Rôle de l\u27authenticité dans le cycle de vie des documents numériques

Intervention au colloque "Le numérique : impact sur le cycle de vie du document", organisé à l\u27université de Montréal par l\u27EBSI et l\u27ENSSIB du 13 au 15 octobre 2004. Le concept d\u27authenticité est au centre de la création et de la gestion des documents d\u27archives. Cet article se propose de suivre les diverses ramifications du concept d\u27authenticité tel qu\u27il peut s\u27appliquer aux documents numériques et aux documents d\u27archives diplomatiques, juridiques et informatiques. Il s\u27agit par ailleurs d\u27examiner l\u27impact de ce concept à chaque phase du modèle du cycle de vie. Des projets de recherche en cours, tel le Projet InterPARES, mettent en avant des exigences fonctionnelles touchant à la gestion et au traitement des documents numériques

Varying-coefficients for regional quantile via KNN-based LASSO with applications to health outcome study

Health outcomes, such as body mass index and cholesterol levels, are known to be dependent on age and exhibit varying effects with their associated risk factors. In this paper, we propose a novel framework for dynamic modeling of the associations between health outcomes and risk factors using varying-coefficients (VC) regional quantile regression via K-nearest neighbors (KNN) fused Lasso, which captures the time-varying effects of age. The proposed method has strong theoretical properties, including a tight estimation error bound and the ability to detect exact clustered patterns under certain regularity conditions. To efficiently solve the resulting optimization problem, we develop an alternating direction method of multipliers (ADMM) algorithm. Our empirical results demonstrate the efficacy of the proposed method in capturing the complex age-dependent associations between health outcomes and their risk factors

SafePath: Differentially-private publishing of passenger trajectories in transportation systems

© 2018 Elsevier B.V. In recent years, the collection of spatio-temporal data that captures human movements has increased tremendously due to the advancements in hardware and software systems capable of collecting person-specific data. The bulk of the data collected by these systems has numerous applications, or it can simply be used for general data analysis. Therefore, publishing such big data is greatly beneficial for data recipients. However, in its raw form, the collected data contains sensitive information pertaining to the individuals from which it was collected and must be anonymized before publication. In this paper, we study the problem of privacy-preserving passenger trajectories publishing and propose a solution under the rigorous differential privacy model. Unlike sequential data, which describes sequentiality between data items, handling spatio-temporal data is a challenging task due to the fact that introducing a temporal dimension results in extreme sparseness. Our proposed solution introduces an efficient algorithm, called SafePath, that models trajectories as a noisy prefix tree and publishes ϵ-differentially-private trajectories while minimizing the impact on data utility. Experimental evaluation on real-life transit data in Montreal suggests that SafePath significantly improves efficiency and scalability with respect to large and sparse datasets, while achieving comparable results to existing solutions in terms of the utility of the sanitized data

Plant species colonization in newly created road habitats of South Korea: insights for more effective restoration

Despite the advances in restoration methods for newly created road habitats such as roadcuts and embankments, implementation in different parts of the world is limited by high cost and lack of knowledge of naturally formed plant communities. However, a cheaper alternative is to relay in natural successional process in sites under optimal conditions. Thus, the first steps should focus on identifying plant species that colonize roadways and road habitats as well as optimal colonization sites. Our study aimed to describe species composition, exotic species presence, and diversity among four roadways (Jeongok-Youngjung, JG; Seolma-Gueup, SM; Singal, SG; and Samga-Daechon, DC) and three habitat types (embankments, plain areas, and roadcuts) in South Korean peninsula. The effect of some environmental factors on plant composition was also examined (soil type, soil slope, and surrounding landscape). Our results showed that established plant species composition was influenced by the interaction between roadways and habitats types, which was also the main interaction affecting plant richness and evenness. Surprisingly, environmental variables had no effect on plant species composition, with a residual amount of explained variation. A total of 48 plant species were described as indicator of different roadways and habitat types, and 50% of them were invasive or cultivated species. It appeared that different regional-dependent processes, such as northern vs. southern roadways, interact with local process in new-road habitats, producing complex patterns of plant species colonization and composition. Thus, ecological restoration solutions should be targeted at site-specific needs (local) while taking into consideration the differences between northern and southern roadways (regional). Here, regional-pool and local-constraints interaction controls plant composition and diversity during road construction in South Korea. Finally, new restoration actions should be based on plant species that have been established spontaneously in these degraded areas.This work was supported by a grant from the National Institute of Ecology (NIE), funded by the Ministry of Environment (MOE), Republic of Korea (NIE-C-2018-04). JGA was supported by a Ramón y Cajal fellowship of the Ministry of Economy, Industry and Competitiveness, Spain (RYC-2016-20528)

Anomalous Paramagnetic Effects in the Mixed State of LuNi2B2C

Anomalous paramagnetic effects in dc magnetization were observed in the mixed state of LuNi2B2C, unlike any reported previously. It appears as a kink-like feature for H > 30 kOe and becomes more prominent with increasing field. A specific heat jump at the corresponding temperature suggests that the anomaly is due to a true bulk transition. A magnetic flux transition from a square to an hexagonal lattice is consistent with the anomaly.Comment: 5 pages, 4 figure

Evidence for the Coexistence of Anisotropic Superconducting Gap and Nonlocal Effects in the Non-magnetic Superconductor LuNi2B2C

