policymakers of OCDE countries started to face the challenge of nitrogen pollution (Carpenter et al., 1998). Moreover, along the forty last years, the animal production sector has been involved in several public health crises and food safety scandals. So after strongly marking the history of rural societies, livestock has become a global challenge (Delgado et al., 1999; Hann et al., 2001; Gerber et al., 2010). One of our research questions is why the livestock sector, which has resisted several crises cannot overcome this current environmental crisis. What are the links between the policies, the trajectories and dynamics of livestock at the local and global scale? What are the main steps, the major ruptures, and the factors of change…

Authors' Reply to Coste et al.: "Levothyrox® New and Old Formulations: Are they Switchable for Millions of Patients?"

"Authors'Reply to Coste et al"International audienc

Comparison of SMOS and SMAP Soil Moisture Retrieval Approaches Using Tower-based Radiometer Data over a Vineyard Field

The objective of this study was to compare several approaches to soil moisture (SM) retrieval using L-band microwave radiometry. The comparison was based on a brightness temperature (TB) data set acquired since 2010 by the L-band radiometer ELBARA-II over a vineyard field at the Valencia Anchor Station (VAS) site. ELBARA-II, provided by the European Space Agency (ESA) within the scientific program of the SMOS (Soil Moisture and Ocean Salinity) mission, measures multiangular TB data at horizontal and vertical polarization for a range of incidence angles (30-60). Based on a three year data set (2010-2012), several SM retrieval approaches developed for spaceborne missions including AMSR-E (Advanced Microwave Scanning Radiometer for EOS), SMAP (Soil Moisture Active Passive) and SMOS were compared. The approaches include: the Single Channel Algorithm (SCA) for horizontal (SCA-H) and vertical (SCA-V) polarizations, the Dual Channel Algorithm (DCA), the Land Parameter Retrieval Model (LPRM) and two simplified approaches based on statistical regressions (referred to as 'Mattar' and 'Saleh'). Time series of vegetation indices required for three of the algorithms (SCA-H, SCA-V and Mattar) were obtained from MODIS observations. The SM retrievals were evaluated against reference SM values estimated from a multiangular 2-Parameter inversion approach. The results obtained with the current base line algorithms developed for SMAP (SCA-H and -V) are in very good agreement with the reference SM data set derived from the multi-angular observations (R2 around 0.90, RMSE varying between 0.035 and 0.056 m3m3 for several retrieval configurations). This result showed that, provided the relationship between vegetation optical depth and a remotely-sensed vegetation index can be calibrated, the SCA algorithms can provide results very close to those obtained from multi-angular observations in this study area. The approaches based on statistical regressions provided similar results and the best accuracy was obtained with the Saleh methods based on either bi-angular or bipolarization observations (R2 around 0.93, RMSE around 0.035 m3m3). The LPRM and DCA algorithms were found to be slightly less successful in retrieving the 'reference' SM time series (R2 around 0.75, RMSE around 0.055 m3m3). However, the two above approaches have the great advantage of not requiring any model calibrations previous to the SM retrievals

Why Were More Than 200 Subjects Required to Demonstrate the Bioequivalence of a New Formulation of Levothyroxine with an Old One?

At the request of French Regulatory Authorities, a new formulation of Levothyrox® was licensed in France in 2017, with the objective of avoiding the stability deficiencies of an existing licensed formulation. Before launching the new formulation, an average bioequivalence (ABE) trial was conducted, having enrolled 204 subjects and selected for interpretation a narrow a priori bioequivalence range of 0.90–1.11. Bioequivalence was concluded. In a previous publication, we questioned the ability of an ABE trial to guarantee the switchability within patients of the new and old levothyroxine formulations. It was suggested that the two formulations should be compared using the conceptual framework of individual bioequivalence. The present paper is a response to those claiming that, despite the fact that ABE analysis does not formally address the switchability of the two formulations, future patients will nevertheless be fully protected. The basis for this claim is that the ABE study was established in a large trial and analyzed using a stringent a priori acceptance interval of equivalence. These claims are questionable, because the use of a very large number of subjects nullifies the implicit precautionary intention of the European guideline when, for a Narrow Therapeutic Index drug, it recommends shortening the a priori acceptance interval from 0.80–1.25 to 0.90–1.11