A study of the dependence of the heat capacity Cp(alpha) on field angle in LuNi2B2C reveals an anomalous disorder effect. For pure samples, Cp(alpha) exhibits a fourfold variation as the field H < Hc2 is rotated in the [001] plane, with minima along (alpha = 0). A slightly disordered sample, however, develops anomalous secondary minima along for H > 1 T, leading to an 8-fold pattern. The anomalous pattern is discussed in terms of coexisting superconducting gap anisotropy and non-local effects.Comment: 5 pages, 4 figure

Hypoxia-inducible factor-1 alpha regulates microglial functions affecting neuronal survival in the acute phase of ischemic stroke in mice

Cells universally adapt to ischemic conditions by turning on a transcription factor hypoxia-inducible factor (HIF), in which its role is known to differ widely across many different types of cells. Given that microglia have been reported as an essential mediator of neuroinflammation in many brain diseases, we examined the role of HIF in microglia in the progression of an acute phase of ischemic stroke by challenging our novel strains of myeloid-specific Hif-1 alpha or Hif-2 alpha knockout (KO) mice created by Cre-loxP system via middle cerebral artery occlusion (MCAO). We observed that Hif-1 alpha but not Hif-2 alpha KO mice exhibited an improved recovery compared to wild-type (WT) mice determined by behavioral tests. Immunostaining analyses revealed that there were increased numbers of both mature and immature neurons while microglia and apoptotic cells were significantly decreased in the dentate gyrus of Hif-1 alpha KO mice following MCAO. By isolating microglia with fluorescence-activated cell sorter, we found that HIF-1 alpha-deficient microglia were impaired in phagocytosis, reactive oxygen species (ROS) production, and tumor necrosis factor-alpha (TNF-alpha) secretion. We further observed a significant decrease in the expression of Cd36 and milk fat globule-epidermal growth factor 8 (Mfg-e8) genes, both of which contain hypoxia-responsive element (HRE). Knocking down either of these genes in BV2 microglial cells was sufficient to abrogate HIF-mediated increase in phagocytosis, production of intracellular ROS, or TNF-alpha secretion. Our results therefore suggest that HIF-1 alpha in microglia is a novel therapeutic target to protect neuronal survival following an acute phase of ischemic stroke.113Ysciescopu

Auxin mediates the touch-induced mechanical stimulation of adventitious root formation under windy conditions in Brachypodium distachyon

Abstract Background It is widely perceived that mechanical or thigmomorphogenic stimuli, such as rubbing and bending by passing animals, wind, raindrop, and flooding, broadly influence plant growth and developmental patterning. In particular, wind-driven mechanical stimulation is known to induce the incidence of radial expansion and shorter and stockier statue. Wind stimulation also affects the adaptive propagation of the root system in various plant species. However, it is unknown how plants sense and transmit the wind-derived mechanical signals to launch appropriate responses, leading to the wind-adaptive root growth. Results Here, we found that Brachypodium distachyon, a model grass widely used for studies on bioenergy crops and cereals, efficiently adapts to wind-mediated lodging stress by forming adventitious roots (ARs) from nonroot tissues. Experimental dissection of wind stimuli revealed that not bending of the mesocotyls but physical contact of the leaf nodes with soil particles triggers the transcriptional induction of a group of potential auxin-responsive genes encoding WUSCHEL RELATED HOMEOBOX and LATERAL ORGAN BOUNDARIES DOMAIN transcription factors, which are likely to be involved in the induction of AR formation. Conclusions Our findings would contribute to further understanding molecular mechanisms governing the initiation and development of ARs, which will be applicable to crop agriculture in extreme wind climates

A retrospective analysis of second-line chemotherapy in patients with advanced gastric cancer

<p>Abstract</p> <p>Background</p> <p>Because treatment of advanced gastric cancer (AGC) patients after failure with first-line chemotherapy remains controversial, we performed this retrospective analysis based on the data obtained from 1455 patients registered in a first-line treatment cohort with respect to receiving or not receiving subsequent chemotherapy.</p> <p>Methods</p> <p>The decision for administering second-line chemotherapy was, in most cases, at the discretion of the physician. Seven-hundred twenty-five (50%) received second-line chemotherapy after first-line failure. Univariate and multivariate analyses were performed on the recognized baseline parameters for survival.</p> <p>Results</p> <p>At the time of initiating second-line chemotherapy, the patients' median age was 56 years (range, 22 to 86) and 139 (19%) had an Eastern Cooperative Oncology Group (ECOG) performance status of 2 or more. Seven (1%) complete and 108 (15%) partial responses to second-line chemotherapy were observed for an overall response rate of 16% (95% confidence interval [CI], 13 to 19%). The median progression-free and overall survivals, calculated from the start of second-line chemotherapy, were 2.9 months (95% CI, 2.6 to 3.3) and 6.7 months (95% CI, 5.8 to 7.5), respectively. Multivariate analysis revealed that low baseline hemoglobin level (hazard ratio [HR], 0.74; 95% CI 0.61–0.90) and a poor performance status (HR, 0.66; 95% CI, 0.52–0.83) were independent negative prognostic factors for overall survival.</p> <p>Conclusion</p> <p>Performance status, along with baseline hemoglobin level, could be used to identify the subgroup of patients most likely to benefit from second-line chemotherapy for AGC.</p